CVE-2018-20235 in SourceTree
Summary
by MITRE
There was an argument injection vulnerability in Atlassian Sourcetree for Windows from version 0.5a before version 3.0.15 via filenames in Mercurial repositories. A remote attacker with permission to commit to a Mercurial repository linked in Sourcetree for Windows is able to exploit this issue to gain code execution on the system.
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Analysis
by VulDB Data Team • 07/29/2023
The vulnerability CVE-2018-20235 represents a critical argument injection flaw in Atlassian Sourcetree for Windows that affected versions prior to 3.0.15. This issue specifically targeted the handling of filenames within Mercurial repositories, creating a pathway for remote code execution when a malicious actor gained commit permissions to a linked repository. The vulnerability stems from improper input validation and sanitization of repository filenames, which are processed as command-line arguments without adequate escaping or filtering mechanisms. This type of flaw falls under CWE-77 which specifically addresses command injection vulnerabilities where user-supplied data is directly incorporated into system commands without proper sanitization. The attack vector is particularly concerning because it requires only commit permissions to a repository, making it accessible to attackers who may not have full administrative access to the system.
The technical exploitation of this vulnerability occurs when Sourcetree processes filenames from Mercurial repositories and incorporates them into system commands without proper argument separation or escaping. When a malicious user commits a specially crafted filename that contains shell metacharacters or command separators, the application fails to properly sanitize this input before executing system commands. This creates an environment where arbitrary commands can be executed with the privileges of the user running Sourcetree, potentially leading to complete system compromise. The vulnerability is classified as a remote code execution threat because the malicious input can be introduced through repository commits, allowing attackers to execute code on the target system without requiring local access or physical presence. This aligns with ATT&CK technique T1059 which covers command and scripting interpreter, specifically targeting the execution of system commands through vulnerable applications.
The operational impact of CVE-2018-20235 extends beyond immediate code execution capabilities to encompass broader security implications for development environments and source code management systems. Organizations using Atlassian Sourcetree for Windows with Mercurial repositories face significant risk when the application is used by multiple developers or when repository permissions are not properly managed. The vulnerability creates a persistent threat vector that can be exploited through legitimate repository operations, making detection and prevention more challenging. Attackers can leverage this vulnerability to establish persistent access, escalate privileges, or deploy additional malicious tools within the compromised environment. The risk is amplified in enterprise settings where Sourcetree is widely deployed across development teams, potentially affecting multiple systems simultaneously. Organizations implementing security controls must consider the implications of this vulnerability in their overall security posture, particularly regarding code repository management and access controls.
Mitigation strategies for CVE-2018-20235 primarily focus on immediate patching and access control improvements. The most effective solution is upgrading to Atlassian Sourcetree version 3.0.15 or later, which includes proper input sanitization and argument handling for repository filenames. System administrators should implement strict repository access controls, limiting commit permissions to trusted individuals and conducting regular audits of repository access. Additional protective measures include monitoring repository commits for suspicious filename patterns and implementing network-based detection systems to identify potential exploitation attempts. Organizations should also consider implementing application whitelisting policies that restrict the execution of unauthorized command-line tools and establish secure coding practices for applications handling user-supplied data. The vulnerability highlights the importance of input validation and proper argument handling in preventing command injection attacks, reinforcing industry best practices outlined in security frameworks such as the OWASP Top Ten and NIST Cybersecurity Framework. Regular security assessments and vulnerability scanning should include checks for similar argument injection vulnerabilities in other source code management tools and development environments to prevent similar incidents.