CVE-2023-26767
📋 TL;DR
A buffer overflow vulnerability in Liblouis v3.24.0 allows remote attackers to cause denial of service by exploiting the lou_logFile function. This affects systems using Liblouis for braille translation services, particularly those processing untrusted input through affected functions.
💻 Affected Systems
- Liblouis
📦 What is this software?
Liblouis by Liblouis
⚠️ Risk & Real-World Impact
Worst Case
Remote code execution leading to complete system compromise, though buffer overflow typically causes DoS in this context.
Likely Case
Denial of service causing Liblouis service crashes and disruption of braille translation functionality.
If Mitigated
Limited impact with proper input validation and memory protections in place.
🎯 Exploit Status
Exploitation requires crafting specific input to trigger buffer overflow in logging function.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Version 3.25.0 or later
Vendor Advisory: https://github.com/liblouis/liblouis/issues/1292
Restart Required: Yes
Instructions:
1. Check current Liblouis version
2. Update to version 3.25.0 or later
3. Restart services using Liblouis
4. Verify fix with version check
🔧 Temporary Workarounds
Disable vulnerable logging
allDisable or restrict lou_logFile function usage if not required
Configure applications to avoid calling lou_logFile with untrusted input
Input validation
allImplement strict input validation for data passed to Liblouis functions
Add input sanitization before calling Liblouis APIs
🧯 If You Can't Patch
- Implement network segmentation to isolate Liblouis services
- Deploy memory protection mechanisms like ASLR and DEP
🔍 How to Verify
Check if Vulnerable:
Check if Liblouis version is exactly 3.24.0Check Version:
lou_checkVersion or check package manager (e.g., apt list liblouis)Verify Fix Applied:
Confirm Liblouis version is 3.25.0 or later📡 Detection & Monitoring
Log Indicators:
- Liblouis process crashes
- Memory access violation errors
- Abnormal termination of braille services
Network Indicators:
- Unusual traffic patterns to Liblouis services
- Repeated connection attempts to braille translation endpoints
SIEM Query:
Process:Name="liblouis" AND EventID=1000 (Application Crash)