CVE-2017-16926 in Ohcount
Summary
by MITRE
Ohcount 3.0.0 is prone to a command injection via specially crafted filenames containing shell metacharacters, which can be exploited by an attacker (providing a source tree for Ohcount processing) to execute arbitrary code as the user running Ohcount.
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Analysis
by VulDB Data Team • 12/09/2019
The vulnerability identified as CVE-2017-16926 affects Ohcount version 3.0.0, a source code analysis tool designed to count lines of code and identify programming languages within source trees. This critical security flaw stems from inadequate input validation and sanitization within the tool's filename processing logic, creating a command injection vulnerability that can be exploited by malicious actors. The vulnerability specifically manifests when Ohcount processes source trees containing filenames that include shell metacharacters, which are typically used to execute shell commands or manipulate shell behavior.
The technical implementation of this vulnerability resides in the tool's failure to properly escape or sanitize user-supplied filenames before incorporating them into shell commands. When Ohcount encounters a filename containing special shell characters such as semicolons, pipes, or backticks, these characters are interpreted by the underlying shell as command separators or operators rather than literal filename characters. This allows an attacker to inject malicious shell commands that get executed with the privileges of the user running the Ohcount process. The vulnerability maps to CWE-78, which specifically addresses Improper Neutralization of Special Elements used in OS Commands, and represents a classic command injection flaw that has been consistently identified across numerous software systems throughout the industry.
The operational impact of this vulnerability is severe and far-reaching, as it enables remote code execution in the context of the user running Ohcount. An attacker who can influence the source tree being processed by Ohcount can craft filenames that, when processed, will execute arbitrary commands on the system. This could lead to complete system compromise, data exfiltration, privilege escalation, or the installation of backdoors. The vulnerability is particularly dangerous in environments where Ohcount is used to analyze untrusted source code repositories, such as in continuous integration systems, code review platforms, or automated security scanning tools. The attack vector requires minimal privileges to exploit and can be automated, making it a high-value target for attackers seeking persistent access to systems.
Mitigation strategies for this vulnerability should focus on immediate remediation through updating to a patched version of Ohcount where the command injection has been addressed. Organizations should implement strict input validation and sanitization measures, ensuring that all filenames are properly escaped before being used in shell contexts. The principle of least privilege should be enforced, running Ohcount with minimal necessary permissions and avoiding execution as root or administrative users. Additionally, input filtering mechanisms should be implemented to detect and reject filenames containing shell metacharacters, though this approach must be carefully balanced against legitimate use cases. Security monitoring should be enhanced to detect unusual command execution patterns that might indicate exploitation attempts. From an ATT&CK perspective, this vulnerability aligns with techniques involving command and scripting interpreter execution, and organizations should consider implementing defensive measures such as application whitelisting, process monitoring, and network segmentation to reduce the attack surface and limit the potential impact of successful exploitation attempts.