CVE-2011-2195 in WebSVN
Summary
by MITRE • 10/26/2021
A flaw was found in WebSVN 2.3.2. Without prior authentication, if the 'allowDownload' option is enabled in config.php, an attacker can invoke the dl.php script and pass a well formed 'path' argument to execute arbitrary commands against the underlying operating system.
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Analysis
by VulDB Data Team • 10/30/2021
The vulnerability identified as CVE-2011-2195 represents a critical command injection flaw within WebSVN version 2.3.2 that fundamentally compromises system security when specific configuration settings are enabled. This issue arises from inadequate input validation and sanitization within the dl.php script, which processes file download requests without proper authentication mechanisms. The flaw specifically targets the 'allowDownload' configuration option in the config.php file, creating a dangerous attack vector when this setting is enabled, as it allows unauthenticated users to manipulate system commands through crafted input parameters.
The technical exploitation of this vulnerability occurs through the dl.php script's handling of the 'path' parameter, which fails to properly validate or sanitize user-supplied input before executing system commands. When an attacker crafts a malicious 'path' argument, the application directly incorporates this input into system execution calls without adequate filtering or encoding, enabling arbitrary command execution on the underlying operating system. This represents a classic command injection vulnerability that aligns with CWE-77, which catalogs improper neutralization of special elements used in commands. The vulnerability essentially allows an attacker to execute any command that the web server process has permissions to run, potentially providing complete system compromise.
The operational impact of this vulnerability extends far beyond simple unauthorized access, as it enables attackers to escalate privileges and execute malicious commands with the privileges of the web server process. This could result in data exfiltration, system compromise, service disruption, or even lateral movement within a network if the compromised web server has access to other systems. The vulnerability is particularly dangerous because it requires minimal authentication, making it accessible to anyone who can reach the WebSVN application. The attack surface is further expanded by the fact that the flaw operates at the system command level, potentially allowing attackers to access sensitive files, execute system utilities, or modify the web server's environment.
Organizations affected by this vulnerability should immediately implement several mitigation strategies to protect their systems. The primary recommendation involves disabling the 'allowDownload' option in config.php when it is not absolutely necessary, as this directly prevents the attack vector from being available. Additionally, implementing proper input validation and sanitization measures within the dl.php script would prevent malicious input from being executed as commands. Network-level protections such as web application firewalls can also help detect and block suspicious requests targeting the dl.php script. This vulnerability demonstrates the critical importance of secure coding practices and proper authentication mechanisms, as highlighted by ATT&CK technique T1059.001 for command and scripting interpreter and T1078 for valid accounts. Regular security audits and code reviews should be conducted to identify similar input validation weaknesses in web applications, particularly those handling user-supplied data that may be processed by system commands. The vulnerability also underscores the necessity of principle of least privilege in web server configurations, ensuring that web applications operate with minimal required permissions to reduce potential damage from successful exploitation attempts.