CVE-2023-51640
📋 TL;DR
This vulnerability allows authenticated remote attackers to bypass authentication and execute arbitrary code via a directory traversal flaw in Allegra's extractZippedFile method. It affects Allegra installations where attackers can upload malicious zip files, potentially compromising systems running as LOCAL SERVICE. Users of vulnerable Allegra versions are at risk.
💻 Affected Systems
- Allegra
📦 What is this software?
Allegra by Alltena
⚠️ Risk & Real-World Impact
Worst Case
Remote code execution with LOCAL SERVICE privileges, leading to full system compromise, data theft, or lateral movement within the network.
Likely Case
Unauthorized file access or code execution in the context of the service account, potentially disrupting operations or enabling further attacks.
If Mitigated
Limited impact if proper input validation and access controls are enforced, though authentication bypass may still pose risks.
🎯 Exploit Status
Exploitation requires authentication bypass and crafting malicious zip files; details are disclosed in ZDI advisory ZDI-24-107.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 7.5.1
Vendor Advisory: https://www.trackplus.com/en/service/release-notes-reader/7-5-1-release-notes-2.html
Restart Required: Yes
Instructions:
1. Download Allegra version 7.5.1 from the vendor. 2. Backup current installation and data. 3. Apply the update following vendor instructions. 4. Restart the Allegra service to activate the patch.
🔧 Temporary Workarounds
Restrict File Uploads
allBlock or monitor uploads of zip files to Allegra to prevent exploitation.
Use firewall rules or application controls to deny .zip uploads to Allegra endpoints.
Enforce Strong Authentication
allImplement multi-factor authentication to reduce risk of authentication bypass.
Configure MFA for Allegra user accounts via vendor settings or external identity provider.
🧯 If You Can't Patch
- Isolate Allegra systems from the internet and restrict internal access to trusted users only.
- Monitor logs for unusual file operations or authentication attempts and implement network segmentation.
🔍 How to Verify
Check if Vulnerable:
Check Allegra version; if below 7.5.1, it is likely vulnerable. Review logs for suspicious extractZippedFile activity.Check Version:
Check Allegra admin interface or configuration files for version number; on Linux, run 'allegra --version' if available.Verify Fix Applied:
Confirm Allegra version is 7.5.1 or higher via the version check command and test file uploads for proper path validation.📡 Detection & Monitoring
Log Indicators:
- Failed authentication attempts followed by file extraction events
- Log entries referencing extractZippedFile with unusual paths
Network Indicators:
- Unusual HTTP POST requests to Allegra endpoints with zip file uploads
- Traffic spikes to Allegra service ports
SIEM Query:
source="allegra_logs" AND (event="file_upload" OR event="authentication_failure") | stats count by src_ip