CVE-2018-14043
📋 TL;DR
CVE-2018-14043 is an incorrect file access control vulnerability in mstdlib 1.2.0 that allows attackers to access sensitive data by creating files that lack proper permissions. The vulnerability occurs during copy operations when M_fs_perms_can_access attempts to delete existing files. Any application using the vulnerable mstdlib version is affected.
💻 Affected Systems
- mstdlib (M Standard Library for C)
📦 What is this software?
Mstdlib by Monetra
⚠️ Risk & Real-World Impact
Worst Case
Attackers could gain unauthorized access to sensitive files, potentially leading to data theft, privilege escalation, or system compromise.
Likely Case
Local attackers could read or modify files they shouldn't have access to, potentially accessing sensitive configuration or user data.
If Mitigated
With proper file permissions and access controls, the impact is limited to files the attacker already has some access to.
🎯 Exploit Status
Exploitation requires local access to the system and knowledge of the vulnerable copy operation. The attacker needs to create files in specific locations.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Fixed in commit db124b8f607dd0a40a9aef2d4d468fad433522a7
Vendor Advisory: https://github.com/Monetra/mstdlib/commit/db124b8f607dd0a40a9aef2d4d468fad433522a7
Restart Required: Yes
Instructions:
1. Update mstdlib to a version containing commit db124b8f607dd0a40a9aef2d4d468fad433522a7
2. Recompile any applications using mstdlib
3. Restart affected services
🔧 Temporary Workarounds
Restrict file permissions
allApply strict file permissions to sensitive directories and files to limit potential damage
chmod 600 sensitive_file.txt
chmod 700 sensitive_directory/
Disable unnecessary file operations
allIf possible, disable or restrict copy operations in applications using mstdlib
🧯 If You Can't Patch
- Implement strict file system access controls and monitoring
- Isolate applications using mstdlib in containers or virtual machines with limited file system access
🔍 How to Verify
Check if Vulnerable:
Check if your application uses mstdlib version 1.2.0. Review source code or linked libraries for mstdlib usage.Check Version:
Check build configuration or library dependencies for mstdlib versionVerify Fix Applied:
Verify the mstdlib version includes commit db124b8f607dd0a40a9aef2d4d468fad433522a7. Test file copy operations with restricted permissions.📡 Detection & Monitoring
Log Indicators:
- Unexpected file access attempts
- Failed file permission checks during copy operations
- Unauthorized file modifications
Network Indicators:
- None - this is a local file system vulnerability
SIEM Query:
Search for file access events where source process uses mstdlib and accesses files outside expected permissions