CVE-2014-2886 in GKSu
Summary
by MITRE
GKSu 2.0.2, when sudo-mode is not enabled, uses " (double quote) characters in a gksu-run-helper argument, which allows attackers to execute arbitrary commands in certain situations involving an untrusted substring within this argument, as demonstrated by an untrusted filename encountered during installation of a VirtualBox extension pack.
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Analysis
by VulDB Data Team • 03/12/2019
The vulnerability identified as CVE-2014-2886 affects GKSu version 2.0.2, a graphical frontend for the sudo command designed to provide user-friendly privilege escalation. This flaw exists specifically when the sudo-mode is disabled within the application configuration, creating a critical security gap that enables command injection attacks. The vulnerability stems from improper input validation and sanitization within the gksu-run-helper component, which processes user-supplied arguments without adequate protection against malicious input sequences. When an attacker can influence the filename parameter during VirtualBox extension pack installation, they can exploit this weakness to execute arbitrary commands with elevated privileges, effectively bypassing the intended security boundaries of the graphical sudo interface.
The technical root cause of this vulnerability lies in the improper handling of double quote characters within the gksu-run-helper argument processing. According to CWE-74, this represents a weakness in input validation where special characters are not properly escaped or sanitized, creating a command injection vector. The vulnerability manifests when the application passes user-controllable input directly to system commands without adequate filtering or escaping mechanisms. The specific context involves the installation process of VirtualBox extension packs, where filenames are processed and potentially passed to helper applications without proper sanitization. This creates an environment where an attacker can manipulate the filename argument to inject additional commands that will be executed by the underlying system with the privileges of the target user. The attack vector demonstrates a classic command injection vulnerability where the attacker leverages the lack of input sanitization to append malicious commands to legitimate operations.
The operational impact of CVE-2014-2886 is severe and potentially devastating for systems running affected versions of GKSu. Attackers can exploit this vulnerability to execute arbitrary code with elevated privileges, potentially leading to complete system compromise, privilege escalation, and persistent access to the target environment. The vulnerability affects systems where GKSu is used for privilege escalation, particularly in desktop environments where users might install software packages that trigger the vulnerable code path. In the context of VirtualBox extension pack installation, this vulnerability allows attackers to execute malicious commands during what should be a benign software installation process, making the attack surface particularly broad. The risk is amplified because the exploitation does not require specialized knowledge of the system architecture, as the vulnerability exists in the application's handling of user input during standard operations. According to ATT&CK framework, this vulnerability maps to T1068 (Exploitation for Privilege Escalation) and T1059 (Command and Scripting Interpreter), representing both the means of privilege escalation and the execution of malicious commands through the system's command interpreter.
Mitigation strategies for CVE-2014-2886 require immediate action to address the underlying input validation issues within GKSu. The primary solution involves updating to a patched version of GKSu that properly sanitizes input parameters before passing them to system commands, ensuring that special characters are properly escaped or filtered. Organizations should disable sudo-mode in GKSu configuration when it is not required, as this significantly reduces the attack surface by preventing the use of potentially vulnerable code paths. System administrators should implement input validation policies that specifically target command injection vectors, ensuring that user-supplied data cannot contain characters that would enable command concatenation. Additionally, implementing proper privilege separation and least-privilege principles can limit the damage if exploitation occurs. The vulnerability also highlights the importance of secure coding practices, particularly in applications that handle user input and execute system commands. Regular security audits and code reviews should specifically examine how applications handle command-line arguments and user-supplied data to prevent similar issues in other components. Organizations should also consider implementing application whitelisting policies that restrict which applications can execute commands with elevated privileges, reducing the potential impact of such vulnerabilities.