CVE-2024-21502
📋 TL;DR
CVE-2024-21502 is a use of uninitialized variable vulnerability in fastecdsa's curvemath_mul function that allows attackers to control stack memory. This can lead to arbitrary free/realloc operations, null pointer dereferences, and heap corruption, potentially enabling denial of service or code execution. Users of fastecdsa versions before 2.3.2 are affected.
💻 Affected Systems
- fastecdsa
📦 What is this software?
Fastecdsa by Antonkueltz
⚠️ Risk & Real-World Impact
Worst Case
Remote code execution through heap exploitation leading to complete system compromise.
Likely Case
Denial of service through application crashes or memory corruption.
If Mitigated
Limited impact if proper memory protections and exploit mitigations are enabled.
🎯 Exploit Status
Proof of concept available in GitHub gist; exploitation requires triggering the vulnerable curvemath_mul function.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 2.3.2
Vendor Advisory: https://github.com/AntonKueltz/fastecdsa/commit/57fc5689c95d649dab7ef60cc99ac64589f01e36
Restart Required: No
Instructions:
1. Update fastecdsa package using pip: pip install --upgrade fastecdsa==2.3.2
2. Verify installation with: pip show fastecdsa
3. Restart any services using fastecdsa.
🔧 Temporary Workarounds
Disable vulnerable functionality
allAvoid using curvemath_mul function or disable affected cryptographic operations.
🧯 If You Can't Patch
- Implement strict input validation and sanitization for all inputs to fastecdsa functions.
- Deploy memory protection mechanisms like ASLR and stack canaries to reduce exploit success.
🔍 How to Verify
Check if Vulnerable:
Check installed fastecdsa version: pip show fastecdsa | grep VersionCheck Version:
pip show fastecdsa | grep VersionVerify Fix Applied:
Confirm version is 2.3.2 or higher: pip show fastecdsa | grep Version📡 Detection & Monitoring
Log Indicators:
- Application crashes, segmentation faults, abnormal memory usage patterns
Network Indicators:
- Unusual requests to services using fastecdsa, especially with crafted cryptographic inputs
SIEM Query:
Process monitoring for fastecdsa-related crashes or memory corruption events.🔗 References
- https://gist.github.com/keltecc/49da037072276f21b005a8337c15db26
- https://github.com/AntonKueltz/fastecdsa/blob/v2.3.1/src/curveMath.c%23L210
- https://github.com/AntonKueltz/fastecdsa/commit/57fc5689c95d649dab7ef60cc99ac64589f01e36
- https://security.snyk.io/vuln/SNYK-PYTHON-FASTECDSA-6262045
- https://gist.github.com/keltecc/49da037072276f21b005a8337c15db26
- https://github.com/AntonKueltz/fastecdsa/blob/v2.3.1/src/curveMath.c%23L210
- https://github.com/AntonKueltz/fastecdsa/commit/57fc5689c95d649dab7ef60cc99ac64589f01e36
- https://security.snyk.io/vuln/SNYK-PYTHON-FASTECDSA-6262045
