CVE-2018-25412: Delta Sql 1.8.2 Arbitrary File Upload Vulnerability

Delta Sql 1.8.2 is vulnerable to an arbitrary file upload vulnerability (CVE-2018-25412). An unauthenticated attacker can exploit this vulnerability by sending a crafted POST request to the docs_upload.php endpoint. The request must contain multipart form data specifically designed to bypass upload restrictions. Successful exploitation allows the attacker to upload arbitrary files, including PHP files, to the server’s upload directory. This can lead to remote code execution (RCE) as the uploaded files can be accessed and executed by the web server. The impact is significant due to the ease of exploitation and the potential for complete system compromise.

Attack Chain

1. The attacker identifies a Delta Sql 1.8.2 instance.
2. The attacker crafts a malicious PHP file containing arbitrary code to be executed on the server.
3. The attacker crafts a POST request with multipart form data, targeting the docs_upload.php endpoint.
4. The POST request is designed to bypass file type and size restrictions. The filename extension is set to .php
5. The attacker sends the crafted POST request to the vulnerable server.
6. The server saves the malicious PHP file to the upload directory.
7. The attacker accesses the uploaded PHP file via a web browser, triggering its execution on the server.
8. The attacker achieves remote code execution, potentially gaining full control of the server.

Impact

Successful exploitation of CVE-2018-25412 allows an unauthenticated attacker to execute arbitrary code on the affected server. This can lead to complete system compromise, data theft, defacement, or denial-of-service. The lack of authentication makes this vulnerability particularly dangerous. Given the high CVSS score (9.8), immediate action is required to mitigate the risk.

Recommendation

• Apply any available patches or upgrades for Delta Sql to address CVE-2018-25412.
• Implement strict file upload validation on the server to prevent arbitrary file uploads. Block uploads to docs_upload.php via the “Detect CVE-2018-25412 Exploitation — Malicious File Upload” Sigma rule.
• Monitor web server logs for suspicious POST requests to docs_upload.php using the “Detect CVE-2018-25412 Exploitation — Suspicious POST Request” Sigma rule.