threat-modeling.md

Threat Model Analysis for element-hq/element-android

Threat: Malicious Server Exploiting Parsing Vulnerabilities

• Description:
  • Attacker Action: A malicious Matrix server sends crafted Matrix events.
  • Method: Exploits parsing flaws in element-android's event processing logic.
  • Outcome: Application crashes (DoS) or potentially Remote Code Execution (RCE) within the application context due to vulnerabilities in element-android's code.
• Impact:
  • Application Instability: Crashes, making the application unusable.
  • Remote Code Execution (Severe Case): Full compromise of the application and device.
• Affected Component:
  • element-android Matrix Event Handling Module
  • element-android JSON Parsing Libraries
• Risk Severity: High (can be Critical if RCE is possible)
• Mitigation Strategies:
  • Developer:
    • Regularly update element-android to the latest version.
    • Report potential parsing vulnerabilities found in element-android to the library maintainers.
  • User:
    • Use reputable and trusted Matrix servers.
    • Keep the application updated.

Threat: Protocol Confusion Attacks

• Description:
  • Attacker Action: A malicious server sends unexpected Matrix protocol messages.
  • Method: Exploits weaknesses in element-android's Matrix protocol implementation and state management.
  • Outcome: Unexpected application behavior, bypass of security checks implemented within element-android, or disruption of communication handled by element-android.
• Impact:
  • Communication Disruption: Inability to send or receive messages via element-android.
  • Security Bypass: Circumvention of security features implemented in element-android.
  • Denial of Service: Application becomes unresponsive due to protocol handling issues in element-android.
• Affected Component:
  • element-android Matrix Client-Server Protocol Implementation
  • element-android State Management Module
• Risk Severity: High
• Mitigation Strategies:
  • Developer:
    • Ensure strict adherence to the Matrix protocol specification when integrating element-android.
    • Thoroughly test element-android's protocol handling.
    • Regularly update element-android.
  • User:
    • Use reputable and trusted Matrix servers.
    • Keep the application updated.

Threat: Insecure Handling of Server Responses leading to XSS

• Description:
  • Attacker Action: A malicious server sends malicious content in server responses.
  • Method: Exploits insufficient sanitization in element-android when processing server responses, specifically if rendered in UI components provided by element-android.
  • Outcome: Cross-Site Scripting (XSS) within the application context if element-android renders malicious HTML/JavaScript from server responses without proper sanitization.
• Impact:
  • Cross-Site Scripting (XSS): Execution of malicious scripts within the application, potentially stealing user data or performing actions on behalf of the user through vulnerabilities in element-android's rendering.
• Affected Component:
  • element-android Content Rendering Components (if server responses are rendered in UI provided by element-android)
  • element-android Input Sanitization Logic (or lack thereof)
• Risk Severity: High
• Mitigation Strategies:
  • Developer:
    • Strictly sanitize all data received from the Matrix server within the application using element-android.
    • If rendering server content using element-android components, ensure secure rendering mechanisms are used to prevent XSS.
    • Regularly update element-android.
  • User:
    • Be cautious about interacting with content from unknown Matrix servers.
    • Keep the application updated.

Threat: Key Compromise due to Insecure Storage in element-android

• Description:
  • Attacker Action: Gains access to the Android device and extracts encryption keys.
  • Method: Exploits insecure key storage mechanisms within element-android (e.g., if element-android itself stores keys insecurely).
  • Outcome: Compromise of E2EE keys managed by element-android, allowing decryption of messages and potential account takeover.
• Impact:
  • Confidentiality Breach: Exposure of encrypted communication history managed by element-android.
  • Account Impersonation: Ability to impersonate the user in Matrix communication managed by element-android.
• Affected Component:
  • element-android Key Management Module (Olm, Megolm key storage)
  • element-android Local Data Storage Mechanisms
• Risk Severity: Critical
• Mitigation Strategies:
  • Developer:
    • Mandatory: Ensure element-android is configured to utilize Android Keystore for secure key storage.
    • Verify that element-android does not store keys in insecure locations.
    • Regularly update element-android.
  • User:
    • Use strong device passwords/PINs.
    • Avoid rooting the device.

Threat: Vulnerabilities in Cryptographic Libraries used by element-android

• Description:
  • Attacker Action: Exploits vulnerabilities in crypto libraries used by element-android (libolm, vodozemac).
  • Method: Targets weaknesses in these libraries that element-android relies on for E2EE.
  • Outcome: Weakening or breaking of E2EE in applications using element-android, potentially allowing decryption of messages.
• Impact:
  • E2EE Breakdown: Loss of confidentiality of communication secured by element-android's E2EE.
  • Data Breach: Potential decryption of encrypted messages handled by element-android.
• Affected Component:
  • Cryptographic Libraries (libolm, vodozemac) as used by element-android
  • element-android E2EE Implementation
• Risk Severity: Critical
• Mitigation Strategies:
  • Developer:
    • Critical: Regularly update element-android to ensure it uses updated cryptographic libraries.
    • Monitor security advisories for cryptographic libraries used by element-android.
  • User:
    • Keep the application updated.

Threat: Implementation Flaws in E2EE Protocol Handling within element-android

• Description:
  • Attacker Action: Exploits bugs in element-android's E2EE protocol implementation (Olm, Megolm).
  • Method: Targets flaws in protocol logic, key exchange, session management, or encryption/decryption within element-android.
  • Outcome: Messages not properly encrypted by element-android, decryption by unauthorized parties, or other cryptographic weaknesses due to flaws in element-android's code.
• Impact:
  • E2EE Breakdown: Loss of confidentiality and integrity of encrypted communication handled by element-android.
  • Message Tampering: Potential for attackers to modify or forge messages within element-android's E2EE context.
• Affected Component:
  • element-android E2EE Protocol Implementation (Olm, Megolm modules)
  • element-android Key Exchange and Session Management Logic
• Risk Severity: Critical
• Mitigation Strategies:
  • Developer:
    • Critical: Thoroughly review and test the E2EE implementation in element-android integration.
    • Regularly update element-android to benefit from E2EE bug fixes.
  • User:
    • Keep the application updated.

Threat: Cross-Signing Vulnerabilities in element-android

• Description:
  • Attacker Action: Exploits flaws in element-android's cross-signing implementation.
  • Method: Targets weaknesses in device verification, key injection, or identity management related to cross-signing within element-android.
  • Outcome: Identity spoofing or compromise of device verification processes managed by element-android, weakening trust in device and user identities within the Matrix context of the application.
• Impact:
  • Identity Spoofing: An attacker can impersonate a legitimate user or device within the application using element-android.
  • Unauthorized Access: Gaining access to encrypted conversations by falsely verifying a malicious device through flaws in element-android's verification.
• Affected Component:
  • element-android Cross-Signing Implementation Module
  • element-android Device Verification Logic
• Risk Severity: High
• Mitigation Strategies:
  • Developer:
    • Carefully review and test the cross-signing implementation in element-android.
    • Regularly update element-android to benefit from cross-signing security fixes.
  • User:
    • Be vigilant when verifying new devices within the application.
    • Keep the application updated.

Threat: Session Key Reuse or Weak Session Key Generation in element-android

• Description:
  • Attacker Action: Exploits weaknesses in session key management within element-android.
  • Method: Targets reuse of session keys or predictable/weak session key generation algorithms within element-android's code.
  • Outcome: Weakening of encryption for messages handled by element-android, potentially allowing message decryption.
• Impact:
  • Weakened Encryption: Reduced security of E2EE for communication managed by element-android.
  • Potential Message Decryption: Increased risk of message content being exposed due to weakened encryption in element-android.
• Affected Component:
  • element-android Megolm Session Management Module
  • element-android Key Generation Functions
• Risk Severity: High
• Mitigation Strategies:
  • Developer:
    • Ensure proper session key rotation and secure key generation within element-android integration.
    • Regularly update element-android.
  • User:
    • Keep the application updated.

Threat: Insecure Key Backup and Recovery Mechanisms in element-android

• Description:
  • Attacker Action: Exploits vulnerabilities in key backup/recovery features provided by element-android.
  • Method: Targets weaknesses in backup storage, encryption of backups, or recovery process implemented by element-android.
  • Outcome: Unauthorized access to key backups managed by element-android, allowing decryption of encrypted messages.
• Impact:
  • Confidentiality Breach: Exposure of encrypted message history through compromised backups managed by element-android.
  • Data Loss (if recovery fails): Inability to recover keys and access encrypted messages if element-android's backup mechanisms are flawed.
• Affected Component:
  • element-android Key Backup and Recovery Module
  • element-android Backup Storage Mechanisms
• Risk Severity: High
• Mitigation Strategies:
  • Developer:
    • Implement secure key backup and recovery mechanisms when using element-android's features.
    • Regularly update element-android.
  • User:
    • Use strong passwords/passphrases for key backups if applicable in the application using element-android.

Threat: Misleading or Phishing UI Elements rendered by element-android

• Description:
  • Attacker Action: A malicious server influences UI elements rendered by element-android.
  • Method: Exploits vulnerabilities in how server responses are processed and rendered by element-android UI components, allowing for display of misleading or phishing content.
  • Outcome: Phishing attacks to steal user credentials or social engineering attacks through UI elements provided by element-android.
• Impact:
  • Credential Theft: Users may be tricked into entering credentials on fake prompts rendered by element-android.
  • Social Engineering: Users may be manipulated into revealing sensitive information due to misleading UI from element-android.
• Affected Component:
  • element-android UI Rendering Components
  • element-android Server Response Processing Logic (related to UI rendering)
• Risk Severity: High
• Mitigation Strategies:
  • Developer:
    • Carefully sanitize and validate content displayed in UI components provided by element-android, especially server-originated content.
    • Implement clear visual cues to distinguish legitimate UI elements from potentially malicious content rendered by element-android.
    • Regularly update element-android.
  • User:
    • Be wary of unexpected or suspicious UI elements within the application.
    • Verify the legitimacy of requests before providing information.

Threat: Unencrypted Local Storage of Message Database by element-android

• Description:
  • Attacker Action: Gains device access and accesses the message database.
  • Method: Exploits unencrypted storage of the message database by element-android on the device's file system.
  • Outcome: Exposure of message history and other sensitive Matrix data stored locally by element-android.
• Impact:
  • Confidentiality Breach: Exposure of message history and sensitive data managed by element-android.
  • Privacy Violation: Unauthorized access to user communication stored by element-android.
• Affected Component:
  • element-android Local Data Storage Module (Database, File System)
  • element-android Message Persistence Layer
• Risk Severity: High
• Mitigation Strategies:
  • Developer:
    • Mandatory: Ensure element-android is configured to encrypt the local message database at rest.
    • Verify that element-android does not store sensitive data unencrypted.
    • Regularly update element-android.
  • User:
    • Use strong device passwords/PINs and enable device encryption.
    • Avoid rooting the device.

Threat: Vulnerabilities in Third-Party Libraries causing issues via element-android

• Description:
  • Attacker Action: Exploits vulnerabilities in third-party libraries used by element-android.
  • Method: Targets weaknesses in dependencies that are integrated into element-android.
  • Outcome: Range of impacts depending on the vulnerability, affecting applications using element-android. Can include RCE, DoS, or information disclosure through element-android.
• Impact:
  • Varies: Impact depends on the specific vulnerability and affected library, realized through the application's use of element-android. Can be critical like RCE.
  • Application Instability: Crashes or unexpected behavior in applications using element-android.
  • Security Breach: Potential for data theft or system compromise in applications using element-android.
• Affected Component:
  • Third-Party Libraries (dependencies of element-android)
  • Any element-android module using vulnerable libraries
• Risk Severity: High (can be Critical depending on the vulnerability)
• Mitigation Strategies:
  • Developer:
    • Critical: Regularly update element-android to ensure it includes updated third-party libraries.
    • Monitor security advisories for dependencies of element-android.
  • User:
    • Keep the application updated.

Threat: Supply Chain Attacks on Dependencies of element-android

• Description:
  • Attacker Action: Compromises a third-party dependency used by element-android.
  • Method: Injects malicious code into a dependency package that element-android relies upon.
  • Outcome: Introduction of malicious code into element-android, and consequently into applications using it, potentially leading to data theft or malware installation in applications using element-android.
• Impact:
  • Malware Infection: Introduction of malicious code into applications using element-android.
  • Data Theft: Stealing user data from applications using element-android.
  • System Compromise: Potential for attackers to gain control of user devices running applications using compromised element-android.
• Affected Component:
  • Third-Party Libraries (dependencies of element-android)
  • element-android build and dependency management processes
• Risk Severity: High to Critical
• Mitigation Strategies:
  • Developer:
    • Use dependency verification mechanisms when building with element-android.
    • Use reputable dependency repositories for element-android and its dependencies.
    • Regularly update element-android.
  • User:
    • Keep the application updated.
    • Install applications from trusted sources.