Executive Summary

CVE-2016-20051 is a Cross-Site Request Forgery (CSRF) vulnerability affecting Snews CMS version 1.7 and earlier.

This vulnerability allows attackers to change administrator credentials without authentication by crafting malicious HTML forms that submit POST requests to the 'changeup' action.

An attacker tricks an authenticated administrator into visiting a page containing a hidden form that automatically submits and modifies the admin username and password parameters, enabling unauthorized administrative access.

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Compliance Impact

The vulnerability allows attackers to change administrator credentials without authentication, leading to unauthorized administrative access.

Such unauthorized access could potentially lead to data breaches or unauthorized data modifications, which may impact compliance with standards and regulations like GDPR or HIPAA that require protection of sensitive data and proper access controls.

However, the provided information does not explicitly describe the direct effects on compliance with these standards.

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Impact Analysis

This vulnerability can lead to unauthorized administrative account takeover without requiring the attacker to know existing credentials.

An attacker can gain full administrative access to the Snews CMS by changing the admin username and password, potentially allowing them to control the website content, settings, and user data.

Because the attack requires no privileges or user interaction beyond the administrator visiting a malicious page, it poses a significant security risk.

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Detection Guidance

This vulnerability can be detected by monitoring for suspicious POST requests targeting the sNews CMS changeup action endpoint, specifically requests to '/?action=process&task=changeup' that include parameters for changing administrator credentials such as 'uname', 'pass1', and 'pass2'.

Network or system administrators can use tools like packet capture (tcpdump, Wireshark) or web server logs to identify such POST requests.

• Use tcpdump to capture HTTP POST requests to the vulnerable endpoint: tcpdump -A -s 0 'tcp port 80 and (((ip[2:2] - ((ip[0]&0xf)<<2)) - ((tcp[12]&0xf0)>>2)) != 0)' | grep 'POST /?action=process&task=changeup'
• Check web server access logs for POST requests containing 'action=process&task=changeup' and parameters 'uname', 'pass1', or 'pass2'. For example, using grep: grep 'POST /?action=process&task=changeup' /var/log/apache2/access.log | grep -E 'uname=|pass1=|pass2='

Additionally, monitoring for unexpected changes in administrator credentials or unauthorized access attempts can help detect exploitation.

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Mitigation Strategies

Immediate mitigation steps include restricting access to the vulnerable sNews CMS administration interface and implementing protections against Cross-Site Request Forgery (CSRF) attacks.

• Apply patches or upgrade to a version of sNews CMS that addresses this CSRF vulnerability if available.
• Implement CSRF tokens in forms that perform sensitive actions like changing administrator credentials.
• Restrict administrative access to trusted IP addresses or networks to reduce exposure.
• Educate administrators to avoid visiting untrusted or suspicious web pages while authenticated to the CMS.

If immediate patching is not possible, consider disabling or restricting the 'changeup' action endpoint to prevent unauthorized credential changes.

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