threat-modeling.md

Threat Model Analysis for element-hq/element-web

Threat: Cross-Site Scripting (XSS) in Message Rendering

• Description: An attacker crafts a malicious message containing JavaScript code and sends it to a user. Element Web, when rendering this message, fails to properly sanitize the input, causing the malicious script to execute in the victim's browser. This could be achieved through direct messaging, room messages, or profile information.
• Impact: Account compromise (session hijacking, stealing credentials), data theft (accessing local storage, cookies), redirection to malicious websites, defacement of the Element Web interface, sending messages as the victim.
• Element Web Component Affected: Message rendering module, potentially within the rich text editor or message display components.
• Risk Severity: High
• Mitigation Strategies:
  • Keep Element Web updated to the latest version, as updates often include XSS vulnerability fixes.
  • Implement a strong Content Security Policy (CSP) to restrict the origins from which scripts can be loaded and executed.
  • If you are extending or modifying Element Web's message rendering, ensure proper input sanitization and output encoding.

Threat: Dependency Vulnerability Exploitation (e.g., in a library used by Element Web)

• Description: Element Web relies on numerous third-party JavaScript libraries. An attacker identifies a known vulnerability in one of these dependencies (e.g., a vulnerable version of lodash, react, etc.). They then craft an exploit that leverages this vulnerability, potentially through a malicious message, interaction with a specific Element Web feature, or by targeting a publicly exposed Element Web endpoint if applicable.
• Impact: Depending on the vulnerability, impacts can range from XSS to Remote Code Execution (RCE) on the client's machine, leading to account compromise, data theft, or complete control over the user's browser session.
• Element Web Component Affected: Dependency management system, potentially affecting various modules that rely on the vulnerable library.
• Risk Severity: High to Critical (depending on the specific vulnerability)
• Mitigation Strategies:
  • Regularly audit and update Element Web's dependencies using dependency scanning tools (e.g., npm audit, yarn audit, Snyk).
  • Implement a process for promptly updating Element Web and its dependencies when security advisories are released.
  • Consider using Software Composition Analysis (SCA) tools to continuously monitor dependencies for vulnerabilities.

Threat: Prototype Pollution leading to Privilege Escalation

• Description: An attacker exploits a prototype pollution vulnerability within Element Web or one of its dependencies. By manipulating JavaScript object prototypes, they inject malicious properties that can alter the behavior of Element Web. This could be achieved through crafted input data, URL parameters, or by exploiting a vulnerability in how Element Web processes data. This could lead to bypassing access controls or gaining elevated privileges within the application.
• Impact: Privilege escalation, unauthorized access to features or data, potentially leading to account takeover or further exploitation.
• Element Web Component Affected: Core JavaScript runtime environment, potentially affecting various modules that rely on object properties and inheritance.
• Risk Severity: Medium to High (can be considered High if exploit leads to significant privilege escalation)
• Mitigation Strategies:
  • Keep Element Web and its dependencies updated, as prototype pollution vulnerabilities are being actively researched and patched.
  • Implement robust input validation and sanitization to prevent injection of malicious data that could trigger prototype pollution.
  • Be mindful of code patterns that might be susceptible to prototype pollution during any custom development or integration with Element Web.

Threat: End-to-End Encryption (E2EE) Implementation Flaws

• Description: Element Web implements Matrix's E2EE. Vulnerabilities in the cryptographic implementation within Element Web (e.g., in key exchange, encryption/decryption algorithms, or key management) could be exploited by a sophisticated attacker to decrypt encrypted messages without authorization. This could involve side-channel attacks, flaws in the cryptographic libraries used, or logical errors in the implementation.
• Impact: Loss of confidentiality of encrypted communications, exposure of sensitive message content.
• Element Web Component Affected: E2EE modules, including cryptographic libraries, key management functions, and message encryption/decryption logic.
• Risk Severity: Critical
• Mitigation Strategies:
  • Trust in the security audits and reviews conducted by the Element team and the Matrix community on the E2EE implementation.
  • Keep Element Web updated to benefit from security fixes and improvements in the E2EE implementation.
  • Report any suspected encryption vulnerabilities to the Element security team through their responsible disclosure channels.
  • Users should verify device cross-signing and key backup to ensure proper key management and recovery.

Threat: Using Outdated Element Web Version with Known Vulnerabilities

• Description: Failing to regularly update Element Web to the latest version means you are running a version that may contain known security vulnerabilities that have been publicly disclosed and patched in newer releases. Attackers can target these known vulnerabilities to compromise your application or users.
• Impact: Exposure to known vulnerabilities, increased risk of exploitation, potential data breaches, account compromise, and other impacts depending on the specific vulnerabilities present in the outdated version.
• Element Web Component Affected: Entire Element Web application, as vulnerabilities can exist in various modules.
• Risk Severity: High to Critical (depending on the age and severity of vulnerabilities in the outdated version)
• Mitigation Strategies:
  • Establish a process for regularly updating Element Web to the latest stable version.
  • Monitor Element Web's security advisories, release notes, and community channels for announcements of security updates.
  • Implement automated update mechanisms where possible to ensure timely patching of vulnerabilities.
  • Prioritize security updates and apply them promptly.