CVE-2023-31483
📋 TL;DR
This vulnerability allows attackers to perform directory traversal attacks via crafted tar archives in Cauldron cbang's tar extraction functionality. Attackers can create or overwrite files outside the intended extraction directory, potentially leading to arbitrary file writes. This affects systems using cbang versions before bastet-v8.1.17.
💻 Affected Systems
- Cauldron cbang
📦 What is this software?
Cbang by Cauldrondevelopment
⚠️ Risk & Real-World Impact
Worst Case
Complete system compromise via arbitrary file writes leading to remote code execution, privilege escalation, or data destruction.
Likely Case
Unauthorized file creation/modification outside extraction directory, potentially leading to data corruption, privilege escalation, or denial of service.
If Mitigated
Limited impact with proper file permissions and sandboxing, potentially only affecting non-critical files.
🎯 Exploit Status
Exploitation requires ability to provide crafted tar archives to vulnerable extraction functionality.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: bastet-v8.1.17 and later
Vendor Advisory: https://github.com/CauldronDevelopmentLLC/cbang/compare/bastet-v8.1.16...bastet-v8.1.17
Restart Required: No
Instructions:
1. Update cbang to version bastet-v8.1.17 or later. 2. Rebuild any applications using cbang. 3. Replace existing installations with patched version.
🔧 Temporary Workarounds
Validate tar archive paths
allImplement path validation before extraction to prevent directory traversal
Implement custom validation: if (path.contains("..") || path.startsWith("/")) { reject_archive(); }
Use extraction sandbox
linuxExtract archives in isolated directories with restricted permissions
mkdir -p /tmp/sandbox_$(date +%s) && chmod 700 /tmp/sandbox_*
cd /tmp/sandbox_* && tar -xf archive.tar
🧯 If You Can't Patch
- Disable tar extraction functionality in cbang if not required
- Implement strict input validation and sanitization for all tar archive processing
🔍 How to Verify
Check if Vulnerable:
Check cbang version: if version < bastet-v8.1.17, system is vulnerableCheck Version:
Check build configuration or application dependencies for cbang versionVerify Fix Applied:
Confirm cbang version is bastet-v8.1.17 or later and test tar extraction with crafted archives📡 Detection & Monitoring
Log Indicators:
- Unexpected file creation/modification outside extraction directories
- Failed tar extraction attempts with suspicious paths
Network Indicators:
- Large or unusual tar archive uploads to applications
SIEM Query:
file_create OR file_modify WHERE path CONTAINS ".." AND process_name="cbang"