CVE-2017-6906 in SiberianCMS
Summary
by MITRE
An issue was discovered in SiberianCMS before 4.10.0. The vulnerability exists due to insufficient filtration of user-supplied data (log) passed to the the "SiberianCMS-master/errors/500.php" URL. An attacker could execute arbitrary HTML and script code in a browser in the context of the vulnerable website.
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Analysis
by VulDB Data Team • 09/07/2020
The vulnerability identified as CVE-2017-6906 represents a critical cross-site scripting flaw within SiberianCMS versions prior to 4.10.0. This security weakness stems from inadequate input validation mechanisms that fail to properly sanitize user-supplied data before processing. The specific point of failure occurs within the error handling mechanism at the path "SiberianCMS-master/errors/500.php" where log data is directly incorporated into the web response without appropriate sanitization measures. This allows malicious actors to inject malicious content that executes within the context of legitimate user sessions.
The technical implementation of this vulnerability aligns with CWE-79, which categorizes cross-site scripting as a code injection flaw that occurs when untrusted data is incorporated into web pages without proper validation or encoding. The flaw specifically manifests when the application processes error logs containing user-supplied input and subsequently renders this data in the browser context. Attackers can exploit this by crafting malicious input that gets logged and then displayed through the 500 error page, effectively bypassing normal security controls that protect against direct script injection in other application areas.
From an operational impact perspective, this vulnerability creates significant risks for organizations using affected SiberianCMS versions. The ability to execute arbitrary HTML and script code in the context of the vulnerable website allows attackers to perform session hijacking, deface web pages, steal sensitive information, or redirect users to malicious sites. The attack vector is particularly concerning because it leverages legitimate error handling mechanisms rather than requiring direct exploitation of application logic vulnerabilities. This makes detection more challenging and increases the potential for persistent attacks that can remain undetected for extended periods.
The exploitation of this vulnerability follows patterns consistent with ATT&CK technique T1566, which covers social engineering tactics including the use of malicious content in web applications. Security professionals should implement comprehensive input validation and output encoding as primary mitigation strategies. The recommended approach involves implementing strict sanitization of all user-supplied data before it is processed or displayed, particularly in error handling and logging components. Organizations should also consider implementing content security policies to further limit the execution of unauthorized scripts and ensure that all user inputs undergo proper validation before being incorporated into web responses. The most effective long-term solution requires upgrading to SiberianCMS version 4.10.0 or later, which includes proper input sanitization mechanisms that prevent this class of vulnerability from occurring.