CVE-2017-17536 Explained : Impact and Mitigation

Phabricator before November 10, 2017, had a vulnerability that allowed unauthorized code execution through specific flags in the Mercurial hg program.

Understanding CVE-2017-17536

This CVE describes a security issue in Phabricator that could be exploited by malicious actors to execute arbitrary code.

What is CVE-2017-17536?

Prior to November 10, 2017, Phabricator did not prevent the use of certain flags with the Mercurial hg program, enabling attackers to execute unauthorized code through the web user interface.

The Impact of CVE-2017-17536

This vulnerability could be exploited by navigating to a branch with specific names, leading to the execution of unauthorized code.

Technical Details of CVE-2017-17536

Phabricator's vulnerability allowed for unauthorized code execution through the following details:

Vulnerability Description

The issue stemmed from the lack of measures to block --config and --debugger flags in the Mercurial hg program.

Affected Systems and Versions

Product: Not applicable
Vendor: Not applicable
Versions: Not applicable

Exploitation Mechanism

Malicious individuals could exploit the web UI by accessing branches with names starting with --config= or --debugger= sub-strings.

Mitigation and Prevention

To address CVE-2017-17536, consider the following steps:

Immediate Steps to Take

Update Phabricator to a version that includes a fix for this vulnerability.
Monitor for any unauthorized code execution attempts.

Long-Term Security Practices

Regularly update and patch Phabricator to address security vulnerabilities.
Implement strict access controls to prevent unauthorized access to sensitive functionalities.

Patching and Updates

Ensure that Phabricator is regularly updated with the latest security patches to mitigate potential risks.