Skip to content

Latest commit

 

History

History
129 lines (100 loc) · 7.76 KB

attack-tree.md

File metadata and controls

129 lines (100 loc) · 7.76 KB

Attack Tree Analysis for signalapp/signal-server

Objective: Deanonymize Users, Intercept Messages, or Disrupt Service [CRITICAL]

Attack Tree Visualization

[Deanonymize Users, Intercept Messages, or Disrupt Service] [CRITICAL] /
/
[Compromise Server-Side Logic] [Exploit Client-Server Interaction Vulnerabilities] / |
/ |
[Eavesdrop] [Man-in-the-] [Compromise] [Unencrypted] [Middle] [Client-Side] [Traffic] [Server] [Implementation] | | | [Intercept HTTP/2] [Compromise Server] [Exploit Weak] [Connections] [CRITICAL] [CRITICAL] [Crypto in Client] / [CRITICAL] / | [Exploit Server] [Supply Chain Attack] [Vulnerabilities] [on Dependencies][CRITICAL] | [Tamper with Server Code][CRITICAL]

Attack Tree Path: Deanonymize Users, Intercept Messages, or Disrupt Service

  • This is the overarching attacker goal and is inherently critical. Success in any of these objectives represents a significant security breach.

Attack Tree Path: Exploit Client-Server Interaction Vulnerabilities

This is a high-level category encompassing several critical attack vectors.

Attack Tree Path: Eavesdrop on Unencrypted Traffic

Attack Tree Path: Intercept HTTP/2 Connections

  • Threat: An attacker intercepts and decrypts communication between the client and server. This typically requires breaking or bypassing TLS encryption.
  • Mitigation: Use strong TLS configurations (TLS 1.3), certificate pinning, HSTS, and regularly update TLS libraries.
  • Likelihood: Very Low (if TLS is properly configured)
  • Impact: Very High (complete compromise of communication)
  • Effort: High (requires breaking TLS)
  • Skill Level: Expert
  • Detection Difficulty: Very Hard (if TLS is broken, detection is unlikely)

Attack Tree Path: Man-in-the-Middle (MitM)

Attack Tree Path: Compromise Server

  • Threat: An attacker gains full control of the Signal Server, allowing them to intercept, modify, or block any communication.
  • Mitigation: Strong physical security, regular patching, intrusion detection/prevention systems, strong access controls, secure development lifecycle (SDL).
  • Likelihood: Very Low (requires significant resources and expertise)
  • Impact: Very High (complete compromise of the system)
  • Effort: Very High
  • Skill Level: Expert
  • Detection Difficulty: Hard (requires sophisticated intrusion detection)
  • [Exploit Server Vulnerabilities]
    • Threat: An attacker exploits a vulnerability in the server software (operating system, web server, Signal Server code itself) to gain unauthorized access.
    • Mitigation: Regular security patching, vulnerability scanning, penetration testing, secure coding practices.
    • Likelihood: Low (if server is regularly patched)
    • Impact: Very High (complete compromise)
    • Effort: High
    • Skill Level: Expert
    • Detection Difficulty: Medium (intrusion detection systems)

Attack Tree Path: Exploit Server Vulnerabilities

  • Threat: An attacker exploits a vulnerability in the server software (operating system, web server, Signal Server code itself) to gain unauthorized access.
    • Mitigation: Regular security patching, vulnerability scanning, penetration testing, secure coding practices.
    • Likelihood: Low (if server is regularly patched)
    • Impact: Very High (complete compromise)
    • Effort: High
    • Skill Level: Expert
    • Detection Difficulty: Medium (intrusion detection systems)

Attack Tree Path: Compromise Client-Side Implementation

Attack Tree Path: Exploit Weak Crypto in Client

  • Threat: The client application (not the Signal Server itself) has vulnerabilities in its cryptographic implementation, allowing an attacker to decrypt messages or impersonate users.
  • Mitigation: The client must use strong, well-vetted cryptographic libraries, follow best practices for key management, and undergo regular security audits.
  • Likelihood: Low to Medium (depends on the client's security)
  • Impact: Very High (message decryption, impersonation)
  • Effort: High (requires finding and exploiting crypto vulnerabilities)
  • Skill Level: Expert
  • Detection Difficulty: Very Hard (requires analyzing the client's code)
  • [Supply Chain Attack on Dependencies] [CRITICAL]
    • Threat: An attacker compromises a third-party library or component used by the Signal Server, injecting malicious code.
    • Mitigation: Use a Software Bill of Materials (SBOM), dependency pinning, checksum verification, regular dependency audits, consider using a private package repository.
    • Likelihood: Low (but increasing in frequency)
    • Impact: Very High (complete compromise of the system)
    • Effort: High (requires compromising a trusted dependency)
    • Skill Level: Expert
    • Detection Difficulty: Very Hard (requires sophisticated supply chain security measures)
  • [Tamper with Server Code] [CRITICAL]
    • Threat: An attacker gains unauthorized access to modify the server's source code directly.
    • Mitigation: Strict access control to the codebase, code signing, integrity checks, robust code review process, secure CI/CD pipeline.
    • Likelihood: Very Low
    • Impact: Very High
    • Effort: High
    • Skill Level: Expert
    • Detection Difficulty: Medium

Attack Tree Path: Supply Chain Attack on Dependencies

  • Threat: An attacker compromises a third-party library or component used by the Signal Server, injecting malicious code.
    • Mitigation: Use a Software Bill of Materials (SBOM), dependency pinning, checksum verification, regular dependency audits, consider using a private package repository.
    • Likelihood: Low (but increasing in frequency)
    • Impact: Very High (complete compromise of the system)
    • Effort: High (requires compromising a trusted dependency)
    • Skill Level: Expert
    • Detection Difficulty: Very Hard (requires sophisticated supply chain security measures)

Attack Tree Path: Tamper with Server Code

  • Threat: An attacker gains unauthorized access to modify the server's source code directly.
    • Mitigation: Strict access control to the codebase, code signing, integrity checks, robust code review process, secure CI/CD pipeline.
    • Likelihood: Very Low
    • Impact: Very High
    • Effort: High
    • Skill Level: Expert
    • Detection Difficulty: Medium