CVE-2006-3633 in shiela
Summary
by MITRE
OSSP shiela 1.1.5 and earlier allows remote authenticated users to execute arbitrary commands on the CVS server via shell metacharacters in a filename that is committed.
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Analysis
by VulDB Data Team • 08/01/2018
The vulnerability described in CVE-2006-3633 represents a critical command injection flaw within the OSSP shiela version 1.1.5 and earlier. This security issue affects the CVS (Concurrent Versions System) server component that processes file names during commit operations. The vulnerability arises from inadequate input validation and sanitization mechanisms within the shiela utility, which is designed to handle various file operations within the CVS framework. When authenticated users commit files with specially crafted filenames containing shell metacharacters, the system fails to properly escape or filter these characters before processing them in shell commands.
The technical implementation of this vulnerability stems from the improper handling of user-supplied data within the CVS server's file name processing logic. When a user commits a file with a filename containing characters such as semicolons, ampersands, or backticks, these metacharacters are interpreted by the underlying shell during command execution. This occurs because the system does not adequately sanitize or escape the filename before incorporating it into shell commands that are executed on the server. The vulnerability specifically targets the command execution phase where file names are processed through shell invocations, creating an environment where malicious input can be transformed into arbitrary command execution.
This flaw has significant operational impact on organizations relying on CVS for version control management. Remote authenticated attackers can leverage this vulnerability to execute arbitrary commands on the CVS server with the privileges of the user account running the server process. The attack vector requires only authentication to the CVS system, making it particularly dangerous as it can be exploited by insiders or compromised accounts. The consequences extend beyond simple command execution to include potential data exfiltration, system compromise, and unauthorized access to source code repositories. Organizations may face complete system compromise if the CVS server runs with elevated privileges, as the executed commands could potentially escalate to root or administrative access levels.
The vulnerability aligns with CWE-78, which specifically addresses "Improper Neutralization of Special Elements used in an OS Command" and maps to ATT&CK technique T1059.001 for command and script execution. Organizations should implement immediate mitigations including upgrading to shiela version 1.1.6 or later where this vulnerability has been patched, applying proper input validation and sanitization for all user-supplied file names, and implementing strict filename character restrictions. Additional defensive measures include running the CVS server with minimal privileges, implementing network segmentation, and monitoring for suspicious command execution patterns. The fix typically involves ensuring that all user-provided filenames are properly escaped or quoted before being passed to shell commands, preventing interpretation of metacharacters as shell operators. Organizations should also consider implementing automated scanning tools to detect similar vulnerabilities in other legacy systems and establish robust input validation policies across all server-side applications.