Allegra uploadSimpleFile Directory Traversal Remote Code Execution Vulnerability

Successful exploitation of CVE-2023-51646 allows an attacker to execute arbitrary code on the Allegra server with LOCAL SERVICE privileges. This could lead to complete system compromise, including data exfiltration, modification, or deletion. The ability to bypass authentication significantly increases the attack surface, as it removes a key security barrier. Given the potential for code execution, the blast radius extends to the entire system and any connected resources accessible by the LOCAL SERVICE account. This vulnerability shares characteristics with other file upload vulnerabilities where insufficient validation allows for path manipulation.

Organizations using Allegra for data visualization and business intelligence, particularly those with sensitive data or critical infrastructure dependencies, are at risk. Shared hosting environments where multiple users share the same Allegra instance are especially vulnerable, as a compromised user account could be used to exploit this vulnerability and impact other users.

• linux / server: Monitor Allegra logs for unusual file upload activity, particularly attempts to upload files with unusual extensions or paths. Use journalctl -f to monitor Allegra's logging output in real-time.

journalctl -f -u allegra # Assuming Allegra runs as a systemd service

• generic web: Use curl to test file upload endpoints and observe the server's response. Check for directory traversal attempts in the response headers or error messages.

curl -F 'file=@malicious_file.php' http://allegra_server/upload.php

1. 2024-11-22Disclosure

   disclosure

1. Reserviert2023-12-20
2. Veröffentlicht2024-11-22
3. Geändert2024-11-25
4. EPSS aktualisiert2026-04-02

The primary mitigation for CVE-2023-51646 is to upgrade Allegra to version 7.5.1 or later, which contains the fix. If upgrading immediately is not possible, consider implementing temporary workarounds. Restrict file upload functionality to trusted users and carefully validate all user-supplied file paths before use. Implement strict access controls to limit the privileges of the LOCAL SERVICE account. Monitor file system activity for suspicious uploads or modifications. While a WAF might offer some protection, it's unlikely to be effective against this type of bypass without specific rules tailored to Allegra’s upload functionality. After upgrading, confirm the fix by attempting a file upload with a malicious path and verifying that it is rejected.