CVE-2023-40359
📋 TL;DR
This CVE describes a memory corruption vulnerability in xterm's ReGIS reporting feature that can lead to arbitrary code execution. Only xterm installations compiled with experimental ReGIS support are affected. Attackers could exploit this by sending specially crafted terminal sequences to vulnerable xterm instances.
💻 Affected Systems
- xterm
📦 What is this software?
Xterm by Invisible Island
⚠️ Risk & Real-World Impact
Worst Case
Remote code execution with root privileges leading to complete system compromise
Likely Case
Local privilege escalation or denial of service affecting xterm sessions
If Mitigated
Limited impact due to the experimental nature of the feature and compile-time requirement
🎯 Exploit Status
Requires sending malicious terminal sequences to vulnerable xterm instance
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: xterm 380
Vendor Advisory: https://invisible-island.net/xterm/xterm.log.html#xterm_380
Restart Required: Yes
Instructions:
1. Download xterm 380 or later from https://invisible-island.net/xterm 2. Compile and install according to distribution instructions 3. Restart all xterm sessions
🔧 Temporary Workarounds
Disable ReGIS support
linuxRecompile xterm without experimental ReGIS support
./configure --disable-regis
make
sudo make install
🧯 If You Can't Patch
- Restrict access to xterm sessions to trusted users only
- Monitor for unusual terminal sequence patterns in logs
🔍 How to Verify
Check if Vulnerable:
Check xterm version with 'xterm -version' and verify if compiled with ReGIS supportCheck Version:
xterm -version 2>&1 | head -1Verify Fix Applied:
Confirm xterm version is 380 or later with 'xterm -version'📡 Detection & Monitoring
Log Indicators:
- Unusual terminal escape sequences in system logs
- xterm crash reports
Network Indicators:
- Malformed terminal sequences in SSH/Telnet sessions
SIEM Query:
process:xterm AND (event:crash OR event:segfault)