CVE-2024-9143 Overview
CVE-2024-9143 is an out-of-bounds memory access vulnerability affecting OpenSSL's low-level GF(2^m) elliptic curve APIs. When untrusted explicit values for the field polynomial are provided to these APIs, the vulnerability can lead to out-of-bounds memory reads or writes, potentially causing application crashes or enabling remote code execution in certain scenarios.
The vulnerability impacts applications that work with "exotic" explicit binary (GF(2^m)) curve parameters that make it possible to represent invalid field polynomials with a zero constant term. While the likelihood of exploitation is considered low due to limited real-world usage of these specific API patterns, the potential impact of memory corruption makes this a noteworthy security concern for affected deployments.
Critical Impact
Out-of-bounds memory writes can lead to application crashes or potentially remote code execution in applications using exotic GF(2^m) curve parameters with untrusted input values.
Affected Products
- OpenSSL versions prior to security patches released October 2024
- Applications using EC_GROUP_new_curve_GF2m(), EC_GROUP_new_from_params(), and related BN_GF2m_*() functions with untrusted explicit curve parameters
- Note: OpenSSL FIPS modules in versions 3.3, 3.2, 3.1, and 3.0 are NOT affected
Discovery Timeline
- 2024-10-16 - CVE-2024-9143 published to NVD
- 2024-10-16 - OpenSSL releases security patches and advisory
- 2025-11-03 - Last updated in NVD database
Technical Details for CVE-2024-9143
Vulnerability Analysis
This vulnerability resides in OpenSSL's implementation of elliptic curve cryptography, specifically within the binary field (GF(2^m)) polynomial handling code. The affected functions include EC_GROUP_new_curve_GF2m(), EC_GROUP_new_from_params(), and various supporting BN_GF2m_*() functions in the crypto/bn/bn_gf2m.c file.
When these APIs receive untrusted explicit values for field polynomials, particularly those that represent invalid polynomials with a zero constant term, the code can perform out-of-bounds array accesses. This occurs during the polynomial-to-array conversion process in BN_GF2m_poly2arr() and related functions.
Importantly, standard protocols using Elliptic Curve Cryptography typically either support only "named curves" or use X9.62 encoding for explicit curve parameters, which cannot represent the problematic input values. This significantly limits the practical attack surface. The X9.62 encoding used in X.509 certificates, for example, cannot trigger this vulnerability.
Root Cause
The root cause is insufficient input validation in the BN_GF2m_poly2arr() function when processing explicit field polynomial values. The function fails to properly validate that the polynomial has a valid constant term before performing array operations, allowing malformed input to cause memory access outside allocated buffer boundaries.
Attack Vector
The attack requires an application that:
- Uses the affected low-level GF(2^m) elliptic curve APIs
- Accepts explicit curve parameters from untrusted sources
- Uses a non-standard encoding that can represent invalid field polynomials with zero constant terms
An attacker would need to supply a specially crafted field polynomial value to trigger the out-of-bounds access. The network-based attack vector indicates exploitation can occur remotely if the vulnerable application processes attacker-controlled cryptographic parameters.
// Security patch from OpenSSL commit - Harden BN_GF2m_poly2arr against misuse
// Source: https://github.com/openssl/openssl/commit/72ae83ad214d2eef262461365a1975707f862712
#include "bn_local.h"
#ifndef OPENSSL_NO_EC2M
# include <openssl/ec.h>
/*
* Maximum number of iterations before BN_GF2m_mod_solve_quad_arr should
The patch adds additional header inclusion and validation to harden the BN_GF2m_poly2arr() function against misuse with malformed polynomial inputs.
Detection Methods for CVE-2024-9143
Indicators of Compromise
- Application crashes or segmentation faults in processes using OpenSSL cryptographic operations
- Unexpected termination of services that process elliptic curve parameters
- Memory corruption signatures in application crash dumps referencing bn_gf2m.c or related EC functions
- Anomalous cryptographic operation failures in logs
Detection Strategies
- Monitor for process crashes in applications linked against vulnerable OpenSSL versions
- Implement runtime memory protection tools (ASAN, Valgrind) in development/testing environments to detect out-of-bounds access
- Review application code for usage of affected APIs: EC_GROUP_new_curve_GF2m(), EC_GROUP_new_from_params(), and BN_GF2m_*() functions
- Use software composition analysis (SCA) tools to identify vulnerable OpenSSL versions in your environment
Monitoring Recommendations
- Enable core dump analysis for cryptographic services to identify potential exploitation attempts
- Monitor system logs for OpenSSL-related error messages involving elliptic curve operations
- Implement application-level monitoring for unexpected cryptographic operation failures
- Deploy SentinelOne endpoint protection to detect memory corruption exploitation attempts
How to Mitigate CVE-2024-9143
Immediate Actions Required
- Update OpenSSL to the patched version immediately on all affected systems
- Audit applications for usage of the affected GF(2^m) elliptic curve APIs with untrusted input
- Restrict applications to use only named curves rather than explicit curve parameters where possible
- Apply vendor-specific patches from downstream distributions (Debian, NetApp, etc.)
Patch Information
OpenSSL has released security patches addressing this vulnerability. The fixes harden the BN_GF2m_poly2arr() function against misuse by adding proper input validation. Multiple commits have been published:
For extended release branches, see the OpenSSL Extended Releases Commits. Additional information is available in the OpenSSL Security Advisory.
Distribution-specific patches are available:
Workarounds
- Configure applications to reject explicit curve parameters and use only named/well-known curves
- Implement input validation at the application layer to filter malformed elliptic curve parameters before they reach OpenSSL APIs
- Consider disabling EC2M support entirely if binary field elliptic curves are not required (OPENSSL_NO_EC2M)
- Isolate applications using legacy explicit curve parameters in sandboxed environments
# Check OpenSSL version and verify patch status
openssl version -a
# Verify OpenSSL is compiled without EC2M if not needed
openssl ecparam -list_curves | grep -i "binary"
# Update OpenSSL on Debian/Ubuntu systems
sudo apt update && sudo apt upgrade openssl libssl-dev
# Update OpenSSL on RHEL/CentOS systems
sudo yum update openssl openssl-devel
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
