CVE-2017-8418 in RuboCop
Summary
by MITRE
RuboCop 0.48.1 and earlier does not use /tmp in safe way, allowing local users to exploit this to tamper with cache files belonging to other users.
Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.
Analysis
by VulDB Data Team • 12/06/2022
The vulnerability identified as CVE-2017-8418 affects RuboCop versions 0.48.1 and earlier, presenting a significant security flaw in how the tool handles temporary file operations. This issue stems from the application's improper utilization of the /tmp directory for cache file storage, creating opportunities for local privilege escalation and cross-user file manipulation. The flaw specifically manifests when RuboCop creates cache files in the system's temporary directory without implementing proper security measures to isolate user-specific data. This design oversight allows malicious local users to potentially access, modify, or manipulate cache files that should remain isolated to their respective user accounts, fundamentally compromising the integrity of the tool's operation and the security boundaries between different users on the same system.
The technical implementation of this vulnerability involves RuboCop's failure to properly secure temporary file creation processes within the /tmp directory. When the application generates cache files during code analysis operations, it does not employ mechanisms such as secure temporary file creation functions, proper file permissions, or user-specific subdirectory isolation. This behavior creates predictable file paths that can be exploited by attackers to manipulate cache contents, potentially leading to arbitrary code execution or data corruption. The vulnerability aligns with CWE-377, which addresses insecure temporary file handling, and demonstrates poor secure coding practices that violate fundamental security principles for temporary file management. Attackers can exploit this weakness by creating symbolic links or by directly accessing cache files to inject malicious content that will be processed by subsequent RuboCop executions.
The operational impact of CVE-2017-8418 extends beyond simple cache file manipulation, potentially enabling more serious security consequences within development environments where RuboCop is frequently used. In multi-user systems or shared development environments, this vulnerability allows unauthorized users to compromise the code analysis process, potentially introducing false positives or negatives in code quality checks. The attack surface becomes particularly concerning in continuous integration environments where RuboCop is automatically invoked, as attackers could manipulate the analysis results to hide malicious code or bypass security checks. This vulnerability also represents a significant risk in environments where developers trust RuboCop's output without additional verification, as compromised cache files could lead to security misconfigurations or the introduction of vulnerabilities into production code. The flaw's impact is further amplified by the fact that cache files are often created with predictable naming conventions and locations, making exploitation relatively straightforward for attackers familiar with the tool's operation.
Mitigation strategies for CVE-2017-8418 should focus on both immediate remediation and long-term architectural improvements to prevent similar vulnerabilities. The most direct solution involves upgrading to RuboCop versions 0.49.0 or later, where the developers have implemented proper temporary file handling mechanisms including secure file creation and user isolation. Organizations should also consider implementing additional security controls such as restricting write permissions to the /tmp directory, implementing proper file ownership controls, and establishing monitoring for unauthorized cache file modifications. The vulnerability's remediation aligns with ATT&CK technique T1059.001 for command and scripting interpreter, as attackers could potentially leverage this flaw to execute malicious code through manipulated cache files. System administrators should also consider implementing process isolation and privilege separation measures to limit the potential impact of any successful exploitation attempts, ensuring that even if an attacker gains access to cache files, they cannot escalate privileges or access sensitive system resources beyond the scope of the compromised application.