CVE-2014-9462 in Mercurial
Summary
by MITRE
The _validaterepo function in sshpeer in Mercurial before 3.2.4 allows remote attackers to execute arbitrary commands via a crafted repository name in a clone command.
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Analysis
by VulDB Data Team • 05/02/2022
The vulnerability identified as CVE-2014-9462 represents a critical command injection flaw within the Mercurial distributed version control system. This vulnerability specifically affects the _validaterepo function within the sshpeer module, which handles repository operations over SSH connections. The flaw exists in Mercurial versions prior to 3.2.4 and enables remote attackers to execute arbitrary commands on systems running vulnerable versions of the software. The vulnerability arises from insufficient input validation when processing repository names during clone operations, creating a path for malicious input to be interpreted as executable commands rather than simple repository identifiers.
The technical implementation of this vulnerability stems from improper sanitization of repository names in the SSH peer functionality. When a user attempts to clone a repository using SSH, the system calls the _validaterepo function to validate the repository name. However, this validation process fails to properly escape or sanitize special characters that could be interpreted by the underlying shell. Attackers can craft malicious repository names containing shell metacharacters such as semicolons, pipes, or command substitutions that get executed when the system processes the clone command. This type of vulnerability falls under CWE-78, which specifically addresses OS Command Injection, and represents a classic example of insufficient input sanitization in security-critical code paths.
The operational impact of this vulnerability extends beyond simple command execution, as it can enable full system compromise when attackers exploit it against systems running vulnerable Mercurial versions. Remote attackers can leverage this vulnerability to execute arbitrary code with the privileges of the user running the Mercurial process, potentially leading to complete system takeover. The vulnerability is particularly dangerous in environments where Mercurial is used for collaborative software development and where repository operations are performed over SSH connections. The attack surface is broad since any system that allows remote cloning of repositories through SSH is potentially vulnerable, making this an attractive target for malicious actors seeking to compromise development infrastructure. This vulnerability directly aligns with ATT&CK technique T1059.001, which covers command and scripting interpreter execution through shell commands.
Mitigation strategies for CVE-2014-9462 primarily focus on immediate version upgrades to Mercurial 3.2.4 or later, which contain the necessary patches to address the command injection vulnerability. Organizations should also implement network segmentation and access controls to limit exposure of systems running vulnerable Mercurial versions, particularly those accessible over SSH. Additionally, administrators should consider implementing input validation policies at the network level and monitoring for suspicious repository naming patterns in system logs. The vulnerability highlights the importance of proper input sanitization in security-critical applications and serves as a reminder of the potential consequences of inadequate validation of user-provided data in shell command contexts. Security teams should also review and test their existing security controls to ensure that similar vulnerabilities do not exist in other components of their software infrastructure, as this represents a pattern that could manifest in other applications handling user input through shell operations.