EN-304-617_v0.0.6.md

- LOG-3: Mandatory telemetry for enterprise management

**Threats**:

- Information disclosure through logs
- Privacy violations via telemetry
- Log tampering or deletion
- Unauthorized access to diagnostic data
- Correlation attacks using telemetry data

**Risk**: MEDIUM - Diagnostic systems may leak sensitive information while being necessary for security monitoring

**Requirements**:

#### LOG-0 Requirements (No logging or local-only)

- **LOG-0-REQ-1**: Browser shall not transmit any telemetry or diagnostic data to remote servers → Assessment: LOG-REQ-21
- **LOG-0-REQ-2**: Browser shall maintain local security event logs for audit purposes → Assessment: LOG-REQ-1
- **LOG-0-REQ-3**: Local logs shall be stored with integrity protection → Assessment: LOG-REQ-11
- **LOG-0-REQ-4**: Local logs shall implement data minimization principles → Assessment: LOG-REQ-7
- **LOG-0-REQ-5**: Browser shall provide local security dashboard for log review → Assessment: LOG-REQ-13
- **LOG-0-REQ-6**: Local logs shall support forensic export for security analysis → Assessment: LOG-REQ-17
- **LOG-0-REQ-7**: Browser shall enforce strict access controls on local log files → Assessment: LOG-REQ-20
- **LOG-0-REQ-8**: All logging shall be disabled by default with opt-in for local logging → Assessment: LOG-REQ-22
- **LOG-0-REQ-9**: Users shall be able to view and delete all local logs at any time → Assessment: LOG-REQ-23

#### LOG-1 Requirements (Opt-in telemetry with anonymization)

- **LOG-1-REQ-1**: Browser shall log security events locally → Assessment: LOG-REQ-1
- **LOG-1-REQ-2**: Browser shall log certificate errors and validation failures → Assessment: LOG-REQ-2
- **LOG-1-REQ-3**: Browser shall log extension security events → Assessment: LOG-REQ-3
- **LOG-1-REQ-4**: Browser shall support CSP violation reporting → Assessment: LOG-REQ-4
- **LOG-1-REQ-5**: Browser shall support Network Error Logging (NEL) → Assessment: LOG-REQ-5
- **LOG-1-REQ-6**: Browser shall implement crash reporting with user consent → Assessment: LOG-REQ-6
- **LOG-1-REQ-7**: Browser shall minimize data collection in logs → Assessment: LOG-REQ-7
- **LOG-1-REQ-8**: Browser shall anonymize telemetry data before transmission → Assessment: LOG-REQ-8
- **LOG-1-REQ-9**: Browser shall require explicit user consent for all telemetry → Assessment: LOG-REQ-9
- **LOG-1-REQ-10**: Browser shall transmit logs over secure channels only → Assessment: LOG-REQ-10
- **LOG-1-REQ-11**: Browser shall protect log integrity with cryptographic signatures → Assessment: LOG-REQ-11
- **LOG-1-REQ-12**: Browser shall enforce log retention policies → Assessment: LOG-REQ-12
- **LOG-1-REQ-13**: Browser shall provide security dashboard for log review → Assessment: LOG-REQ-13
- **LOG-1-REQ-14**: Browser shall use privacy-preserving analytics techniques → Assessment: LOG-REQ-18
- **LOG-1-REQ-15**: Browser shall enforce access controls on diagnostic data → Assessment: LOG-REQ-20
- **LOG-1-REQ-16**: Telemetry shall be disabled by default and require explicit opt-in → Assessment: LOG-REQ-24
- **LOG-1-REQ-17**: Users shall have granular control over telemetry categories → Assessment: LOG-REQ-25
- **LOG-1-REQ-18**: Browser shall provide clear documentation of all collected data → Assessment: LOG-REQ-26

#### LOG-2 Requirements (Default telemetry with opt-out)

- **LOG-2-REQ-1**: Browser shall log security events → Assessment: LOG-REQ-1
- **LOG-2-REQ-2**: Browser shall log certificate errors → Assessment: LOG-REQ-2
- **LOG-2-REQ-3**: Browser shall log extension security events → Assessment: LOG-REQ-3
- **LOG-2-REQ-4**: Browser shall support CSP violation reporting → Assessment: LOG-REQ-4
- **LOG-2-REQ-5**: Browser shall support Network Error Logging → Assessment: LOG-REQ-5
- **LOG-2-REQ-6**: Browser shall implement crash reporting → Assessment: LOG-REQ-6
- **LOG-2-REQ-7**: Browser shall minimize logged data → Assessment: LOG-REQ-7
- **LOG-2-REQ-8**: Browser shall anonymize telemetry data → Assessment: LOG-REQ-8
- **LOG-2-REQ-9**: Browser shall provide clear opt-out mechanism during first run → Assessment: LOG-REQ-9
- **LOG-2-REQ-10**: Browser shall transmit logs securely → Assessment: LOG-REQ-10
- **LOG-2-REQ-11**: Browser shall protect log integrity → Assessment: LOG-REQ-11
- **LOG-2-REQ-12**: Browser shall enforce retention policies → Assessment: LOG-REQ-12
- **LOG-2-REQ-13**: Browser shall provide security dashboard → Assessment: LOG-REQ-13
- **LOG-2-REQ-14**: Browser shall support incident detection → Assessment: LOG-REQ-14
- **LOG-2-REQ-15**: Browser shall maintain complete audit trail → Assessment: LOG-REQ-15
- **LOG-2-REQ-16**: Browser shall use privacy-preserving analytics → Assessment: LOG-REQ-18
- **LOG-2-REQ-17**: Browser shall support compliance logging → Assessment: LOG-REQ-19
- **LOG-2-REQ-18**: Browser shall enforce log access controls → Assessment: LOG-REQ-20
- **LOG-2-REQ-19**: Users shall be able to disable telemetry at any time → Assessment: LOG-REQ-27
- **LOG-2-REQ-20**: Browser shall display telemetry status in settings UI → Assessment: LOG-REQ-28

#### LOG-3 Requirements (Mandatory telemetry for enterprise)

- **LOG-3-REQ-1**: Browser shall log all security events → Assessment: LOG-REQ-1
- **LOG-3-REQ-2**: Browser shall log certificate errors and security warnings → Assessment: LOG-REQ-2
- **LOG-3-REQ-3**: Browser shall log all extension security events → Assessment: LOG-REQ-3
- **LOG-3-REQ-4**: Browser shall support CSP violation reporting → Assessment: LOG-REQ-4
- **LOG-3-REQ-5**: Browser shall support Network Error Logging → Assessment: LOG-REQ-5
- **LOG-3-REQ-6**: Browser shall implement comprehensive crash reporting → Assessment: LOG-REQ-6
- **LOG-3-REQ-7**: Browser shall log data with minimal redaction for forensics → Assessment: LOG-REQ-7
- **LOG-3-REQ-8**: Browser shall transmit logs securely to enterprise SIEM → Assessment: LOG-REQ-10
- **LOG-3-REQ-9**: Browser shall protect log integrity with cryptographic controls → Assessment: LOG-REQ-11
- **LOG-3-REQ-10**: Browser shall enforce enterprise-defined retention policies → Assessment: LOG-REQ-12
- **LOG-3-REQ-11**: Browser shall provide comprehensive security dashboard → Assessment: LOG-REQ-13
- **LOG-3-REQ-12**: Browser shall support real-time incident detection → Assessment: LOG-REQ-14
- **LOG-3-REQ-13**: Browser shall maintain complete audit trail of all security events → Assessment: LOG-REQ-15
- **LOG-3-REQ-14**: Browser shall support real-time security alerts → Assessment: LOG-REQ-16
- **LOG-3-REQ-15**: Browser shall support forensic log export in standard formats → Assessment: LOG-REQ-17
- **LOG-3-REQ-16**: Browser shall implement compliance logging for regulatory requirements → Assessment: LOG-REQ-19
- **LOG-3-REQ-17**: Browser shall enforce role-based access controls for logs → Assessment: LOG-REQ-20
- **LOG-3-REQ-18**: Enterprise policies shall prevent users from disabling mandatory logging → Assessment: LOG-REQ-29
- **LOG-3-REQ-19**: Browser shall support integration with enterprise monitoring systems → Assessment: LOG-REQ-30
- **LOG-3-REQ-20**: Browser shall provide tamper-evident logging mechanisms → Assessment: LOG-REQ-31

### 5.5 Update Delivery Mechanisms

#### 5.5.1 Security Update Management

**[UPD]** The manufacturer shall implement secure update mechanisms that balance security needs with user autonomy.

**Capability**: Automatic security updates with user notification and control options

**Conditions**:

- UPD-0: Forced automatic updates without user control
- UPD-1: Automatic updates with postponement options
- UPD-2: Optional automatic updates (user should enable)
- UPD-3: Manual updates only

**Threats**:

- Exploitation of unpatched vulnerabilities
- Update channel compromise
- Malicious update injection
- Denial of service through forced updates
- Zero-day exploitation window

**Risk**: HIGH - Delayed or compromised updates leave browsers vulnerable to known exploits

**Requirements**:

#### UPD-0 Requirements (Forced automatic updates)

- **UPD-0-REQ-1**: Browser shall implement automatic update mechanism without user control → Assessment: UPD-REQ-1
- **UPD-0-REQ-2**: Browser shall verify digital signatures on all updates → Assessment: UPD-REQ-2
- **UPD-0-REQ-3**: Browser shall deliver updates exclusively over HTTPS → Assessment: UPD-REQ-3
- **UPD-0-REQ-4**: Browser shall validate update manifest integrity → Assessment: UPD-REQ-4
- **UPD-0-REQ-5**: Browser shall implement rollback protection to prevent downgrade attacks → Assessment: UPD-REQ-5
- **UPD-0-REQ-6**: Browser shall isolate update channels (stable, beta, dev) → Assessment: UPD-REQ-6
- **UPD-0-REQ-7**: Browser shall support component-level updates for security patches → Assessment: UPD-REQ-7
- **UPD-0-REQ-8**: Browser shall support emergency update capability for zero-day threats → Assessment: UPD-REQ-8
- **UPD-0-REQ-9**: Browser shall verify updates before installation → Assessment: UPD-REQ-9
- **UPD-0-REQ-10**: Browser shall implement failure recovery for failed updates → Assessment: UPD-REQ-10
- **UPD-0-REQ-11**: Browser shall log all updates to transparency log → Assessment: UPD-REQ-11
- **UPD-0-REQ-12**: Browser shall validate delta update security → Assessment: UPD-REQ-12
- **UPD-0-REQ-13**: Browser shall authenticate update servers with certificate pinning → Assessment: UPD-REQ-13
- **UPD-0-REQ-14**: Browser shall implement timing jitter to prevent fingerprinting → Assessment: UPD-REQ-14
- **UPD-0-REQ-15**: Browser shall enforce background update installation → Assessment: UPD-REQ-15
- **UPD-0-REQ-16**: Browser shall force critical security updates immediately → Assessment: UPD-REQ-17
- **UPD-0-REQ-17**: Browser shall verify complete update verification chain → Assessment: UPD-REQ-18
- **UPD-0-REQ-18**: Browser shall implement update source pinning → Assessment: UPD-REQ-19
- **UPD-0-REQ-19**: Browser shall verify update integrity with cryptographic hashes → Assessment: UPD-REQ-20
- **UPD-0-REQ-20**: Browser shall support staged rollout for risk mitigation → Assessment: UPD-REQ-21
- **UPD-0-REQ-21**: Browser shall validate update domain authenticity → Assessment: UPD-REQ-22
- **UPD-0-REQ-22**: Browser shall support binary reproducibility verification → Assessment: UPD-REQ-23
- **UPD-0-REQ-23**: Updates shall be applied without user intervention or postponement → Assessment: UPD-REQ-24
- **UPD-0-REQ-24**: Browser shall restart automatically after critical updates when safe → Assessment: UPD-REQ-25

#### UPD-1 Requirements (Automatic with postponement)

- **UPD-1-REQ-1**: Browser shall implement automatic update mechanism → Assessment: UPD-REQ-1
- **UPD-1-REQ-2**: Browser shall verify update signatures → Assessment: UPD-REQ-2
- **UPD-1-REQ-3**: Browser shall deliver updates over HTTPS only → Assessment: UPD-REQ-3
- **UPD-1-REQ-4**: Browser shall validate update manifest integrity → Assessment: UPD-REQ-4
- **UPD-1-REQ-5**: Browser shall implement rollback protection → Assessment: UPD-REQ-5
- **UPD-1-REQ-6**: Browser shall isolate update channels → Assessment: UPD-REQ-6
- **UPD-1-REQ-7**: Browser shall support component updates → Assessment: UPD-REQ-7
- **UPD-1-REQ-8**: Browser shall support emergency updates → Assessment: UPD-REQ-8
- **UPD-1-REQ-9**: Browser shall verify updates before installation → Assessment: UPD-REQ-9
- **UPD-1-REQ-10**: Browser shall implement update failure recovery → Assessment: UPD-REQ-10
- **UPD-1-REQ-11**: Browser shall log updates to transparency log → Assessment: UPD-REQ-11
- **UPD-1-REQ-12**: Browser shall secure delta updates → Assessment: UPD-REQ-12
- **UPD-1-REQ-13**: Browser shall authenticate update servers → Assessment: UPD-REQ-13
- **UPD-1-REQ-14**: Browser shall implement update timing jitter → Assessment: UPD-REQ-14
- **UPD-1-REQ-15**: Browser shall enforce background updates → Assessment: UPD-REQ-15
- **UPD-1-REQ-16**: Browser shall display clear update notifications → Assessment: UPD-REQ-16
- **UPD-1-REQ-17**: Browser shall force critical updates with limited postponement → Assessment: UPD-REQ-17
- **UPD-1-REQ-18**: Browser shall verify update verification chain → Assessment: UPD-REQ-18
- **UPD-1-REQ-19**: Browser shall implement update source pinning → Assessment: UPD-REQ-19
- **UPD-1-REQ-20**: Browser shall verify update integrity → Assessment: UPD-REQ-20
- **UPD-1-REQ-21**: Browser shall support staged rollouts → Assessment: UPD-REQ-21
- **UPD-1-REQ-22**: Browser shall validate update domains → Assessment: UPD-REQ-22
- **UPD-1-REQ-23**: Users shall be able to postpone non-critical updates for limited time (max 7 days) → Assessment: UPD-REQ-26
- **UPD-1-REQ-24**: Critical security updates shall not be postponable beyond 24 hours → Assessment: UPD-REQ-27
- **UPD-1-REQ-25**: Browser shall notify users of pending updates with severity indication → Assessment: UPD-REQ-28

#### UPD-2 Requirements (Optional automatic updates)

- **UPD-2-REQ-1**: Browser shall support automatic update mechanism when enabled → Assessment: UPD-REQ-1
- **UPD-2-REQ-2**: Browser shall verify update signatures → Assessment: UPD-REQ-2
- **UPD-2-REQ-3**: Browser shall deliver updates over HTTPS → Assessment: UPD-REQ-3
- **UPD-2-REQ-4**: Browser shall validate update manifest integrity → Assessment: UPD-REQ-4
- **UPD-2-REQ-5**: Browser shall implement rollback protection → Assessment: UPD-REQ-5
- **UPD-2-REQ-6**: Browser shall isolate update channels → Assessment: UPD-REQ-6
- **UPD-2-REQ-7**: Browser shall support component updates → Assessment: UPD-REQ-7
- **UPD-2-REQ-8**: Browser shall verify updates before installation → Assessment: UPD-REQ-9
- **UPD-2-REQ-9**: Browser shall implement update failure recovery → Assessment: UPD-REQ-10
- **UPD-2-REQ-10**: Browser shall authenticate update servers → Assessment: UPD-REQ-13
- **UPD-2-REQ-11**: Browser shall display update notifications → Assessment: UPD-REQ-16
- **UPD-2-REQ-12**: Browser shall verify update integrity → Assessment: UPD-REQ-20
- **UPD-2-REQ-13**: Browser shall validate update domains → Assessment: UPD-REQ-22
- **UPD-2-REQ-14**: Automatic updates shall be disabled by default → Assessment: UPD-REQ-29
- **UPD-2-REQ-15**: Browser shall prominently recommend enabling automatic updates → Assessment: UPD-REQ-30
- **UPD-2-REQ-16**: Browser shall display security warnings when updates are available → Assessment: UPD-REQ-31
- **UPD-2-REQ-17**: Browser shall provide easy mechanism to check for and install updates → Assessment: UPD-REQ-32
- **UPD-2-REQ-18**: Users shall have full control over update timing and installation → Assessment: UPD-REQ-33

#### UPD-3 Requirements (Manual updates only)

- **UPD-3-REQ-1**: Browser shall verify update signatures when manually triggered → Assessment: UPD-REQ-2
- **UPD-3-REQ-2**: Browser shall deliver updates over HTTPS → Assessment: UPD-REQ-3
- **UPD-3-REQ-3**: Browser shall validate update manifest integrity → Assessment: UPD-REQ-4
- **UPD-3-REQ-4**: Browser shall implement rollback protection → Assessment: UPD-REQ-5
- **UPD-3-REQ-5**: Browser shall verify updates before installation → Assessment: UPD-REQ-9
- **UPD-3-REQ-6**: Browser shall implement update failure recovery → Assessment: UPD-REQ-10
- **UPD-3-REQ-7**: Browser shall authenticate update servers → Assessment: UPD-REQ-13
- **UPD-3-REQ-8**: Browser shall display update availability notifications → Assessment: UPD-REQ-16
- **UPD-3-REQ-9**: Browser shall verify update integrity → Assessment: UPD-REQ-20
- **UPD-3-REQ-10**: Browser shall validate update domains → Assessment: UPD-REQ-22
- **UPD-3-REQ-11**: Browser shall provide manual update check mechanism → Assessment: UPD-REQ-34
- **UPD-3-REQ-12**: Browser shall display security warnings for outdated versions → Assessment: UPD-REQ-35
- **UPD-3-REQ-13**: Browser shall provide clear indication of available security updates → Assessment: UPD-REQ-36
- **UPD-3-REQ-14**: All updates shall require explicit user initiation → Assessment: UPD-REQ-37
- **UPD-3-REQ-15**: Browser shall display update changelog and security impact → Assessment: UPD-REQ-38

### 5.6 Protocol Handler Security

#### 5.6.1 Custom Protocol Management

**[PRO]** The manufacturer shall securely handle various communication protocols beyond standard HTTP/HTTPS.

**Capability**: Support for custom schemes, WebSocket, WebRTC, and emerging web standards

**Conditions**:

- PRO-0: HTTP/HTTPS only
- PRO-1: Standard web protocols with strict validation
- PRO-2: Custom protocols with registration system
- PRO-3: Unrestricted protocol handler registration

**Threats**:

- Protocol confusion attacks
- Scheme hijacking
- Bypass of security controls via custom protocols
- Data leakage through protocol handlers
- Local application exploitation via URL schemes

**Risk**: MEDIUM - Custom protocols can bypass standard web security controls

**Requirements**:

#### PRO-0 Requirements (HTTP/HTTPS only)

- **PRO-0-REQ-1**: Browser shall only support HTTP and HTTPS protocols → Assessment: PRO-REQ-24
- **PRO-0-REQ-2**: Browser shall reject all custom protocol handler registration attempts → Assessment: PRO-REQ-25
- **PRO-0-REQ-3**: Browser shall block access to non-standard URL schemes (file://, data://, javascript://, etc.) → Assessment: PRO-REQ-26
- **PRO-0-REQ-4**: Browser shall not provide registerProtocolHandler() API or equivalent functionality → Assessment: PRO-REQ-27
- **PRO-0-REQ-5**: Browser shall reject navigation to any non-HTTP/HTTPS protocols → Assessment: PRO-REQ-28

#### PRO-1 Requirements (Standard web protocols with strict validation)

- **PRO-1-REQ-1**: Browser shall validate all custom protocol handler registrations → Assessment: PRO-REQ-1
- **PRO-1-REQ-2**: Browser shall obtain explicit user consent before activating custom protocol handlers → Assessment: PRO-REQ-2
- **PRO-1-REQ-3**: Browser shall enforce protocol allowlists that restrict which custom schemes can be registered → Assessment: PRO-REQ-3
- **PRO-1-REQ-4**: Browser shall prevent scheme hijacking attacks → Assessment: PRO-REQ-4
- **PRO-1-REQ-5**: Browser shall sanitize protocol URL parameters before passing to handlers → Assessment: PRO-REQ-5
- **PRO-1-REQ-6**: Browser shall implement security controls for external protocol handlers → Assessment: PRO-REQ-6
- **PRO-1-REQ-7**: Browser shall provide transparent UI indicating protocol handler registration and invocation → Assessment: PRO-REQ-7
- **PRO-1-REQ-8**: Browser shall prevent protocol downgrade attacks → Assessment: PRO-REQ-8
- **PRO-1-REQ-9**: Browser shall log protocol handler registration, modification, and invocation events → Assessment: PRO-REQ-9
- **PRO-1-REQ-10**: Browser shall support web+custom scheme conventions → Assessment: PRO-REQ-10
- **PRO-1-REQ-11**: Browser shall enforce handler capability restrictions → Assessment: PRO-REQ-13
- **PRO-1-REQ-12**: Browser shall provide protocol handler revocation mechanisms → Assessment: PRO-REQ-14
- **PRO-1-REQ-13**: Browser shall enforce cross-origin protocol restrictions → Assessment: PRO-REQ-15

#### PRO-2 Requirements (Custom protocols with registration system)

- **PRO-2-REQ-1**: Browser shall implement all PRO-1 requirements
- **PRO-2-REQ-2**: Browser shall validate protocol handler persistence across sessions → Assessment: PRO-REQ-11
- **PRO-2-REQ-3**: Browser shall mitigate protocol confusion attacks → Assessment: PRO-REQ-12
- **PRO-2-REQ-4**: Browser shall validate protocol handler manifests → Assessment: PRO-REQ-16
- **PRO-2-REQ-5**: Browser shall integrate protocol handlers with Content Security Policy → Assessment: PRO-REQ-20
- **PRO-2-REQ-6**: Browser shall maintain audit trail for handler registrations → Assessment: PRO-REQ-21
- **PRO-2-REQ-7**: Browser shall enforce secure handler update mechanisms → Assessment: PRO-REQ-22
- **PRO-2-REQ-8**: Browser shall enforce handler isolation between origins → Assessment: PRO-REQ-23
- **PRO-2-REQ-9**: Browser shall support Intent URL security on Android platforms → Assessment: PRO-REQ-17
- **PRO-2-REQ-10**: Browser shall support Universal Links security on iOS platforms → Assessment: PRO-REQ-18
- **PRO-2-REQ-11**: Browser shall validate mobile deep linking security → Assessment: PRO-REQ-19
- **PRO-2-REQ-12**: Enterprise administrators shall be able to configure protocol handler allowlists and blocklists → Assessment: PRO-REQ-29

#### PRO-3 Requirements (Unrestricted protocol registration)

- **PRO-3-REQ-1**: Browser shall implement baseline protocol handler validation → Assessment: PRO-REQ-1
- **PRO-3-REQ-2**: Browser shall obtain user consent for protocol handler activation → Assessment: PRO-REQ-2
- **PRO-3-REQ-3**: Browser shall sanitize protocol parameters → Assessment: PRO-REQ-5
- **PRO-3-REQ-4**: Browser shall implement external handler security controls → Assessment: PRO-REQ-6
- **PRO-3-REQ-5**: Browser shall provide handler management UI → Assessment: PRO-REQ-7
- **PRO-3-REQ-6**: Browser shall log protocol handler security events → Assessment: PRO-REQ-9
- **PRO-3-REQ-7**: Browser shall allow registration of custom schemes without web+ prefix → Assessment: PRO-REQ-30
- **PRO-3-REQ-8**: Browser shall display security warnings for non-standard protocol handlers → Assessment: PRO-REQ-31
- **PRO-3-REQ-9**: Browser shall provide user-accessible handler revocation controls → Assessment: PRO-REQ-14
- **PRO-3-REQ-10**: Users shall be able to review all registered protocol handlers in browser settings → Assessment: PRO-REQ-32
- **PRO-3-REQ-11**: Browser shall scan custom handlers for known security vulnerabilities → Assessment: PRO-REQ-33
- **PRO-3-REQ-12**: All protocol handler security exceptions shall be logged and auditable → Assessment: PRO-REQ-34

### 5.7 Core Component Security

#### 5.7.1 System Resource Access

**[SYS]** The manufacturer shall implement secure boundaries between web content and system resources through Hardware Abstraction Layers and API mediation.

**Capability**: HAL implementation, PWA support, accessibility features, and local storage mechanisms

**Conditions**:

- SYS-0: Fully sandboxed with no system access
- SYS-1: Limited system access with strict permissions
- SYS-2: Extended system access for PWAs
- SYS-3: Native-equivalent system access

**Threats**:

- Sandbox escape attacks
- Unauthorized file system access
- Hardware fingerprinting
- Resource exhaustion attacks
- Accessibility feature abuse for screen reading

**Risk**: CRITICAL - System access breaches can compromise the entire host environment

**Requirements**:

#### SYS-0 Requirements (Fully sandboxed, no system access)

- **SYS-0-REQ-1**: Browser shall enforce process-level sandboxing for all web content → Assessment: SYS-REQ-1
- **SYS-0-REQ-2**: Browser shall isolate renderer processes from each other and browser core → Assessment: SYS-REQ-2
- **SYS-0-REQ-3**: Browser shall isolate GPU rendering in separate sandboxed process → Assessment: SYS-REQ-3
- **SYS-0-REQ-4**: Browser shall isolate network operations in separate process or service → Assessment: SYS-REQ-4
- **SYS-0-REQ-5**: Browser shall block all filesystem access from web content → Assessment: SYS-REQ-5
- **SYS-0-REQ-6**: Browser shall block all device API access (no camera, microphone, location, etc.) → Assessment: SYS-REQ-33
- **SYS-0-REQ-7**: Browser shall enforce strict hardware resource limits → Assessment: SYS-REQ-20
- **SYS-0-REQ-8**: Browser shall enforce memory isolation between processes → Assessment: SYS-REQ-21
- **SYS-0-REQ-9**: Browser shall implement sandbox escape prevention mechanisms → Assessment: SYS-REQ-26
- **SYS-0-REQ-10**: Browser shall implement Spectre/Meltdown mitigations → Assessment: SYS-REQ-27
- **SYS-0-REQ-11**: Browser shall implement side-channel attack mitigations → Assessment: SYS-REQ-28
- **SYS-0-REQ-12**: Browser shall not expose any native messaging interfaces → Assessment: SYS-REQ-34
- **SYS-0-REQ-13**: Browser shall block all host OS integration features → Assessment: SYS-REQ-35

#### SYS-1 Requirements (Limited system access with strict permissions)

- **SYS-1-REQ-1**: Browser shall enforce process-level sandboxing → Assessment: SYS-REQ-1
- **SYS-1-REQ-2**: Browser shall isolate renderer processes → Assessment: SYS-REQ-2
- **SYS-1-REQ-3**: Browser shall isolate GPU process → Assessment: SYS-REQ-3
- **SYS-1-REQ-4**: Browser shall isolate network service → Assessment: SYS-REQ-4
- **SYS-1-REQ-5**: Browser shall enforce strict filesystem access controls → Assessment: SYS-REQ-5
- **SYS-1-REQ-6**: Browser shall implement permission controls for device hardware APIs → Assessment: SYS-REQ-6
- **SYS-1-REQ-7**: Browser shall enforce geolocation permission requirements → Assessment: SYS-REQ-8
- **SYS-1-REQ-8**: Browser shall enforce camera/microphone access controls with visible indicators → Assessment: SYS-REQ-9
- **SYS-1-REQ-9**: Browser shall restrict clipboard access to require user interaction → Assessment: SYS-REQ-10
- **SYS-1-REQ-10**: Browser shall enforce notification permission management → Assessment: SYS-REQ-11
- **SYS-1-REQ-11**: Browser shall restrict Sensor API access with permissions → Assessment: SYS-REQ-18
- **SYS-1-REQ-12**: Browser shall restrict Battery Status API to prevent fingerprinting → Assessment: SYS-REQ-19
- **SYS-1-REQ-13**: Browser shall enforce hardware resource limits → Assessment: SYS-REQ-20
- **SYS-1-REQ-14**: Browser shall enforce memory isolation → Assessment: SYS-REQ-21
- **SYS-1-REQ-15**: Browser shall implement CPU resource quotas → Assessment: SYS-REQ-22
- **SYS-1-REQ-16**: Browser shall enforce network bandwidth limits → Assessment: SYS-REQ-23
- **SYS-1-REQ-17**: Browser shall enforce storage quota limits → Assessment: SYS-REQ-24
- **SYS-1-REQ-18**: Browser shall implement process priority management → Assessment: SYS-REQ-25
- **SYS-1-REQ-19**: Browser shall prevent sandbox escapes → Assessment: SYS-REQ-26
- **SYS-1-REQ-20**: Browser shall implement speculative execution mitigations → Assessment: SYS-REQ-27
- **SYS-1-REQ-21**: Browser shall implement side-channel mitigations → Assessment: SYS-REQ-28
- **SYS-1-REQ-22**: Browser shall implement accessibility API security controls → Assessment: SYS-REQ-30

#### SYS-2 Requirements (Extended system access for PWAs)

- **SYS-2-REQ-1**: Browser shall implement all SYS-1 requirements
- **SYS-2-REQ-2**: Browser shall enforce equivalent permission controls for PWAs → Assessment: SYS-REQ-7
- **SYS-2-REQ-3**: Browser shall implement USB device access security → Assessment: SYS-REQ-12
- **SYS-2-REQ-4**: Browser shall enforce Bluetooth permission controls → Assessment: SYS-REQ-13
- **SYS-2-REQ-5**: Browser shall implement File System Access API security → Assessment: SYS-REQ-14
- **SYS-2-REQ-6**: Browser shall enforce WebUSB security controls → Assessment: SYS-REQ-15
- **SYS-2-REQ-7**: Browser shall enforce WebBluetooth security → Assessment: SYS-REQ-16
- **SYS-2-REQ-8**: Browser shall implement WebNFC permission management → Assessment: SYS-REQ-17
- **SYS-2-REQ-9**: Browser shall implement hardware token security → Assessment: SYS-REQ-29
- **SYS-2-REQ-10**: Browser shall enforce restricted native messaging with security controls → Assessment: SYS-REQ-31
- **SYS-2-REQ-11**: PWA permissions shall not exceed web context permissions → Assessment: SYS-REQ-36
- **SYS-2-REQ-12**: PWA installation shall not auto-grant extended permissions → Assessment: SYS-REQ-37
- **SYS-2-REQ-13**: PWA uninstallation shall revoke all granted permissions → Assessment: SYS-REQ-38
- **SYS-2-REQ-14**: Browser shall maintain audit log of all PWA permission grants and revocations → Assessment: SYS-REQ-39
- **SYS-2-REQ-15**: Enterprise administrators shall be able to configure PWA permission policies → Assessment: SYS-REQ-40

#### SYS-3 Requirements (Native-equivalent system access)

- **SYS-3-REQ-1**: Browser shall implement baseline sandboxing for renderer processes → Assessment: SYS-REQ-1
- **SYS-3-REQ-2**: Browser shall enforce process isolation → Assessment: SYS-REQ-2
- **SYS-3-REQ-3**: Browser shall implement baseline permission controls for device APIs → Assessment: SYS-REQ-6
- **SYS-3-REQ-4**: Browser shall enforce filesystem access controls → Assessment: SYS-REQ-5
- **SYS-3-REQ-5**: Browser shall implement resource limits to prevent exhaustion → Assessment: SYS-REQ-20
- **SYS-3-REQ-6**: Browser shall implement memory isolation → Assessment: SYS-REQ-21
- **SYS-3-REQ-7**: Browser shall implement CPU quotas → Assessment: SYS-REQ-22
- **SYS-3-REQ-8**: Browser shall enforce storage quotas → Assessment: SYS-REQ-24
- **SYS-3-REQ-9**: Browser shall implement speculative execution mitigations → Assessment: SYS-REQ-27
- **SYS-3-REQ-10**: Browser shall implement side-channel mitigations → Assessment: SYS-REQ-28
- **SYS-3-REQ-11**: Browser shall enforce host OS integration security → Assessment: SYS-REQ-32
- **SYS-3-REQ-12**: Browser shall allow native-equivalent API access with user consent → Assessment: SYS-REQ-41
- **SYS-3-REQ-13**: Browser shall provide transparent UI for all native integration features → Assessment: SYS-REQ-42
- **SYS-3-REQ-14**: Browser shall display security warnings for privileged API access → Assessment: SYS-REQ-43
- **SYS-3-REQ-15**: Browser shall log all extended system access for security auditing → Assessment: SYS-REQ-44
- **SYS-3-REQ-16**: Users shall be able to review and revoke all system permissions → Assessment: SYS-REQ-45
- **SYS-3-REQ-17**: Enterprise administrators shall be able to restrict native-equivalent features → Assessment: SYS-REQ-46
- **SYS-3-REQ-18**: All native integration exceptions shall be documented and auditable → Assessment: SYS-REQ-47

## 5.8 Embedded Browser Security

### 5.8.1 Overview

Embedded browsers (WebView components, browser engines integrated into native applications) present unique security challenges distinct from standalone browsers. While standalone browsers operate as independent applications with their own security boundaries, embedded browsers exist within a host application context where they navigate the security boundary between web content and the host application.

**Key Security Challenges**:

1. **Host-Code Injection**: Malicious web content may attempt to inject code into or manipulate the host application through JavaScript bridge interfaces, custom URL scheme handlers, or exploitation of WebView API vulnerabilities.

2. **User Data Exfiltration**: Web content loaded in an embedded browser may access sensitive data from the host application through insecure bridge configurations, shared storage, or insufficient isolation between web and native contexts.

3. **Insufficient Isolation**: Unlike standalone browsers where all web content is untrusted, embedded browsers often  establish trust relationships with certain content sources while maintaining security boundaries, creating complex policy enforcement challenges.

**Risk Classification**: CRITICAL - Vulnerabilities in embedded browser security can lead to complete compromise of the host application and exfiltration of all user data accessible to the host.

**Applicable Use Cases**: UC-B08 (Embedded Browser Component), UC-B09 (WebView Component in Native Applications), and aspects of UC-B10 (Adapted Browser with Modified Features) when the adaptation includes native component integration.

**References**:

- OWASP Mobile Security Testing Guide - WebViews: https://mas.owasp.org/MASTG/tests/android/MASVS-PLATFORM/MASTG-TEST-0028/
- Android WebView Security Best Practices: https://developer.android.com/develop/ui/views/layout/webapps/webview
- iOS WKWebView Security: https://developer.apple.com/documentation/webkit/wkwebview
- Chromium Embedded Framework Security: https://bitbucket.org/chromiumembedded/cef/wiki/GeneralUsage#markdown-header-security
- Electron Security Best Practices: https://www.electronjs.org/docs/latest/tutorial/security

### 5.8.2 Host Application Boundary Security

**[EMB]** The manufacturer shall implement secure isolation boundaries between embedded browser content and host application code, data, and resources.

**Capability**: JavaScript bridge security, native API exposure control, host data protection, and context isolation

**Conditions**:

- **EMB-0**: No JavaScript bridge or native API exposure (isolated WebView)
- **EMB-1**: Limited JavaScript bridge with explicit allowlist of safe APIs
- **EMB-2**: Extended JavaScript bridge with bidirectional communication
- **EMB-3**: Full integration with access to native capabilities and host data

**Threats**:

- JavaScript injection into host application context
- Unauthorized access to native APIs through bridge exploitation
- Code execution in host process via WebView vulnerabilities
- Cross-context data leakage between web and native layers
- Exploitation of insecure JavaScript bridge configurations
- Bypass of content security policies via native bridges
- Host application credential theft via bridge access
- Native code injection via crafted web content

**Risk**: CRITICAL - Compromise of the host-browser boundary can lead to complete application takeover and data exfiltration

**Requirements**:

#### EMB-0 Requirements (No JavaScript bridge or native API exposure)

- **EMB-0-REQ-1**: Embedded browser shall implement complete context isolation → Assessment: EMB-REQ-4
- **EMB-0-REQ-2**: Embedded browser shall isolate all storage from host application → Assessment: EMB-REQ-12
- **EMB-0-REQ-3**: Embedded browser shall enforce CSP for all web content → Assessment: EMB-REQ-13
- **EMB-0-REQ-4**: Embedded browser shall prevent all web content access to host application objects → Assessment: EMB-REQ-33
- **EMB-0-REQ-5**: No JavaScript bridge or native API exposure mechanism shall exist → Assessment: EMB-REQ-34
- **EMB-0-REQ-6**: Embedded browser shall treat all loaded content as completely untrusted → Assessment: EMB-REQ-35
- **EMB-0-REQ-7**: Host application credentials shall be completely isolated from web context → Assessment: EMB-REQ-8

#### EMB-1 Requirements (Limited JavaScript bridge with explicit allowlist)

- **EMB-1-REQ-1**: JavaScript bridge shall implement explicit API allowlists with per-API access controls → Assessment: EMB-REQ-1
- **EMB-1-REQ-2**: All bridge data shall be validated, sanitized, and type-checked on native side → Assessment: EMB-REQ-2
- **EMB-1-REQ-3**: JavaScript bridge communications shall be logged → Assessment: EMB-REQ-3
- **EMB-1-REQ-4**: Embedded browser shall implement context isolation → Assessment: EMB-REQ-4
- **EMB-1-REQ-5**: Sensitive native APIs shall require explicit user consent → Assessment: EMB-REQ-5
- **EMB-1-REQ-6**: System-level APIs shall not be exposed without additional security controls → Assessment: EMB-REQ-6
- **EMB-1-REQ-7**: JavaScript bridge configuration shall be immutable after initialization → Assessment: EMB-REQ-7
- **EMB-1-REQ-8**: Web content shall not access host credentials, tokens, or keys → Assessment: EMB-REQ-8
- **EMB-1-REQ-9**: Bridge implementations shall be reviewed for injection vulnerabilities → Assessment: EMB-REQ-9
- **EMB-1-REQ-10**: Host shall implement rate limiting on bridge API calls → Assessment: EMB-REQ-10
- **EMB-1-REQ-11**: Bridge shall support granular capability-based permissions → Assessment: EMB-REQ-11
- **EMB-1-REQ-12**: Embedded browser shall isolate storage from host → Assessment: EMB-REQ-12
- **EMB-1-REQ-13**: Host shall enforce CSP for all embedded content → Assessment: EMB-REQ-13
- **EMB-1-REQ-14**: Web content shall not trigger misleading native UI → Assessment: EMB-REQ-15
- **EMB-1-REQ-15**: Host shall implement allowlists rather than denylists for bridge APIs → Assessment: EMB-REQ-16
- **EMB-1-REQ-16**: Only explicitly allowlisted APIs shall be accessible from web content → Assessment: EMB-REQ-36
- **EMB-1-REQ-17**: Bridge API allowlist shall be minimal and documented → Assessment: EMB-REQ-37

#### EMB-2 Requirements (Extended JavaScript bridge with bidirectional communication)

- **EMB-2-REQ-1**: All EMB-1 requirements shall be implemented
- **EMB-2-REQ-2**: Bridge communications crossing process boundaries shall be encrypted → Assessment: EMB-REQ-14
- **EMB-2-REQ-3**: Bridge shall implement granular permissions → Assessment: EMB-REQ-11
- **EMB-2-REQ-4**: Host shall implement comprehensive rate limiting → Assessment: EMB-REQ-10
- **EMB-2-REQ-5**: All bridge communications shall be logged with full audit trails → Assessment: EMB-REQ-3
- **EMB-2-REQ-6**: Bidirectional bridge calls shall maintain same security controls in both directions → Assessment: EMB-REQ-38
- **EMB-2-REQ-7**: Web content callback handlers shall be validated before invocation → Assessment: EMB-REQ-39
- **EMB-2-REQ-8**: Bridge shall implement message queuing with integrity protection → Assessment: EMB-REQ-40
- **EMB-2-REQ-9**: Host shall monitor bridge traffic for anomalies → Assessment: EMB-REQ-41
- **EMB-2-REQ-10**: Enterprise administrators shall be able to configure bridge API policies → Assessment: EMB-REQ-42

#### EMB-3 Requirements (Full integration with native capabilities)

- **EMB-3-REQ-1**: Baseline EMB-1 security controls shall be maintained
- **EMB-3-REQ-2**: Bridge shall implement comprehensive input validation → Assessment: EMB-REQ-2
- **EMB-3-REQ-3**: Bridge shall log all operations with security context → Assessment: EMB-REQ-3
- **EMB-3-REQ-4**: Sensitive native operations shall require user consent → Assessment: EMB-REQ-5
- **EMB-3-REQ-5**: System-level APIs shall have strict additional controls → Assessment: EMB-REQ-6
- **EMB-3-REQ-6**: Bridge implementations shall undergo security review → Assessment: EMB-REQ-9
- **EMB-3-REQ-7**: Rate limiting shall prevent bridge API abuse → Assessment: EMB-REQ-10
- **EMB-3-REQ-8**: Full integration shall not bypass core security boundaries → Assessment: EMB-REQ-43
- **EMB-3-REQ-9**: User shall be informed of all native capabilities granted to web content → Assessment: EMB-REQ-44
- **EMB-3-REQ-10**: User shall be able to review and revoke native API access → Assessment: EMB-REQ-45
- **EMB-3-REQ-11**: All native integrations shall be documented and auditable → Assessment: EMB-REQ-46
- **EMB-3-REQ-12**: Enterprise policies shall be able to restrict native integration scope → Assessment: EMB-REQ-47

### 5.8.3 Content Source Trust Management

**[EMB]** The manufacturer shall implement mechanisms to establish and enforce trust relationships between embedded browser content sources and the host application.

**Capability**: Content source validation, certificate pinning for embedded content, subresource integrity, and trust boundary enforcement

**Conditions**:

- **EMB-0**: All content treated as untrusted (public internet)
- **EMB-1**: Trusted domains with certificate validation
- **EMB-2**: Certificate pinning for specific trusted origins
- **EMB-3**: Local/bundled content with cryptographic verification

**Threats**:

- Man-in-the-middle attacks against trusted content sources
- Loading of malicious content from compromised trusted domains
- Bypass of trust boundaries through redirect chains
- Subresource substitution attacks
- DNS hijacking of embedded content sources
- Certificate authority compromise affecting trusted origins
- Mixed content attacks (trusted page loading untrusted resources)
- Cache poisoning affecting embedded content

**Risk**: CRITICAL - Compromise of trusted content sources can lead to injection of malicious code with elevated privileges

**Requirements**:

#### EMB-0 Requirements (All content treated as untrusted - public internet)

- **EMB-0-REQ-1**: All content shall be treated as completely untrusted → Assessment: EMB-REQ-35
- **EMB-0-REQ-2**: Embedded browser shall validate SSL/TLS certificates for all remote content → Assessment: EMB-REQ-17
- **EMB-0-REQ-3**: Embedded browser shall prevent all mixed content → Assessment: EMB-REQ-21
- **EMB-0-REQ-4**: Certificate validation failures shall block content loading → Assessment: EMB-REQ-26
- **EMB-0-REQ-5**: Network security configuration shall prevent cleartext traffic → Assessment: EMB-REQ-27
- **EMB-0-REQ-6**: Trust boundary violations shall trigger security events → Assessment: EMB-REQ-32
- **EMB-0-REQ-7**: No content origin shall have privileged access → Assessment: EMB-REQ-48
- **EMB-0-REQ-8**: All CSP policies shall be strictly enforced without exceptions → Assessment: EMB-REQ-49

#### EMB-1 Requirements (Trusted domains with certificate validation)

- **EMB-1-REQ-1**: Embedded browser shall validate SSL/TLS certificates for all remote content → Assessment: EMB-REQ-17
- **EMB-1-REQ-2**: Host shall implement allowlist of trusted content origins → Assessment: EMB-REQ-18
- **EMB-1-REQ-3**: Embedded browser shall prevent mixed content → Assessment: EMB-REQ-21
- **EMB-1-REQ-4**: Trust decisions shall be logged with full context → Assessment: EMB-REQ-22
- **EMB-1-REQ-5**: Host shall implement redirect chain validation → Assessment: EMB-REQ-24
- **EMB-1-REQ-6**: Embedded browser shall enforce HSTS for trusted origins → Assessment: EMB-REQ-25
- **EMB-1-REQ-7**: Certificate failures shall trigger immediate notification and blocking → Assessment: EMB-REQ-26
- **EMB-1-REQ-8**: Network security config shall prevent cleartext to trusted domains → Assessment: EMB-REQ-27
- **EMB-1-REQ-9**: Trusted content shall not load untrusted third-party content without CSP → Assessment: EMB-REQ-28
- **EMB-1-REQ-10**: Trust boundary violations shall trigger security events → Assessment: EMB-REQ-32
- **EMB-1-REQ-11**: Only explicitly allowlisted origins shall be considered trusted → Assessment: EMB-REQ-18
- **EMB-1-REQ-12**: Trust allowlist shall be immutable by web content → Assessment: EMB-REQ-50

#### EMB-2 Requirements (Certificate pinning for specific trusted origins)

- **EMB-2-REQ-1**: All EMB-1 requirements shall be implemented → Assessment: EMB-REQ-51
- **EMB-2-REQ-2**: Embedded browser shall implement certificate pinning for critical origins → Assessment: EMB-REQ-20
- **EMB-2-REQ-3**: Embedded browser shall enforce SRI for external scripts from trusted content → Assessment: EMB-REQ-19
- **EMB-2-REQ-4**: Certificate pinning shall include backup pins and rotation mechanisms → Assessment: EMB-REQ-20
- **EMB-2-REQ-5**: Trust policies shall be configurable per browser instance → Assessment: EMB-REQ-29
- **EMB-2-REQ-6**: Embedded browser shall implement certificate transparency verification → Assessment: EMB-REQ-30
- **EMB-2-REQ-7**: Host shall detect and prevent DNS rebinding attacks → Assessment: EMB-REQ-31
- **EMB-2-REQ-8**: Pin configuration shall be immutable after initialization → Assessment: EMB-REQ-52
- **EMB-2-REQ-9**: Pinning violations shall immediately block content loading → Assessment: EMB-REQ-53
- **EMB-2-REQ-10**: Pin rotation procedures shall be documented and tested → Assessment: EMB-REQ-54

#### EMB-3 Requirements (Local/bundled content with cryptographic verification)

- **EMB-3-REQ-1**: Baseline EMB-1 certificate validation shall apply to all remote content → Assessment: EMB-REQ-55
- **EMB-3-REQ-2**: Embedded browser shall verify cryptographic signatures for local/bundled content → Assessment: EMB-REQ-23
- **EMB-3-REQ-3**: Embedded browser shall enforce SRI for all external scripts → Assessment: EMB-REQ-19
- **EMB-3-REQ-4**: Certificate pinning shall be enforced for remote trusted origins → Assessment: EMB-REQ-17, EMB-REQ-20
- **EMB-3-REQ-5**: Trust decisions shall be logged comprehensively → Assessment: EMB-REQ-22
- **EMB-3-REQ-6**: Trust policies shall be configurable per instance → Assessment: EMB-REQ-29
- **EMB-3-REQ-7**: DNS rebinding prevention shall be enforced → Assessment: EMB-REQ-31
- **EMB-3-REQ-8**: Trust boundary violations shall trigger detailed security events → Assessment: EMB-REQ-32
- **EMB-3-REQ-9**: Local content signature verification shall use secure algorithms (RSA-2048+, ECDSA P-256+) → Assessment: EMB-REQ-56
- **EMB-3-REQ-10**: Modified local content shall fail signature verification and be rejected → Assessment: EMB-REQ-57
- **EMB-3-REQ-11**: Signing keys for local content shall be protected from extraction → Assessment: EMB-REQ-58
- **EMB-3-REQ-12**: Hybrid deployments (local + remote) shall maintain strictest security controls for each content type → Assessment: EMB-REQ-59

**References**:

- OWASP Mobile Top 10 - M1: Improper Platform Usage: https://owasp.org/www-project-mobile-top-10/
- CWE-749: Exposed Dangerous Method or Function: https://cwe.mitre.org/data/definitions/749.html
- CWE-940: Improper Verification of Source of a Communication Channel: https://cwe.mitre.org/data/definitions/940.html
- Android Network Security Configuration: https://developer.android.com/training/articles/security-config
- iOS App Transport Security: https://developer.apple.com/documentation/security/preventing_insecure_network_connections
- Certificate Pinning Best Practices: https://owasp.org/www-community/controls/Certificate_and_Public_Key_Pinning
- Electron Context Isolation: https://www.electronjs.org/docs/latest/tutorial/context-isolation


## 5.9 Remote Data Processing Systems

**[RDPS]** The manufacturer shall implement secure remote data processing systems that protect data confidentiality, integrity, and availability while maintaining product functionality.

**Overview**:

A remote data processing solution (RDPS) is a component of a product that has an essential role in one or more of a product's functions and performs that role remotely from the local components of the product. While many product update methods may fit into the definition of an RDPS, product update requirements are considered separately in Section 5.5 Update Delivery Mechanisms of this document.

All remote data processing solutions are components of the product, but their use is independent of the product's deployment environment. While a product's employment of an RDPS may create additional security requirements related to its remote nature and affect the tools available to an assessor, use of an RDPS does not significantly change the security requirements associated with the product's use or functions.

A remote data processing solution is a component of the product when it has been designed by or for the manufacturer or is in the manufacturer's control, and it is necessary for the product to perform its intended functions. Remote data processing solutions can perform any function of the product and are not limited to a product's core functions. Common uses of RDPS include remote storage of profile or configuration data, often to enable similar devices to use or access the data from a web interface. The system can also be a log storage or metrics collection endpoint, which is part of the product design, but those have dedicated sections in the present document with detailed requirements.

**CRA Applicability**: The CRA has a subtle difference in how the application is designed. A website that is accessed with a browser is not in scope, but an online service which is used from an installed application is in scope. The CRA Article 3(2) defines that an RDPS is under the responsibility of the manufacturer. Therefore, if the product default configuration is overwritten with local amendments by the user of the product, it is important that similar protection can be achieved as described in this section.

**Capability**: Secure remote data processing with encryption, authentication, availability controls, and data protection

**Conditions**:

- **RDPS-0**: No remote data processing (fully local operation)
- **RDPS-1**: Limited remote processing for non-sensitive data (configuration, preferences)
- **RDPS-2**: Extended remote processing including sensitive data with strong security controls
- **RDPS-3**: Full remote processing with critical data requiring maximum security

**Threats**:

- Eavesdropping and man-in-the-middle attacks during data transmission
- Unauthorized access to remote systems and data
- Data integrity compromise and unauthorized modification
- Denial of service attacks affecting service availability
- Multitenant data leakage in shared infrastructure
- Insider abuse and unauthorized access by service operators
- Data residency and sovereignty violations
- Insufficient data protection at rest
- Inadequate backup and recovery capabilities
- Vendor lock-in preventing data portability
- Service discontinuation without migration path
- Configuration tampering when user-defined RDPS endpoints allowed

**Risk**: HIGH - Compromised RDPS can lead to data theft, service disruption, privacy violations, and complete product functionality loss

**Requirements**:

#### RDPS-0 Requirements (No remote data processing)

- **RDPS-0-REQ-1**: Browser shall operate fully offline without requiring remote connectivity → Assessment: RDPS-REQ-52
- **RDPS-0-REQ-2**: All user data shall be stored locally without remote synchronization → Assessment: RDPS-REQ-53
- **RDPS-0-REQ-3**: Browser shall not transmit telemetry, diagnostics, or usage data to remote servers → Assessment: RDPS-REQ-54
- **RDPS-0-REQ-4**: Browser shall function without degradation when network connectivity unavailable → Assessment: RDPS-REQ-55
- **RDPS-0-REQ-5**: No remote authentication or authorization services shall be required → Assessment: RDPS-REQ-56
- **RDPS-0-REQ-6**: Browser shall document all local-only operation capabilities and limitations → Assessment: RDPS-REQ-57
- **RDPS-0-REQ-7**: Users shall be informed that no data leaves the local system → Assessment: RDPS-REQ-58

#### RDPS-1 Requirements (Limited remote processing for non-sensitive data)

- **RDPS-1-REQ-1**: Browser shall document product functionality when RDPS connectivity unavailable → Assessment: RDPS-REQ-1
- **RDPS-1-REQ-2**: Browser shall define all data processed or stored in RDPS with data classification → Assessment: RDPS-REQ-2
- **RDPS-1-REQ-3**: Browser shall classify criticality of all RDPS-processed data → Assessment: RDPS-REQ-3
- **RDPS-1-REQ-4**: Browser shall encrypt all data transmissions to RDPS using TLS 1.3 or higher → Assessment: RDPS-REQ-4
- **RDPS-1-REQ-5**: Browser shall authenticate RDPS endpoints using certificate validation → Assessment: RDPS-REQ-5
- **RDPS-1-REQ-6**: Browser shall implement retry mechanisms with exponential backoff for RDPS failures → Assessment: RDPS-REQ-6
- **RDPS-1-REQ-7**: Browser shall cache critical data locally for offline operation → Assessment: RDPS-REQ-7
- **RDPS-1-REQ-8**: Browser shall implement secure authentication for RDPS access → Assessment: RDPS-REQ-8
- **RDPS-1-REQ-9**: Browser shall validate server certificates and enforce certificate pinning for RDPS → Assessment: RDPS-REQ-9
- **RDPS-1-REQ-10**: Browser shall implement timeout controls for RDPS connections → Assessment: RDPS-REQ-10
- **RDPS-1-REQ-11**: Browser shall log RDPS connectivity failures and errors → Assessment: RDPS-REQ-11
- **RDPS-1-REQ-12**: Browser shall gracefully degrade functionality when RDPS unavailable → Assessment: RDPS-REQ-12
- **RDPS-1-REQ-13**: Browser shall not expose sensitive authentication credentials to RDPS → Assessment: RDPS-REQ-13
- **RDPS-1-REQ-14**: Browser shall implement rate limiting for RDPS requests → Assessment: RDPS-REQ-14
- **RDPS-1-REQ-15**: Browser shall validate all data received from RDPS before processing → Assessment: RDPS-REQ-15

#### RDPS-2 Requirements (Extended remote processing with sensitive data)

- **RDPS-2-REQ-1**: All RDPS-1 requirements shall be implemented → Assessment: RDPS-REQ-59
- **RDPS-2-REQ-2**: Browser shall encrypt sensitive data at rest in RDPS storage → Assessment: RDPS-REQ-16
- **RDPS-2-REQ-3**: Browser shall implement mutual TLS authentication for RDPS connections → Assessment: RDPS-REQ-17
- **RDPS-2-REQ-4**: Browser shall maintain redundant copies of critical data for recovery → Assessment: RDPS-REQ-18
- **RDPS-2-REQ-5**: Browser shall support data recovery from backups with integrity verification → Assessment: RDPS-REQ-19
- **RDPS-2-REQ-6**: Browser shall implement data retention policies with secure deletion → Assessment: RDPS-REQ-20
- **RDPS-2-REQ-7**: Browser shall enforce access controls on RDPS data per-user and per-origin → Assessment: RDPS-REQ-21
- **RDPS-2-REQ-8**: Browser shall audit all RDPS access and modifications → Assessment: RDPS-REQ-22
- **RDPS-2-REQ-9**: Browser shall implement data integrity verification using cryptographic hashes → Assessment: RDPS-REQ-23
- **RDPS-2-REQ-10**: Browser shall protect against RDPS endpoint substitution attacks → Assessment: RDPS-REQ-24
- **RDPS-2-REQ-11**: Browser shall implement defense against replay attacks on RDPS communications → Assessment: RDPS-REQ-25
- **RDPS-2-REQ-12**: Browser shall enforce data minimization principles for RDPS transmissions → Assessment: RDPS-REQ-26
- **RDPS-2-REQ-13**: Browser shall provide user controls for RDPS data synchronization → Assessment: RDPS-REQ-27
- **RDPS-2-REQ-14**: Browser shall implement secure data export from RDPS for data portability → Assessment: RDPS-REQ-28
- **RDPS-2-REQ-15**: When user-configurable RDPS endpoints provided, all associated security settings shall be configurable → Assessment: RDPS-REQ-29
- **RDPS-2-REQ-16**: Browser shall verify RDPS service availability before critical operations → Assessment: RDPS-REQ-30
- **RDPS-2-REQ-17**: Browser shall implement connection pooling with security controls for RDPS → Assessment: RDPS-REQ-31
- **RDPS-2-REQ-18**: Browser shall protect RDPS authentication tokens from extraction and theft → Assessment: RDPS-REQ-32

#### RDPS-3 Requirements (Full remote processing with critical data)

- **RDPS-3-REQ-1**: All RDPS-2 requirements shall be implemented → Assessment: RDPS-REQ-60
- **RDPS-3-REQ-2**: Browser shall implement end-to-end encryption for all critical data in RDPS → Assessment: RDPS-REQ-33
- **RDPS-3-REQ-3**: Browser shall use hardware-backed key storage for RDPS encryption keys → Assessment: RDPS-REQ-34
- **RDPS-3-REQ-4**: Browser shall implement high-availability RDPS architecture with failover → Assessment: RDPS-REQ-35
- **RDPS-3-REQ-5**: Browser shall document and test RDPS disaster recovery procedures → Assessment: RDPS-REQ-36
- **RDPS-3-REQ-6**: Browser shall implement real-time RDPS integrity monitoring → Assessment: RDPS-REQ-37
- **RDPS-3-REQ-7**: Browser shall provide RDPS security event logging with SIEM integration → Assessment: RDPS-REQ-38
- **RDPS-3-REQ-8**: Browser shall enforce geographic data residency requirements when configured → Assessment: RDPS-REQ-39
- **RDPS-3-REQ-9**: Browser shall implement zero-trust architecture for RDPS access → Assessment: RDPS-REQ-40
- **RDPS-3-REQ-10**: Browser shall support regulatory compliance logging for RDPS operations → Assessment: RDPS-REQ-41
- **RDPS-3-REQ-11**: Browser shall implement automated RDPS security scanning and vulnerability detection → Assessment: RDPS-REQ-42
- **RDPS-3-REQ-12**: Browser shall provide cryptographic proof of RDPS data integrity → Assessment: RDPS-REQ-43
- **RDPS-3-REQ-13**: Browser shall implement secure multi-tenancy with data isolation in RDPS → Assessment: RDPS-REQ-44
- **RDPS-3-REQ-14**: Browser shall provide incident response procedures for RDPS breaches → Assessment: RDPS-REQ-45
- **RDPS-3-REQ-15**: Browser shall implement RDPS access revocation mechanisms → Assessment: RDPS-REQ-46
- **RDPS-3-REQ-16**: Browser shall provide transparency reporting for RDPS data access → Assessment: RDPS-REQ-47
- **RDPS-3-REQ-17**: Browser shall implement forward secrecy for RDPS communications → Assessment: RDPS-REQ-48
- **RDPS-3-REQ-18**: Browser shall provide user notification of RDPS security events → Assessment: RDPS-REQ-49
- **RDPS-3-REQ-19**: Browser shall document service discontinuation and data migration procedures → Assessment: RDPS-REQ-50
- **RDPS-3-REQ-20**: Enterprise administrators shall be able to configure RDPS security policies → Assessment: RDPS-REQ-51


# 6 Technical Security Assessments

This chapter provides detailed technical assessment procedures for verifying conformance with the security requirements specified in Chapter 5. Each assessment follows a structured methodology designed to produce objective, repeatable results suitable for third-party conformity assessment.

## 6.1 Domain and Origin Isolation Assessments

This section covers assessment procedures for requirements DOM-REQ-1 through DOM-REQ-12, addressing site isolation, origin-based security boundaries, cross-origin resource sharing, and related isolation mechanisms.

### Assessment: DOM-REQ-1 (Process-per-site isolation)

**Reference**: DOM-REQ-1 - Browser shall implement process-per-site isolation

**Given**: A conformant browser with site isolation capabilities (DOM-1 or higher)

**Task**: Verify that the browser enforces operating system-level process isolation between distinct sites to prevent compromise of one site from affecting other sites, and to enable OS-level security mechanisms (ASLR, sandboxing, memory protection) to provide defense-in-depth against web-based attacks.

**Verification**:

1. Open the browser and navigate to three distinct origins: https://example.com, https://test.com, and https://example.org → Create cross-origin iframes (example.com embedding test.com) and verify they run in separate processes
2. In each origin, open the browser's task manager or use platform process monitoring tools (Process Explorer on Windows, Activity Monitor on macOS, ps/top on Linux) → Confirm that each distinct site (eTLD+1) is allocated a separate renderer process
3. Identify the renderer processes associated with each origin → Verify that same-site navigations reuse the same renderer process
4. Record the Process IDs (PIDs) for each origin's renderer process → Check that cross-origin iframes are isolated in separate processes from their embedder
5. Navigate from https://example.com to https://example.com/page2 and verify the PID remains the same → Validate that process separation is maintained throughout the browser session
6. Navigate from https://example.com to https://different.example.com (different subdomain, same site) and verify the PID remains the same or changes according to documented site isolation policy → Review browser task manager or process monitoring tools to confirm distinct processes for distinct sites

**Pass Criteria**: All distinct sites use separate renderer processes AND cross-origin iframes are isolated in separate processes

**Fail Criteria**: Any two distinct sites share a renderer process OR cross-origin iframe runs in the same process as embedder

**Evidence**: Screenshots of browser task manager showing distinct PIDs for distinct sites, process tree diagrams, video recordings of process creation during navigation

**References**:

- Chromium Site Isolation Architecture: https://www.chromium.org/Home/chromium-security/site-isolation/
- Process Models for Web Browsers: https://www.chromium.org/developers/design-documents/process-models/
- Firefox Project Fission: https://wiki.mozilla.org/Project_Fission

### Assessment: DOM-REQ-2 (Cross-origin read blocking)

**Reference**: DOM-REQ-2 - Browser shall enforce Cross-Origin Read Blocking (CORB)

**Given**: A conformant browser with DOM-1 or higher capability

**Task**: Verify that the browser prevents attackers from using script/image/stylesheet tags to read sensitive cross-origin data (JSON, HTML, XML) that lacks CORS headers, protecting against Spectre-style attacks and cross-site data leakage where malicious pages attempt to load victim resources into contexts that could expose response data through side channels.

**Verification**:

1. Set up a test web server serving resources with various MIME types (HTML, JSON, XML, images, scripts) → Test edge cases: nosniff headers, ambiguous MIME types, empty responses
2. Create a test page at https://attacker.com that attempts to load resources from https://victim.com using various methods: → Confirm that JSON, HTML, and XML responses without CORS headers are blocked from cross-origin script contexts
   - `<script src="https://victim.com/sensitive.json">`
   - `<img src="https://victim.com/sensitive.json">`
   - `<link rel="stylesheet" href="https://victim.com/sensitive.html">`
   - `fetch()` requests without CORS headers
3. Configure https://victim.com to serve JSON/HTML/XML resources without CORS headers → Verify that browser console shows CORB warning messages with details of blocked resources
4. Monitor network traffic using browser DevTools to capture CORB decisions → Check that network panel shows resources blocked with CORB designation
5. Verify that cross-origin requests for JSON/HTML/XML are blocked when served with incorrect MIME types → Validate that legitimate cross-origin subresources (images, scripts with correct MIME types) load successfully
6. Verify that legitimate cross-origin image/script/CSS loads still succeed → Confirm that `X-Content-Type-Options: nosniff` is respected in CORB decisions

**Pass Criteria**: All cross-origin HTML/JSON/XML loads without CORS headers are blocked from script contexts AND browser logs CORB blocking events

**Fail Criteria**: Any JSON/HTML/XML resource is readable cross-origin without CORS headers OR no CORB enforcement is observable

**Evidence**: Browser console screenshots showing CORB warnings, network panel captures showing blocked resources, packet captures demonstrating data was fetched but not exposed to scripts, test server logs

**References**:

- CORB Specification: https://chromium.googlesource.com/chromium/src/+/master/services/network/cross_origin_read_blocking_explainer.md
- Fetch Metadata Request Headers: https://www.w3.org/TR/fetch-metadata/
- MIME Sniffing Standard: https://mimesniff.spec.whatwg.org/

### Assessment: DOM-REQ-3 (Strict origin policy enforcement)

**Reference**: DOM-REQ-3 - Browser shall prevent cross-origin DOM access without explicit consent

**Given**: A conformant browser with DOM-0 or higher capability

**Task**: Verify that the browser enforces the Same-Origin Policy to prevent scripts from one origin from reading or manipulating the DOM of another origin, protecting against cross-site scripting attacks where malicious sites attempt to steal sensitive data or hijack user sessions by accessing cross-origin window objects, documents, or storage.

**Verification**:

1. Create two test pages: https://site-a.com/test.html and https://site-b.com/test.html → Verify that `Location` object allows limited cross-origin access (href setter only) but not href getter
2. From site-a, open site-b in a new window using `window.open()` → Confirm that all cross-origin DOM access attempts throw SecurityError exceptions
3. Attempt cross-origin DOM access from site-a to site-b window: → Verify that browser console logs SecurityError with clear origin mismatch messages
   - `otherWindow.document` - attempt to access document
   - `otherWindow.localStorage` - attempt to access storage
   - `otherWindow.location.href = "javascript:..."` - attempt navigation hijacking
   - `otherWindow.frames[0]` - attempt to access frames
4. Verify that all cross-origin DOM access attempts throw SecurityError exceptions → Check that same-origin window access succeeds without errors
5. Test that same-origin window access succeeds → Validate that postMessage() works correctly for cross-origin communication
6. Test `window.postMessage()` as the legitimate cross-origin communication channel → Confirm that Location.href can be set cross-origin but not read

**Pass Criteria**: All cross-origin DOM property access attempts throw SecurityError AND postMessage provides functional cross-origin communication

**Fail Criteria**: Any cross-origin DOM property is readable/writable OR no exception is thrown

**Evidence**: Browser console screenshots showing SecurityError exceptions, video demonstration of test execution, automated test results from Web Platform Tests

**References**:

- HTML Standard - Cross-origin objects: https://html.spec.whatwg.org/multipage/browsers.html#cross-origin-objects
- Same-Origin Policy (MDN): https://developer.mozilla.org/en-US/docs/Web/Security/Same-origin_policy
- Web Platform Tests - Origin isolation: https://github.com/web-platform-tests/wpt/tree/master/html/browsers/origin

### Assessment: DOM-REQ-4 (CORS preflight enforcement)

**Reference**: DOM-REQ-4 - Browser shall enforce CORS preflight for non-simple requests

**Given**: A conformant browser with DOM-1 or higher capability

**Task**: Verify that the browser enforces CORS preflight checks for potentially dangerous cross-origin requests (non-simple methods, custom headers) to prevent attackers from triggering unauthorized state-changing operations on victim servers, ensuring that servers have an opportunity to reject requests before they execute and protecting against CSRF-style attacks that bypass simple request restrictions.

**Verification**:

1. Set up a test server that logs all incoming requests including OPTIONS requests → Test preflight caching behavior
2. Create test pages that make various fetch() requests to cross-origin servers: → Confirm that OPTIONS preflight requests are sent before all non-simple cross-origin requests
   - Simple requests (GET with simple headers)
   - Non-simple requests (PUT, DELETE, PATCH methods)
   - Requests with custom headers (X-Custom-Header)
   - Requests with credentials (cookies)
3. Monitor network traffic to verify preflight OPTIONS requests are sent before non-simple requests → Verify that actual requests only proceed after successful preflight response with matching CORS headers
4. Configure the server to respond with various CORS header combinations: → Check that browser blocks requests when preflight fails or returns incorrect headers
   - Correct CORS headers (Access-Control-Allow-Origin, Allow-Methods, Allow-Headers)
   - Missing CORS headers
   - Incorrect origin in CORS headers
   - Expired preflight cache (Access-Control-Max-Age: 0)
5. Verify that actual requests only proceed after successful preflight → Validate that preflight responses are cached according to Access-Control-Max-Age

**Pass Criteria**: All non-simple requests are preceded by OPTIONS preflight AND requests fail when preflight response lacks appropriate CORS headers

**Fail Criteria**: Non-simple requests proceed without preflight OR requests succeed despite missing CORS headers

**Evidence**: Network panel screenshots showing OPTIONS requests before actual requests, server logs demonstrating preflight sequence, packet captures with timing analysis

**References**:

- Fetch Standard - CORS protocol: https://fetch.spec.whatwg.org/#http-cors-protocol
- CORS (MDN): https://developer.mozilla.org/en-US/docs/Web/HTTP/CORS
- Preflight request specification: https://fetch.spec.whatwg.org/#cors-preflight-request

### Assessment: DOM-REQ-5 (Cookie SameSite attribute enforcement)

**Reference**: DOM-REQ-5 - Browser shall enforce SameSite cookie attribute

**Given**: A conformant browser with DOM-1 or higher capability

**Task**: Verify that the browser enforces SameSite cookie restrictions to prevent Cross-Site Request Forgery (CSRF) attacks where malicious sites trigger authenticated requests to victim applications by controlling when cookies are sent in cross-site contexts, with Strict preventing all cross-site transmission, Lax allowing safe top-level navigations, and None requiring explicit Secure flag.

**Verification**:

1. Set up two test domains: https://site-a.com and https://site-b.com → Verify that SameSite=None requires Secure attribute
2. Configure site-a to set cookies with various SameSite attributes: → Confirm that SameSite=Strict cookies are never sent in cross-site contexts
   - `Set-Cookie: session=abc123; SameSite=Strict; Secure`
   - `Set-Cookie: tracking=xyz789; SameSite=Lax; Secure`
   - `Set-Cookie: legacy=old; Secure` (no SameSite)
   - `Set-Cookie: none=test; SameSite=None; Secure`
3. From site-b, perform various cross-site requests to site-a: → Verify that SameSite=Lax cookies are sent only in top-level navigation (GET)
   - Top-level navigation (clicking link)
   - Embedded resources (images, iframes)
   - JavaScript fetch() POST request
   - Form submission (GET and POST)
4. Monitor network traffic to verify which cookies are sent in each scenario → Check that SameSite=None cookies are sent in all contexts but require Secure attribute
5. Test the default SameSite behavior for cookies without explicit attribute (should be Lax) → Validate that cookies without SameSite attribute default to Lax behavior

**Pass Criteria**: Cookie transmission matches SameSite attribute policy for all test cases AND default behavior is Lax

**Fail Criteria**: Any cookie is sent in violation of its SameSite policy OR SameSite=None works without Secure

**Evidence**: Network panel screenshots showing Cookie headers in different contexts, DevTools Application tab showing cookie attributes, test server logs of received cookies

**References**:

- RFC 6265bis - SameSite Cookies: https://datatracker.ietf.org/doc/html/draft-ietf-httpbis-rfc6265bis
- SameSite Cookies Explained (web.dev): https://web.dev/samesite-cookies-explained/
- Cookie SameSite attribute (MDN): https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Set-Cookie/SameSite

### Assessment: DOM-REQ-6 (Origin-bound storage isolation)

**Reference**: DOM-REQ-6 - Browser shall isolate localStorage and IndexedDB per origin

**Given**: A conformant browser with DOM-0 or higher capability

**Task**: Verify that the browser enforces complete storage isolation between origins to prevent malicious sites from reading sensitive user data (session tokens, personal information) stored by other applications, ensuring that origin boundaries (scheme, host, port) create impermeable barriers for localStorage and IndexedDB access.

**Verification**:

1. Create test pages at multiple origins: https://example.com, https://example.org, http://example.com, https://sub.example.com → Test port isolation (example.com:443 vs example.com:8080)
2. In each origin, write distinct data to localStorage: → Clear storage for one origin and verify other origins' storage is unaffected
   ```javascript
   localStorage.setItem('origin-test', location.origin);
   localStorage.setItem('timestamp', Date.now());
   ```
3. In each origin, create an IndexedDB database with a distinct name and store origin-specific data → Confirm that each origin has completely isolated localStorage namespace
4. Attempt to read localStorage and IndexedDB from each origin → Verify that each origin has completely isolated IndexedDB namespace
5. Verify that each origin only sees its own storage → Check that different subdomains cannot access each other's storage
6. Test subdomain isolation (example.com vs sub.example.com) → Validate that different protocols (http vs https) have separate storage
7. Test protocol isolation (https vs http) → Confirm that different ports have separate storage

**Pass Criteria**: No origin can read another origin's localStorage or IndexedDB AND all origin components (scheme, host, port) contribute to isolation boundary

**Fail Criteria**: Any cross-origin storage access succeeds OR incomplete origin matching (e.g., ignoring port)

**Evidence**: Browser DevTools Application tab screenshots showing storage contents per origin, console logs demonstrating isolation, automated test results

**References**:

- Web Storage API specification: https://html.spec.whatwg.org/multipage/webstorage.html
- IndexedDB API specification: https://w3c.github.io/IndexedDB/
- Origin definition: https://html.spec.whatwg.org/multipage/origin.html#concept-origin

### Assessment: DOM-REQ-7 (Frame sandboxing support)

**Reference**: DOM-REQ-7 - Browser shall support iframe sandbox attribute

**Given**: A conformant browser with DOM-1 or higher capability

**Task**: Verify that the browser implements iframe sandbox restrictions to mitigate risks from untrusted content by allowing developers to apply least-privilege principles to embedded frames, preventing malicious iframes from executing scripts, accessing parent windows, navigating the top frame, or abusing other dangerous capabilities unless explicitly permitted.

**Verification**:

1. Create test pages with iframes using various sandbox configurations: → Confirm that sandbox attribute restricts capabilities according to specified tokens
   ```html
   <iframe sandbox src="test.html"></iframe>
   <iframe sandbox="allow-scripts" src="test.html"></iframe>
   <iframe sandbox="allow-scripts allow-same-origin" src="test.html"></iframe>
   <iframe sandbox="allow-forms allow-popups" src="test.html"></iframe>
   ```
2. In each sandboxed iframe, attempt various actions: → Verify that scripts are blocked unless allow-scripts is present
   - JavaScript execution (alert, console.log)
   - Form submission
   - Opening popups (window.open)
   - Accessing parent window
   - Accessing localStorage
   - Top navigation (top.location = ...)
3. Verify that only explicitly allowed capabilities work → Check that same-origin access is blocked unless allow-same-origin is present
4. Test that sandbox="" (empty) applies strictest restrictions → Validate that sandboxed frames without allow-same-origin have unique opaque origin
5. Test CSP sandbox directive equivalence → Confirm that browser console logs security errors for blocked actions
6. Verify unique origin treatment for sandboxed iframes without allow-same-origin → Verify that CSP sandbox directive provides equivalent restrictions

**Pass Criteria**: All tested restrictions are enforced according to sandbox tokens AND browser logs security errors for blocked actions

**Fail Criteria**: Any capability works without corresponding allow-* token OR no restrictions are observed

**Evidence**: Browser console screenshots showing blocked actions, DevTools showing unique origin for sandboxed frames, test results demonstrating each sandbox token

**References**:

- HTML Standard - Sandboxing: https://html.spec.whatwg.org/multipage/iframe-embed-object.html#attr-iframe-sandbox
- CSP sandbox directive: https://www.w3.org/TR/CSP3/#directive-sandbox
- iframe sandbox (MDN): https://developer.mozilla.org/en-US/docs/Web/HTML/Element/iframe#attr-sandbox

### Assessment: DOM-REQ-8 (Opaque origin handling)

**Reference**: DOM-REQ-8 - Browser shall treat sandboxed and data: origins as opaque

**Given**: A conformant browser with DOM-0 or higher capability

**Task**: Verify that the browser treats sandboxed iframes and data: URLs as having opaque (unique, unguessable) origins that cannot access storage or credentials, preventing untrusted content from stealing sensitive data or establishing persistent state, while ensuring that each opaque origin is internally unique to prevent two untrusted contexts from communicating even though both serialize as "null".

**Verification**:

1. Create test scenarios for opaque origins:
   - Sandboxed iframe without allow-same-origin: `<iframe sandbox="allow-scripts" src="...">`
   - data: URL navigation: `window.open('data:text/html,<h1>Test</h1>')`
   - Blob URL: `URL.createObjectURL(new Blob(['...'], {type: 'text/html'}))`
2. In each opaque origin context, attempt to:
   - Access localStorage/sessionStorage (should throw SecurityError)
   - Access IndexedDB (should throw SecurityError)
   - Make fetch() requests (should succeed but not send credentials)
   - Access parent window (should be blocked for sandboxed frames)
3. Verify that opaque origins serialize as "null" in `window.origin`
4. Test that two distinct opaque origins cannot access each other even though both serialize as "null"
5. Verify that cookies are not sent/received from opaque origins
6. Confirm that opaque origins report window.origin as "null"
7. Verify that opaque origins cannot access localStorage, sessionStorage, or IndexedDB
8. Check that opaque origins do not send or receive cookies
9. Validate that each opaque origin is unique and cannot access other opaque origins
10. Confirm that fetch requests from opaque origins work but without credentials