CVE-2025-13651

Executive Summary

CVE-2025-13651 is an information disclosure vulnerability in Microcom ZeusWeb version 6.1.31. The flaw allows an unauthenticated attacker to perform web application fingerprinting, exposing sensitive system information such as server banners, internal paths, and software versions. This exposure can aid in reconnaissance for further attacks. No patch or public exploit is currently available.

Supply Chain & Package Security

This vulnerability is not related to an NPM, PyPI, Go, or Ruby package. It affects a proprietary web application (ZeusWeb) from Microcom. No supply chain implications are identified.

CVSS Breakdown & Threat Level

• CVSS Score: 0.0 (No official vector assigned)
• Severity: Low (based on information disclosure nature)
• Attack Vector: Network
• Attack Complexity: Low
• Privileges Required: None
• User Interaction: None
• Scope: Unchanged
• Confidentiality Impact: Low
• Integrity Impact: None
• Availability Impact: None

Deep Dive & Mechanics

The vulnerability resides in the ZeusWeb application's response handling. When an unauthenticated request is made to the web server, the application leaks sensitive system information in HTTP headers, error pages, or directory listings. This includes:

• Server software version (e.g., Server: ZeusWeb/6.1.31)
• Internal IP addresses or hostnames
• File system paths (e.g., /var/www/zeusweb/)
• Application framework details

The root cause is improper sanitization of error messages and default server banners. An attacker can use tools like curl or nmap to extract this data.

Vulnerable vs. Patched Code

No patched version exists. The vulnerable code is in the application's response headers and error handling routines.

Vulnerable behavior (example HTTP response):

HTTP/1.1 200 OK
Server: ZeusWeb/6.1.31
X-Powered-By: ZeusWeb/6.1.31
Content-Type: text/html

<!DOCTYPE html>
<html>
<head><title>ZeusWeb - Error</title></head>
<body>
<h1>Internal Server Error</h1>
<p>File not found: /var/www/zeusweb/app/controllers/error.php</p>
</body>
</html>

Patched behavior (hypothetical):

HTTP/1.1 200 OK
Server: Apache
Content-Type: text/html

<!DOCTYPE html>
<html>
<head><title>Error</title></head>
<body>
<h1>Error</h1>
<p>An error occurred.</p>
</body>
</html>

Exploitation & Lab Setup

Red Team

1. Reconnaissance: Use curl -I http://target:port/ to capture server headers.
2. Fingerprinting: Send malformed requests to trigger error messages:

   curl http://target:port/nonexistent
   

3. Data Extraction: Parse responses for version strings, paths, and internal IPs.

Lab Setup:

• Install ZeusWeb 6.1.31 on a Linux VM.
• Expose on port 80.
• Use Kali Linux as attacker.

Blue Team

1. Detection: Monitor for requests to non-existent resources and unusual User-Agent strings.
2. Honeypot: Deploy a fake ZeusWeb instance to capture attacker behavior.
3. Logging: Enable detailed access logs and alert on Server: ZeusWeb headers.

Indicators of Compromise (IOCs)

• HTTP Response Header: Server: ZeusWeb/6.1.31
• Error Page Content: ZeusWeb in title or body
• URL Patterns: /zeusweb/, /app/controllers/
• Internal Paths: /var/www/zeusweb/

Detection Engineering

YARA Rule

rule CVE_2025_13651_ZeusWeb_Fingerprinting {
    meta:
        description = "Detects ZeusWeb fingerprinting attempts via HTTP responses"
        author = "Valters IT"
        date = "2025-04-10"
        cve = "CVE-2025-13651"
    strings:
        $s1 = "Server: ZeusWeb/" ascii wide nocase
        $s2 = "ZeusWeb" ascii wide nocase
        $s3 = "/var/www/zeusweb/" ascii wide nocase
    condition:
        any of them
}

Sigma Rule

title: ZeusWeb Fingerprinting Detection
id: 8a9b7c6d-5e4f-3a2b-1c0d-9e8f7a6b5c4d
status: experimental
description: Detects HTTP responses containing ZeusWeb server header or error paths
author: Valters IT
date: 2025-04-10
logsource:
    category: webserver
    product: apache
detection:
    selection:
        response_header|contains: "Server: ZeusWeb/"
    condition: selection
falsepositives:
    - Legitimate ZeusWeb servers
level: low

Suricata Rule

alert http any any -> any any (msg:"CVE-2025-13651 ZeusWeb Fingerprinting"; flow:to_client; content:"Server: ZeusWeb/"; http_server; classtype:attempted-recon; sid:1000001; rev:1;)

Remediation & Mitigation

• Immediate: Disable server banners in ZeusWeb configuration (if possible).
• Workaround: Place a reverse proxy (e.g., Nginx) in front of ZeusWeb to strip sensitive headers.
• Long-term: Contact Microcom for a patch or migrate to an alternative solution.
• Monitoring: Implement the detection rules above to identify scanning attempts.

Valters IT
DevSecOps & Cyber Threat Intelligence