CVE-2008-5920 in WebSVN
Summary
by MITRE
The create_anchors function in utils.inc in WebSVN 1.x allows remote attackers to execute arbitrary PHP code via a crafted username that is processed by the preg_replace function with the eval switch.
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Analysis
by VulDB Data Team • 11/08/2024
The vulnerability identified as CVE-2008-5920 represents a critical remote code execution flaw within the WebSVN 1.x content management system. This issue resides in the create_anchors function located within the utils.inc file, which serves as a core utility component for the application. The vulnerability arises from improper input validation and unsafe handling of user-provided data, creating a pathway for malicious actors to inject and execute arbitrary PHP code on the affected server. WebSVN, being a web-based interface for viewing Subversion repositories, typically operates in environments where it processes user inputs for generating navigation links and anchor points, making this flaw particularly dangerous as it can be exploited through normal user interaction patterns.
The technical exploitation of this vulnerability occurs through the manipulation of the preg_replace function with the eval modifier, a dangerous combination that enables code injection attacks. When a crafted username is submitted to the system, the create_anchors function processes this input without proper sanitization, allowing specially crafted payloads to be interpreted as executable PHP code. The preg_replace function with the eval switch essentially transforms user input into executable code, bypassing normal security boundaries and allowing attackers to execute arbitrary commands on the server. This vulnerability maps directly to CWE-94, which describes "Improper Control of Generation of Code ('Code Injection')" and specifically relates to CWE-74, "Improper Neutralization of Special Elements in Output Used by a Downstream Component ('Injection')". The attack vector is classified as remote, meaning that an attacker can exploit this vulnerability without requiring physical access to the system, making it particularly severe in web-facing environments.
The operational impact of this vulnerability extends beyond simple code execution, as it provides attackers with complete control over the affected WebSVN server. Successful exploitation can lead to full system compromise, data theft, persistence mechanisms, and potential lateral movement within the network. Attackers can leverage this vulnerability to establish backdoors, exfiltrate repository data, modify or delete source code, and potentially use the compromised server as a staging point for further attacks. The vulnerability affects all versions of WebSVN 1.x, making it a widespread issue that would impact numerous organizations relying on this software for version control repository management. This type of vulnerability is particularly concerning in the context of ATT&CK framework's T1059.007, which covers "Command and Scripting Interpreter: PowerShell," and T1566.001, "Phishing: Spearphishing Attachment," as attackers can use this vulnerability to deploy malicious payloads and establish persistent access to systems.
The recommended mitigations for this vulnerability involve immediate patching of the affected WebSVN installations, as the developers have released updates addressing this specific flaw. Organizations should also implement input validation measures to sanitize all user-provided data before processing, particularly when using functions that can execute code dynamically. Network segmentation and access controls should be implemented to limit exposure of WebSVN applications to untrusted users. Additionally, monitoring for suspicious user activity and anomalous code execution patterns can help detect exploitation attempts. The vulnerability serves as a stark reminder of the importance of secure coding practices, particularly regarding the use of dynamic code execution functions and the necessity of proper input validation. Organizations should conduct comprehensive security assessments of their WebSVN installations and ensure that all third-party applications are kept up to date with the latest security patches to prevent similar vulnerabilities from being exploited in their environments.