attack-tree.md

Attack Tree Analysis for facebook/zstd

Objective: Compromise Application via Zstd Exploitation (Focus on High-Risk Paths)

Attack Tree Visualization

High-Risk Paths for Compromising Application via Zstd ├───[AND] [HIGH RISK PATH] Exploit Zstd Library Vulnerabilities │ ├───[OR] [HIGH RISK PATH] Memory Corruption Vulnerabilities │ │ ├───[AND] [HIGH RISK PATH] Buffer Overflow in Decompression [CRITICAL NODE] │ │ │ ├───[OR] Crafted Malicious Compressed Data │ │ │ └─── Application Misuse of Zstd API [CRITICAL NODE] │ │ ├───[OR] [HIGH RISK PATH] Heap Overflow in Decompression [CRITICAL NODE] │ │ ├───[OR] [HIGH RISK PATH] Integer Overflow/Underflow [CRITICAL NODE] │ └───[OR] [HIGH RISK PATH] Denial of Service (DoS) via Zstd [CRITICAL NODE] │ ├───[AND] [HIGH RISK PATH] Decompression Bomb (Zip Bomb Analogue) [CRITICAL NODE] ├───[AND] [HIGH RISK PATH] Exploit Misconfiguration/Misuse of Zstd in Application [CRITICAL NODE] │ ├───[OR] [HIGH RISK PATH] Using Outdated/Vulnerable Zstd Version [CRITICAL NODE] │ ├───[OR] [HIGH RISK PATH] Insecure Integration with Application Logic [CRITICAL NODE]

Attack Tree Path: Exploit Zstd Library Vulnerabilities

• Description: This path focuses on exploiting inherent vulnerabilities within the zstd library itself. If successful, these attacks can bypass application-level defenses and directly compromise the system.

  • Mitigation Strategies:
    • Keep Zstd Updated: Regularly update to the latest stable version of zstd to patch known vulnerabilities.
    • Fuzzing and Testing: Thoroughly fuzz and test the application's Zstd integration to uncover potential vulnerabilities before attackers do.

Attack Tree Path: Memory Corruption Vulnerabilities

• Description: Memory corruption vulnerabilities are a class of bugs that can lead to serious security issues, including code execution and denial of service. In the context of zstd, these typically occur during decompression due to improper memory handling.

  • Mitigation Strategies:

    • Memory Safety Tools: Use memory safety tools (e.g., AddressSanitizer, MemorySanitizer, Valgrind) during development and testing to detect memory errors early.
    • Robust Buffer Handling: Ensure correct buffer size allocation and bounds checking when using Zstd API, especially for decompression.

  • 2.1. [HIGH RISK PATH] Buffer Overflow in Decompression [CRITICAL NODE]

    • Attack Vector:
      • Crafted Malicious Compressed Data: Attacker provides specially crafted compressed data designed to cause zstd decompression to write beyond the allocated buffer. This can overwrite adjacent memory regions.
      • Application Misuse of Zstd API [CRITICAL NODE]: The application incorrectly uses the zstd API, such as allocating an insufficient buffer for decompression or passing incorrect parameters, leading to a buffer overflow.
    • Impact: Code execution, denial of service, information disclosure.
    • Mitigation:
      • Input Validation (Limited): While difficult for compressed data itself, validate the source and context of compressed data.
      • Safe Buffer Allocation: Allocate buffers large enough to accommodate the maximum expected decompressed size.
      • API Usage Review: Carefully review and test the application's usage of the zstd API to ensure correct buffer handling.

  • 2.2. [HIGH RISK PATH] Heap Overflow in Decompression [CRITICAL NODE]

    • Attack Vector:
      • Crafted Malicious Compressed Data: Attacker provides compressed data designed to trigger a heap overflow during decompression, corrupting heap memory.
      • Zstd Library Bug: An undiscovered bug within the zstd library itself could lead to heap overflows.
    • Impact: Code execution, denial of service, information disclosure.
    • Mitigation:
      • Memory Safety Tools: Crucial for detecting heap overflows during testing.
      • Keep Zstd Updated: Benefit from security fixes in newer versions of zstd.

  • 2.3. [HIGH RISK PATH] Integer Overflow/Underflow [CRITICAL NODE]

    • Attack Vector:
      • Crafted Malicious Compressed Data: Attacker provides compressed data with headers crafted to cause integer overflows or underflows during size calculations within zstd. This can lead to incorrect buffer allocations and subsequent memory corruption.
      • Zstd Library Bug: An undiscovered bug in zstd could lead to integer overflow/underflow vulnerabilities.
    • Impact: Memory corruption, code execution, denial of service.
    • Mitigation:
      • Code Review: Review code that handles size calculations related to zstd decompression.
      • Fuzzing: Fuzzing can help identify inputs that trigger integer overflows.
      • Keep Zstd Updated: Benefit from security fixes.

Attack Tree Path: Denial of Service (DoS) via Zstd

• Description: DoS attacks aim to make the application unavailable to legitimate users. zstd decompression, being a potentially resource-intensive operation, can be a target for DoS attacks.

  • Mitigation Strategies:

    • Resource Limits: Implement limits on resources consumed by decompression operations (e.g., memory, CPU time).
    • Input Validation (Size Limits): Implement limits on the size of compressed data accepted for decompression.

  • 3.1. [HIGH RISK PATH] Decompression Bomb (Zip Bomb Analogue) [CRITICAL NODE]

    • Attack Vector:
      • Supply highly compressible data: Attacker provides compressed data that has an extremely high compression ratio. When decompressed, it expands to an enormous size, potentially exhausting server resources (memory, CPU, disk I/O).
    • Impact: Severe denial of service, service disruption, system crash.
    • Mitigation:
      • Decompressed Size Limits [CRITICAL MITIGATION]: Implement strict limits on the maximum decompressed size allowed. If decompression exceeds this limit, immediately abort the operation and handle the error. This is the most effective defense against decompression bombs.
      • Resource Monitoring: Monitor server resources during decompression and implement safeguards to prevent resource exhaustion.

Attack Tree Path: Exploit Misconfiguration/Misuse of Zstd in Application

• Description: This path focuses on vulnerabilities arising from how the application integrates and uses the zstd library, rather than bugs within zstd itself. Misconfigurations and misuse are common sources of security vulnerabilities.

  • Mitigation Strategies:

    • Secure Coding Practices: Follow secure coding practices when integrating zstd.
    • Regular Security Audits: Conduct security audits to identify misconfigurations and misuse issues.

  • 4.1. [HIGH RISK PATH] Using Outdated/Vulnerable Zstd Version [CRITICAL NODE]

    • Attack Vector:
      • Outdated Dependency: The application uses an older version of zstd that contains known security vulnerabilities (CVEs). Attackers can exploit these publicly known vulnerabilities.
    • Impact: Depends on the specific vulnerability, but can range from denial of service to code execution and data breaches.
    • Mitigation:
      • Dependency Management [CRITICAL MITIGATION]: Implement a robust dependency management system to track and update dependencies, including zstd.
      • Regular Updates [CRITICAL MITIGATION]: Establish a process for regularly updating dependencies to the latest stable versions, prioritizing security updates.
      • Vulnerability Scanning: Use vulnerability scanning tools to identify known vulnerabilities in dependencies.

  • 4.2. [HIGH RISK PATH] Insecure Integration with Application Logic [CRITICAL NODE]

    • Attack Vector:
      • Unvalidated input passed to Zstd decompression: The application directly decompresses untrusted or unvalidated input without proper checks, potentially exposing it to malicious compressed data attacks.
      • Incorrect handling of decompressed data: The application incorrectly handles the decompressed data, leading to further vulnerabilities. For example, if decompressed data is used in command execution without proper sanitization, it can lead to command injection.
    • Impact: Injection attacks (command injection, SQL injection, etc.), data breaches, code execution (depending on how decompressed data is used).
    • Mitigation:
      • Input Validation and Sanitization [CRITICAL MITIGATION]: Always sanitize and validate decompressed data before using it in security-sensitive operations.
      • Principle of Least Privilege: Run the application with the minimum necessary privileges to limit the impact of a successful exploit.
      • Secure Design Review: Conduct security design reviews of the application's Zstd integration to identify potential vulnerabilities in how Zstd is used within the application's logic.