CVE-2015-4042
📋 TL;DR
This CVE describes an integer overflow vulnerability in GNU Coreutils' sort command that can be triggered via long strings. Attackers could cause denial of service (application crash) or potentially execute arbitrary code. Systems using vulnerable versions of GNU Coreutils (through 8.23) are affected.
💻 Affected Systems
- GNU Coreutils
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Remote code execution leading to complete system compromise if the overflow can be leveraged for memory corruption attacks.
Likely Case
Application crash (denial of service) when processing malicious input through the sort command.
If Mitigated
Limited to denial of service if exploit attempts are blocked or systems are patched.
🎯 Exploit Status
Proof of concept exists in public advisories. Exploitation requires feeding long strings to the sort command.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 8.24 and later
Vendor Advisory: http://openwall.com/lists/oss-security/2015/05/15/1
Restart Required: No
Instructions:
1. Update GNU Coreutils to version 8.24 or later. 2. On Debian/Ubuntu: apt-get update && apt-get install coreutils. 3. On RHEL/CentOS: yum update coreutils. 4. On other systems, compile from source with the fix applied.
🔧 Temporary Workarounds
Input validation wrapper
linuxCreate a wrapper script that validates input length before passing to sort
#!/bin/bash
MAX_LEN=1000000
if [ ${#1} -gt $MAX_LEN ]; then
echo "Input too long"
exit 1
fi
sort "$@"
🧯 If You Can't Patch
- Restrict sort command usage to trusted users only via sudoers or permissions
- Monitor for abnormal sort command usage patterns and long input strings
🔍 How to Verify
Check if Vulnerable:
Run: sort --version | head -1 | grep -q '8.23\|8.22\|8.21\|8.20\|8.19\|8.18\|8.17\|8.16\|8.15\|8.14\|8.13\|8.12\|8.11\|8.10\|8.9\|8.8\|8.7\|8.6\|8.5\|8.4\|8.3\|8.2\|8.1\|8.0' && echo "VULNERABLE" || echo "NOT VULNERABLE"Check Version:
sort --version | head -1Verify Fix Applied:
Run: sort --version | head -1 | grep -q '8.24\|8.25\|8.26\|8.27\|8.28\|8.29\|8.30\|8.31\|8.32' && echo "PATCHED" || echo "NOT PATCHED"📡 Detection & Monitoring
Log Indicators:
- Segmentation fault or crash logs from sort process
- Abnormally long command line arguments to sort
Network Indicators:
- Unusual network traffic to systems running sort on network input
SIEM Query:
process.name="sort" AND (command_line.length>1000000 OR exit_code=139)