threat-modeling.md

Threat Model Analysis for matrix-org/synapse

Threat: Message Spoofing

• Threat: Message Spoofing
• Description: An attacker crafts a malicious Matrix message and manipulates its origin information to appear as if it came from a trusted user or server. This could involve forging signatures or exploiting weaknesses in message origin validation within Synapse's event processing logic. The attacker might use this to spread misinformation, initiate social engineering attacks, or disrupt communication by impersonating administrators.
• Impact: Loss of trust in communication, successful social engineering attacks against users, spread of misinformation, reputational damage to the platform.
• Affected Synapse Component: Event processing module, message signing and verification functions, federation handling.
• Risk Severity: High
• Mitigation Strategies:
  • Ensure Synapse is running the latest stable version with up-to-date Matrix protocol implementations.
  • Regularly review Synapse security advisories related to protocol handling and apply necessary patches.
  • Implement robust message verification and signature checks within Synapse configuration.

Threat: Denial of Service (DoS) via Protocol Exploits

• Threat: Denial of Service (DoS) via Protocol Exploits
• Description: An attacker sends a flood of specially crafted Matrix protocol messages designed to exploit vulnerabilities in Synapse's message processing. These messages could target resource-intensive parsing logic, state management functions, or federation handling routines, causing the Synapse server to become overloaded, crash, or become unresponsive. The attacker aims to disrupt service availability for legitimate users.
• Impact: Service unavailability for users, disruption of communication, resource exhaustion leading to server instability, potential financial losses due to downtime.
• Affected Synapse Component: Event parsing module, state management functions, federation handling components, message queue.
• Risk Severity: High
• Mitigation Strategies:
  • Implement robust input validation and sanitization for all incoming Matrix protocol messages.
  • Apply rate limiting on message processing at various levels (e.g., per user, per room, globally).
  • Monitor server resource usage (CPU, memory, network) for anomalies and implement alerts for unusual spikes.
  • Keep Synapse updated with the latest security patches and bug fixes.

Threat: Malicious Federated Server Exploitation

• Threat: Malicious Federated Server Exploitation
• Description: A compromised or intentionally malicious federated Matrix server attempts to exploit vulnerabilities in Synapse through standard federation interactions. This could involve sending crafted malicious messages via federation APIs, exploiting weaknesses in federation event processing, or attempting to inject malicious data into Synapse's state database through federation mechanisms. The attacker aims to compromise Synapse, steal data, or disrupt service.
• Impact: Data breaches, server compromise of the Synapse instance, service disruption, propagation of malicious content to Synapse users, reputational damage.
• Affected Synapse Component: Federation API endpoints, federation event processing module, state management functions, database interaction during federation.
• Risk Severity: High
• Mitigation Strategies:
  • Implement robust federation input validation and sanitization for all data received from federated servers.
  • Limit trust in federated servers by implementing federation allow-lists or stricter federation policies in Synapse configuration.
  • Monitor federation traffic for suspicious activity.
  • Regularly review and update federation security configurations and policies.

Threat: Data Leakage via Federation

• Threat: Data Leakage via Federation
• Description: Sensitive data, such as private messages, user information, or room metadata, is unintentionally or maliciously exposed to federated servers during normal federation operations. This could be due to misconfigurations in federation settings, vulnerabilities in federation data handling logic, or malicious actions by administrators or compromised servers on the federated network. The attacker might be a malicious federated server operator or an attacker who has compromised a federated server.
• Impact: Privacy breaches for users, loss of data confidentiality, reputational damage, potential compliance violations (e.g., GDPR).
• Affected Synapse Component: Federation data sharing logic, room visibility and access control mechanisms, federation event handling, data serialization for federation.
• Risk Severity: High
• Mitigation Strategies:
  • Carefully configure federation settings to strictly control the types and scope of data shared with federated servers.
  • Implement strict access control policies for federated rooms and data to minimize exposure.
  • Regularly audit federation configurations and data exposure risks.
  • Consider enabling end-to-end encryption (E2EE) for sensitive communications.

Threat: Federation Man-in-the-Middle (MitM) Attacks

• Threat: Federation Man-in-the-Middle (MitM) Attacks
• Description: An attacker intercepts federation traffic between Synapse and other Matrix servers. This could be achieved by compromising network infrastructure or exploiting weak encryption. The attacker can then eavesdrop on federated communications, modify messages in transit to manipulate conversations or inject malicious content, or impersonate either Synapse or the federated server to gain unauthorized access or disrupt communication.
• Impact: Data breaches due to eavesdropping, message manipulation leading to misinformation or disruption, loss of data integrity, service disruption due to impersonation or manipulation.
• Affected Synapse Component: Federation communication channels, server-to-server TLS connections, federation data exchange.
• Risk Severity: High
• Mitigation Strategies:
  • Enforce TLS encryption for all federation traffic (HTTPS).
  • Implement mutual TLS (mTLS) for stronger server authentication during federation if feasible.
  • Monitor federation connections for suspicious activity.

Threat: Account Takeover (Matrix Account)

• Threat: Account Takeover (Matrix Account)
• Description: An attacker gains unauthorized access to a Matrix user account managed by Synapse. This could be through credential stuffing attacks (using leaked credentials from other services), phishing attacks targeting user passwords, or exploiting vulnerabilities in Synapse's authentication mechanisms. Once in control, the attacker can access user data, impersonate the user, and perform malicious actions within the Matrix ecosystem.
• Impact: Unauthorized access to user data (private messages, contacts, etc.), impersonation of the user, malicious activities performed under the compromised account (spamming, social engineering, data exfiltration), data breaches.
• Affected Synapse Component: Authentication module, password management functions, session management, user account database.
• Risk Severity: High
• Mitigation Strategies:
  • Enforce strong password policies for user accounts.
  • Implement multi-factor authentication (MFA).
  • Regularly audit user accounts and access logs for suspicious login attempts.

Threat: Device Verification Bypass

• Threat: Device Verification Bypass
• Description: An attacker attempts to bypass Synapse's device verification mechanisms, which are designed to ensure that new devices accessing an account are authorized by the user. This could involve exploiting vulnerabilities in the device verification process itself, such as flaws in key exchange, signature verification, or session management related to device verification. A successful bypass allows the attacker to gain unauthorized access to a user's account from a new device without proper authorization.
• Impact: Unauthorized access to user account from attacker's device, data breaches, impersonation, circumvention of security measures designed to protect user accounts.
• Affected Synapse Component: Device verification module, key management functions, session management related to device verification, client-server API for device verification.
• Risk Severity: High
• Mitigation Strategies:
  • Implement robust and well-tested device verification mechanisms adhering to Matrix protocol specifications.
  • Regularly review and update device verification logic.
  • Monitor for suspicious device verification attempts.

Threat: Room Access Control Bypass

• Threat: Room Access Control Bypass
• Description: An attacker attempts to bypass Synapse's room access control mechanisms to gain unauthorized access to private or restricted Matrix rooms or spaces. This could involve exploiting vulnerabilities in room permission management logic, membership handling functions, or event authorization checks. The attacker might try to manipulate room state events, exploit weaknesses in permission inheritance, or find flaws in the authorization process to gain unauthorized entry or access to room content.
• Impact: Unauthorized access to sensitive information within private rooms, privacy breaches, data confidentiality loss, potential exposure of confidential discussions or data.
• Affected Synapse Component: Room access control module, permission management functions, membership handling, event authorization logic, state event processing.
• Risk Severity: High
• Mitigation Strategies:
  • Implement strict and well-defined room access control policies based on Matrix room access control mechanisms.
  • Regularly audit room permissions and membership configurations.
  • Monitor room access logs for unauthorized access attempts.

Threat: Data Breach (Matrix Data Storage)

• Threat: Data Breach (Matrix Data Storage)
• Description: An attacker gains unauthorized access to Synapse's data storage, which typically includes a database and potentially a file system for media. This could be achieved through various means, such as exploiting server vulnerabilities, misconfigurations in data storage security, or insider threats. Access to the data storage allows the attacker to directly access all Matrix data, including messages, user profiles, room state, and potentially media files.
• Impact: Massive data breach, privacy violations for all users, loss of data confidentiality, reputational damage, severe compliance violations, potential legal repercussions.
• Affected Synapse Component: Database server, file system storage for media, server infrastructure hosting Synapse and data storage.
• Risk Severity: Critical
• Mitigation Strategies:
  • Implement strong access controls for data storage systems.
  • Encrypt sensitive data at rest within the database and file system.
  • Regularly audit data storage security configurations and access controls.
  • Secure the underlying infrastructure hosting Synapse and its data storage.

Threat: Remote Code Execution (RCE) in Synapse

• Threat: Remote Code Execution (RCE) in Synapse
• Description: A vulnerability exists in Synapse's code that allows an attacker to execute arbitrary code on the Synapse server remotely. This could be triggered by sending specially crafted Matrix messages, exploiting parsing vulnerabilities in message processing, insecure deserialization of data, or other code execution flaws within Synapse's codebase. Successful RCE gives the attacker complete control over the Synapse server.
• Impact: Full server compromise, complete loss of confidentiality, integrity, and availability of the Synapse server and all hosted data, data breaches, service disruption, potential for further attacks on internal networks.
• Affected Synapse Component: Any part of Synapse codebase with vulnerabilities, potentially event parsing module, media processing, API endpoints, dependency libraries.
• Risk Severity: Critical
• Mitigation Strategies:
  • Regularly update Synapse to the latest stable version with security patches and bug fixes.
  • Conduct security code reviews and penetration testing.
  • Implement robust input validation and sanitization.
  • Follow secure coding practices.

Threat: Exploiting Vulnerable Dependencies

• Threat: Exploiting Vulnerable Dependencies
• Description: Synapse relies on various third-party libraries and dependencies (primarily Python packages). Vulnerabilities discovered in these dependencies can directly impact Synapse's security. Attackers can exploit known vulnerabilities in these libraries if Synapse uses vulnerable versions. This could lead to various impacts depending on the nature of the dependency vulnerability, ranging from DoS to RCE.
• Impact: Server compromise, data breaches, service disruption, depending on the severity and nature of the vulnerability in the dependency.
• Affected Synapse Component: All Synapse components that utilize vulnerable dependencies.
• Risk Severity: Varies (can be Critical or High depending on the dependency vulnerability)
• Mitigation Strategies:
  • Regularly scan Synapse's dependencies for known vulnerabilities using vulnerability scanning tools.
  • Keep dependencies updated to the latest secure versions.
  • Implement dependency management best practices.

Threat: Media Processing Vulnerabilities

• Threat: Media Processing Vulnerabilities
• Description: Vulnerabilities exist in media processing libraries used by Synapse (e.g., image libraries like Pillow, video codecs, document processing libraries). Attackers can exploit these vulnerabilities by uploading crafted media files that trigger these vulnerabilities when processed by Synapse. Exploitation could lead to server-side vulnerabilities like Remote Code Execution (RCE), Denial of Service (DoS), or information disclosure.
• Impact: Server compromise due to RCE, service disruption due to DoS, data breaches if information disclosure vulnerabilities are exploited, reputational damage.
• Affected Synapse Component: Media processing functions, dependency libraries used for media processing (e.g., Pillow, etc.).
• Risk Severity: High
• Mitigation Strategies:
  • Use secure and well-maintained media processing libraries.
  • Keep media processing libraries updated to the latest versions with security patches.
  • Implement input validation and sanitization for media files before processing them.