attack-tree.md

Attack Tree Analysis for zeromq/zeromq4-x

Objective: To compromise an application that uses ZeroMQ by exploiting weaknesses or vulnerabilities within the project itself, achieving at least one of: Denial of Service, Information Disclosure, Remote Code Execution, or Message Manipulation/Spoofing.

Attack Tree Visualization

[Attacker's Goal: Compromise Application via ZeroMQ] ├── [2. Information Disclosure] [CN] │ └── [2.1 Eavesdropping (Unencrypted Communication)] [HR] [CN] │ └── Intercept ZeroMQ messages transmitted over an unencrypted channel... [HR] ├── [3. Remote Code Execution (RCE)] [CN] │ ├── [3.2 Format String Vulnerability] [HR] │ │ └── If the application uses ZeroMQ data in format string functions... [HR] │ └── [3.3 Deserialization Vulnerability] [HR] │ └── If the application uses an unsafe deserialization method... [HR] └── [4. Message Manipulation/Spoofing] [CN] ├── [4.1 Man-in-the-Middle (MitM) Attack] [HR] [CN] │ └── Intercept and modify ZeroMQ messages between two communicating parties... [HR] ├── [4.3 Message Injection] [HR] │ └── Inject forged ZeroMQ messages into the communication stream... [HR] └── [4.4 Message Tampering] [HR] └── Modify the content of legitimate ZeroMQ messages... [HR] └── [1. Denial of Service (DoS)] └── [1.1 Resource Exhaustion] └── [1.1.2 Memory Exhaustion] [HR] └── Send extremely large messages that consume excessive memory... [HR]

Attack Tree Path: 2. Information Disclosure

• 2.1 Eavesdropping (Unencrypted Communication) [High-Risk Path] [Critical Node]
  • Description: The attacker intercepts ZeroMQ messages transmitted over a network without encryption. This is possible if the application uses plain TCP, IPC, or inproc without enabling ZeroMQ's curve security or another encryption mechanism.
  • Attack Vector:
    • The application uses a ZeroMQ socket type (e.g., REQ, REP, PUB, SUB) over an unencrypted transport (e.g., tcp://).
    • The attacker gains access to the network between the communicating parties (e.g., through network sniffing, compromised router, ARP spoofing).
    • The attacker uses a network analysis tool (e.g., Wireshark, tcpdump) to capture the raw network traffic.
    • The attacker can read the contents of the ZeroMQ messages, potentially exposing sensitive data.
  • Likelihood: High (if encryption is not used)
  • Impact: Very High (complete exposure of sensitive data)
  • Effort: Low
  • Skill Level: Novice
  • Detection Difficulty: Hard (without encryption, eavesdropping is often undetectable)
  • Mitigation: Use ZeroMQ's curve security mechanism. This provides authenticated encryption, preventing eavesdropping. Do not rely on plain TCP, IPC, or inproc for sensitive data.

Attack Tree Path: 3. Remote Code Execution (RCE)

• 3.2 Format String Vulnerability [High-Risk Path]

  • Description: The application uses data received via ZeroMQ in a format string function (e.g., fmt.Sprintf in Go, printf in C) without proper sanitization. This allows an attacker to inject format string specifiers, potentially leading to arbitrary code execution.
  • Attack Vector:
    • The application receives data from a ZeroMQ socket.
    • The application uses this data, without sanitization, as an argument to a format string function.
    • The attacker crafts a malicious ZeroMQ message containing format string specifiers (e.g., %x, %n, %s).
    • When the application processes the malicious message, the format string vulnerability is triggered, allowing the attacker to read from or write to arbitrary memory locations, potentially leading to code execution.
  • Likelihood: Medium (if input is not properly sanitized) / Low (if the application avoids using unsanitized input in format strings)
  • Impact: Very High (complete system compromise)
  • Effort: Medium
  • Skill Level: Intermediate to Advanced
  • Detection Difficulty: Medium (static analysis tools can often detect format string vulnerabilities)
  • Mitigation: Never use unsanitized user input (including data received via ZeroMQ) in format string functions. Use safer alternatives or explicitly sanitize the input.

• 3.3 Deserialization Vulnerability [High-Risk Path]

  • Description: The application uses an unsafe deserialization method (e.g., encoding/gob in Go without type checking, Python's pickle) on data received via ZeroMQ. This allows an attacker to inject malicious serialized data, which, when deserialized, can execute arbitrary code.
  • Attack Vector:
    • The application receives data from a ZeroMQ socket.
    • The application deserializes this data using an unsafe method.
    • The attacker crafts a malicious ZeroMQ message containing specially crafted serialized data.
    • When the application deserializes the malicious message, the deserialization vulnerability is triggered, allowing the attacker to execute arbitrary code.
  • Likelihood: Medium to High (if unsafe deserialization is used) / Low (if secure deserialization is used)
  • Impact: Very High (complete system compromise)
  • Effort: Medium
  • Skill Level: Intermediate to Advanced
  • Detection Difficulty: Medium (requires careful analysis of deserialization logic)
  • Mitigation: Avoid unsafe deserialization. If you must deserialize data received via ZeroMQ, use a secure deserialization library or method that performs type checking and whitelisting. Consider using data formats like JSON or Protocol Buffers, which are less prone to deserialization vulnerabilities.

Attack Tree Path: 4. Message Manipulation/Spoofing

• 4.1 Man-in-the-Middle (MitM) Attack [High-Risk Path] [Critical Node]

  • Description: The attacker intercepts and modifies ZeroMQ messages between two communicating parties without their knowledge. This is possible if the communication is not encrypted and authenticated.
  • Attack Vector:
    • The application uses a ZeroMQ socket over an unencrypted transport.
    • The attacker gains access to the network between the communicating parties (e.g., through ARP spoofing, DNS poisoning, compromised router).
    • The attacker intercepts the ZeroMQ messages.
    • The attacker can modify the messages, inject new messages, or drop messages.
    • The receiving party is unaware that the messages have been tampered with.
  • Likelihood: High (if encryption is not used)
  • Impact: Very High (complete control over communication)
  • Effort: Medium
  • Skill Level: Intermediate
  • Detection Difficulty: Hard (without encryption, MitM is often undetectable)
  • Mitigation: Use ZeroMQ's curve security mechanism. This provides authenticated encryption, preventing MitM attacks.

• 4.3 Message Injection [High-Risk Path]

  • Description: The attacker injects forged ZeroMQ messages into the communication stream, potentially bypassing authentication or authorization checks.
  • Attack Vector:
    • The application uses a ZeroMQ socket without authentication.
    • The attacker gains access to the network or can connect to the ZeroMQ socket.
    • The attacker crafts and sends forged ZeroMQ messages.
    • The application processes the forged messages as if they were legitimate, potentially leading to unintended actions or state changes.
  • Likelihood: High (if authentication is not used)
  • Impact: Medium to High (depends on the injected message)
  • Effort: Low
  • Skill Level: Intermediate
  • Detection Difficulty: Medium (if authentication failures are logged)
  • Mitigation: Use the authentication features of ZeroMQ's curve security.

• 4.4 Message Tampering [High-Risk Path]

  • Description: The attacker modifies the content of legitimate ZeroMQ messages to alter the application's behavior or corrupt data.
  • Attack Vector:
    • Similar to MitM, but focuses on modifying existing messages rather than injecting new ones. Requires lack of encryption and authentication.
    • The attacker intercepts a legitimate message.
    • The attacker modifies the message content.
    • The attacker forwards the modified message to the recipient.
  • Likelihood: High (if encryption/authentication is not used)
  • Impact: Medium to High (depends on the tampered message)
  • Effort: Low
  • Skill Level: Intermediate
  • Detection Difficulty: Medium (if authentication failures are logged)
  • Mitigation: Use the authentication and encryption features of ZeroMQ's curve security.

Attack Tree Path: 1. Denial of Service (DoS)

• 1.1 Resource Exhaustion
  • 1.1.2 Memory Exhaustion [High-Risk Path]
    • Description: The attacker sends extremely large messages to the application, consuming excessive memory on the receiving end and potentially causing the application to crash or become unresponsive.
    • Attack Vector:
      • The application does not enforce message size limits using ZMQ_MAXMSGSIZE.
      • The attacker connects to a ZeroMQ socket.
      • The attacker sends one or more very large messages.
      • The receiving application attempts to allocate memory for these messages.
      • If the application runs out of memory, it may crash or become unresponsive.
    • Likelihood: Medium (if message size limits are not enforced)
    • Impact: High (application crash, potential for wider system instability)
    • Effort: Low
    • Skill Level: Novice
    • Detection Difficulty: Medium (memory usage monitoring)
    • Mitigation: Limit maximum message sizes using ZMQ_MAXMSGSIZE.