CVE-2021-43618
📋 TL;DR
CVE-2021-43618 is an integer overflow vulnerability in GNU Multiple Precision Arithmetic Library (GMP) that leads to buffer overflow when processing crafted input. This causes segmentation faults on 32-bit platforms, potentially allowing denial of service or arbitrary code execution. Any application using GMP for arbitrary-precision arithmetic on 32-bit systems is affected.
💻 Affected Systems
- GNU Multiple Precision Arithmetic Library (GMP)
📦 What is this software?
Gmp by Gmplib
⚠️ Risk & Real-World Impact
Worst Case
Remote code execution leading to complete system compromise if exploit chains with other vulnerabilities
Likely Case
Denial of service through segmentation faults and application crashes
If Mitigated
Limited to denial of service with proper memory protections and exploit mitigations
🎯 Exploit Status
Exploit requires crafting specific input to trigger integer overflow; public PoC available in references
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: GMP 6.2.2 and later
Vendor Advisory: https://gmplib.org/list-archives/gmp-bugs/2021-September/005077.html
Restart Required: Yes
Instructions:
1. Download GMP 6.2.2 or later from gmplib.org
2. Compile and install: ./configure && make && make install
3. Recompile any applications using GMP with updated library
4. Restart affected services
🔧 Temporary Workarounds
Input validation
allImplement strict input validation for GMP function calls
No specific commands - implement in application code
Memory protection
linuxEnable ASLR and other memory protection mechanisms
echo 2 > /proc/sys/kernel/randomize_va_space
🧯 If You Can't Patch
- Migrate to 64-bit systems where possible
- Implement network segmentation to limit exposure of vulnerable systems
🔍 How to Verify
Check if Vulnerable:
Check GMP version: gmp-config --version or ldd on binary to check linked library versionCheck Version:
gmp-config --version || grep -r "libgmp" /usr/lib*/libgmp*Verify Fix Applied:
Verify GMP version is 6.2.2 or higher and recompile applications📡 Detection & Monitoring
Log Indicators:
- Segmentation fault errors in application logs
- Core dumps from GMP-linked applications
Network Indicators:
- Unusual input patterns to applications using GMP
SIEM Query:
source="application.log" AND "segmentation fault" AND "GMP"🔗 References
- http://seclists.org/fulldisclosure/2022/Oct/8
- http://www.openwall.com/lists/oss-security/2022/10/13/3
- https://bugs.debian.org/994405
- https://gmplib.org/list-archives/gmp-bugs/2021-September/005077.html
- https://gmplib.org/repo/gmp-6.2/rev/561a9c25298e
- https://lists.debian.org/debian-lts-announce/2021/12/msg00001.html
- https://security.gentoo.org/glsa/202309-13
- https://security.netapp.com/advisory/ntap-20221111-0001/
- http://seclists.org/fulldisclosure/2022/Oct/8
- http://www.openwall.com/lists/oss-security/2022/10/13/3
- https://bugs.debian.org/994405
- https://gmplib.org/list-archives/gmp-bugs/2021-September/005077.html
- https://gmplib.org/repo/gmp-6.2/rev/561a9c25298e
- https://lists.debian.org/debian-lts-announce/2021/12/msg00001.html
- https://security.gentoo.org/glsa/202309-13
- https://security.netapp.com/advisory/ntap-20221111-0001/
