CVE-2013-10051

Comprehensive Technical Analysis of CVE-2013-10051

1. Vulnerability Assessment and Severity Evaluation

CVE ID: CVE-2013-10051 CVSS Score: 9.8

The vulnerability in question is a remote PHP code execution flaw in InstantCMS version 1.6 and earlier. The high CVSS score of 9.8 indicates a critical severity level, reflecting the potential for significant impact if exploited. The vulnerability arises from the unsafe use of the eval() function within the search view handler, which allows user-supplied input to be executed without proper sanitation. This can lead to arbitrary PHP code execution within the context of the web server.

2. Potential Attack Vectors and Exploitation Methods

Attack Vectors:

• Remote Exploitation: An attacker can send a crafted HTTP GET request with a base64-encoded payload in the Cmd header.
• Input Manipulation: The vulnerability is triggered by manipulating the look parameter, which is concatenated into a PHP expression and executed.

Exploitation Methods:

• Crafted HTTP Requests: An attacker can craft an HTTP GET request with a malicious payload encoded in base64.
• Code Injection: The payload can include arbitrary PHP code, which will be executed by the server.

3. Affected Systems and Software Versions

Affected Software:

• InstantCMS version 1.6 and earlier.

Systems at Risk:

• Any web server running the affected versions of InstantCMS.
• Systems that have not applied the necessary patches or updates to mitigate this vulnerability.

4. Recommended Mitigation Strategies

Immediate Actions:

• Patching: Upgrade to a version of InstantCMS that is not affected by this vulnerability.
• Input Validation: Implement strict input validation and sanitation for all user-supplied data.
• Disable eval(): Avoid using the eval() function for executing dynamic code.

Long-Term Strategies:

• Regular Updates: Ensure that all software components are regularly updated and patched.
• Security Audits: Conduct regular security audits and code reviews to identify and mitigate similar vulnerabilities.
• Web Application Firewalls (WAF): Deploy WAFs to monitor and block malicious HTTP requests.

5. Impact on Cybersecurity Landscape

Immediate Impact:

• Data Breaches: Exploitation can lead to unauthorized access to sensitive data.
• System Compromise: Attackers can gain control over the web server, leading to further attacks.

Long-Term Impact:

• Reputation Damage: Organizations using vulnerable software may suffer reputational damage.
• Increased Attack Surface: Unpatched systems increase the overall attack surface, making them attractive targets for cybercriminals.

6. Technical Details for Security Professionals

Vulnerability Details:

• The eval() function in the search view handler of InstantCMS concatenates user input from the look parameter without proper sanitation.
• The Cmd header in the HTTP GET request is used to deliver the base64-encoded payload.

Exploitation Steps:

1. Craft the Payload: Encode the malicious PHP code in base64.
2. Send the Request: Use a tool like curl or a custom script to send the crafted HTTP GET request with the payload in the Cmd header.
3. Execute Code: The server executes the decoded PHP code, leading to arbitrary code execution.

Example Exploit Code:

<?php
$payload = base64_encode('<?php system($_GET["cmd"]); ?>');
$url = "http://vulnerable-site.com/search?look=" . urlencode($payload);
file_get_contents($url);
?>

References:

• Packet Storm Advisory
• Metasploit Module
• Exploit Database
• VulnCheck Advisory

Conclusion

CVE-2013-10051 represents a critical vulnerability in InstantCMS that can be exploited for remote PHP code execution. Organizations must prioritize patching and implementing robust input validation to mitigate this risk. Regular security audits and updates are essential to maintain a secure cybersecurity posture.