CVE-2013-6889 in Rush
Summary
by MITRE
GNU Rush 1.7 does not properly drop privileges, which allows local users to read arbitrary files via the --lint option.
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Analysis
by VulDB Data Team • 03/21/2022
The vulnerability identified as CVE-2013-6889 affects GNU Rush version 1.7, a command-line interface for the GNU operating system that provides a rich set of features for shell command execution and management. This flaw represents a critical privilege escalation issue that stems from improper privilege handling during the execution of specific command-line options. The GNU Rush utility is designed to provide enhanced shell functionality while maintaining security boundaries, but this particular vulnerability undermines those security mechanisms by failing to correctly relinquish elevated privileges when processing certain inputs.
The technical flaw manifests specifically through the --lint option, which is intended to perform syntax checking on shell commands and scripts. When invoked with this option, the application does not properly drop root privileges that it may have acquired during startup or through other mechanisms. This improper privilege management creates a condition where a local user can exploit the application to read arbitrary files on the system that would normally be restricted to privileged access. The vulnerability operates under the principle of privilege escalation by leveraging the application's failure to properly transition from elevated to restricted user contexts.
The operational impact of this vulnerability is significant for systems running GNU Rush 1.7, particularly in multi-user environments where local users might not have direct access to sensitive system files. An attacker with local access can exploit this flaw to gain unauthorized reading access to files that should only be accessible to root or specific privileged users. This capability can lead to information disclosure attacks where sensitive data such as configuration files, password hashes, or system credentials might be extracted from the compromised system. The vulnerability affects the fundamental security model of the application and can potentially enable further attacks if sensitive information is discovered.
This vulnerability maps to CWE-276, which describes improper privilege management, and aligns with several ATT&CK techniques including privilege escalation and credential access. The flaw demonstrates a failure in the principle of least privilege enforcement, where the application maintains elevated privileges longer than necessary and does not properly transition to restricted user contexts. Organizations should immediately apply the vendor-provided patch that addresses the privilege dropping mechanism in the --lint option. Additionally, system administrators should implement monitoring for unusual file access patterns and consider restricting local user access to GNU Rush if the application is not essential for legitimate administrative tasks. The mitigation strategy should also include regular security audits to ensure proper privilege handling across all system utilities and applications.