CVE-2025-6839
BaseFortify
Publication date: 2025-06-29
Last updated on: 2026-04-29
Assigner: VulDB
Description
Description
CVSS Scores
EPSS Scores
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Meta Information
Affected Vendors & Products
Helpful Resources
Exploitability
| CWE ID | Description |
|---|---|
| CWE-912 | The product contains functionality that is not documented, not part of the specification, and not accessible through an interface or command sequence that is obvious to the product's users or administrators. |
Attack-Flow Graph
AI Powered Q&A
Can you explain this vulnerability to me?
CVE-2025-6839 is a critical backdoor vulnerability in the Conjure Position Department Service Quality Evaluation System up to version 1.0.11. It is embedded in the file public/assets/less/bootstrap-less/mixins/head.php as a hidden PHP webshell. The backdoor uses an XOR cipher with a hardcoded key to encrypt and decrypt payloads sent via POST requests. It stores encrypted payloads in PHP sessions to maintain persistent remote code execution access. Attackers can send specially crafted encrypted commands that are decrypted and executed by the eval() function, allowing arbitrary PHP code execution remotely. The backdoor is stealthily placed in a legitimate-looking directory and uses encrypted communication to evade detection. [1, 3]
How can this vulnerability impact me? :
This vulnerability can lead to full server compromise by enabling attackers to execute arbitrary PHP code remotely. It allows unauthorized access to the system, data exfiltration, privilege escalation, lateral movement within the network, and persistence on the affected server. Sensitive evaluation data and user privacy can be compromised. The stealthy nature of the backdoor complicates detection and remediation, increasing the risk of prolonged unauthorized access and potential damage to business assets. [1, 3, 2]
How can this vulnerability be detected on my network or system? Can you suggest some commands?
Detection can be performed by scanning for the presence of the malicious file `head.php` in the directory `public/assets/less/bootstrap-less/mixins/`. Additionally, monitoring web server logs for suspicious POST requests targeting this file with the parameter `k` carrying base64-encoded, XOR-encrypted payloads is recommended. Commands to detect the file and suspicious activity include: 1. Find the malicious file: `find /var/www/html/public/assets/less/bootstrap-less/mixins/ -name head.php` 2. Search web server logs for suspicious POST requests: `grep 'POST /public/assets/less/bootstrap-less/mixins/head.php' /var/log/apache2/access.log` 3. Look for POST requests containing parameter `k`: `grep 'k=' /var/log/apache2/access.log` 4. Use file integrity monitoring tools to detect unexpected PHP files in static asset directories. 5. Employ web application firewalls (WAF) to detect and block encrypted payloads sent to this endpoint. [1]
What immediate steps should I take to mitigate this vulnerability?
Immediate mitigation steps include: 1. Remove the malicious file `head.php` located in `public/assets/less/bootstrap-less/mixins/`. 2. Conduct thorough scans for similar backdoors in other directories. 3. Review and analyze web server logs for suspicious POST requests targeting this file. 4. Change all administrative passwords and API keys to prevent further unauthorized access. 5. Invalidate all active user sessions to disrupt persistent access. 6. Deploy file integrity monitoring (FIM) and web application firewalls (WAF) to prevent future exploitation. 7. Restrict and validate file uploads strictly. 8. Monitor static asset directories for unusual PHP files. 9. Perform a comprehensive security review and forensic analysis to identify the initial compromise vector and scope of the breach. [1, 3]