CVE-2023-25139
📋 TL;DR
CVE-2023-25139 is a buffer overflow vulnerability in glibc's sprintf function that occurs when formatting numbers with thousands separators and padding. This allows attackers to write beyond allocated buffer boundaries, potentially leading to memory corruption, crashes, or arbitrary code execution. Any system using glibc 2.37 with applications that use sprintf for formatted numeric output is affected.
💻 Affected Systems
- GNU C Library (glibc)
📦 What is this software?
Glibc by Gnu
The GNU C Library (glibc) is the core C library for Linux systems, providing essential system calls and basic functions for all C programs. It is a fundamental component that nearly every Linux application depends on.
Learn more about Glibc →⚠️ Risk & Real-World Impact
Worst Case
Remote code execution leading to complete system compromise, data theft, or ransomware deployment.
Likely Case
Application crashes, denial of service, or limited memory corruption affecting specific processes.
If Mitigated
Contained crashes of individual applications without system-wide impact if proper memory protections are enabled.
🎯 Exploit Status
Exploitation requires specific application code patterns but is feasible with public technical details available.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: glibc 2.38 or patched 2.37 versions from distributions
Vendor Advisory: https://sourceware.org/bugzilla/show_bug.cgi?id=30068
Restart Required: Yes
Instructions:
1. Update glibc package using your distribution's package manager. 2. For Red Hat/CentOS: yum update glibc. 3. For Debian/Ubuntu: apt update && apt upgrade libc6. 4. Restart affected services or reboot system.
🔧 Temporary Workarounds
Disable thousands separators
linuxConfigure applications to avoid using thousands separators in sprintf formatting
export LC_NUMERIC=C
export LC_ALL=C
Use alternative formatting functions
allReplace sprintf with snprintf or other safer alternatives in application code
🧯 If You Can't Patch
- Implement strict input validation for numeric formatting in applications
- Enable ASLR and other memory protection mechanisms to reduce exploit impact
🔍 How to Verify
Check if Vulnerable:
Check glibc version: ldd --version | grep glibc. If version is exactly 2.37, system is vulnerable.Check Version:
ldd --version | grep glibcVerify Fix Applied:
Verify glibc version is not 2.37: ldd --version | grep glibc. Should show 2.38 or patched 2.37 version.📡 Detection & Monitoring
Log Indicators:
- Application crashes with segmentation faults
- Memory corruption errors in system logs
- Unexpected process terminations
Network Indicators:
- Unusual network traffic to services using glibc
- Exploit attempt patterns in web server logs
SIEM Query:
source="*syslog*" AND ("segmentation fault" OR "SIGSEGV") AND process="*" AND glibc_version="2.37"🔗 References
- http://www.openwall.com/lists/oss-security/2023/02/10/1
- https://security.netapp.com/advisory/ntap-20230302-0010/
- https://sourceware.org/bugzilla/show_bug.cgi?id=30068
- http://www.openwall.com/lists/oss-security/2023/02/10/1
- https://security.netapp.com/advisory/ntap-20230302-0010/
- https://sourceware.org/bugzilla/show_bug.cgi?id=30068
