CVE-2014-0106 in sudo
Summary
by MITRE
Sudo 1.6.9 before 1.8.5, when env_reset is disabled, does not properly check environment variables for the env_delete restriction, which allows local users with sudo permissions to bypass intended command restrictions via a crafted environment variable.
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Analysis
by VulDB Data Team • 05/07/2026
The vulnerability identified as CVE-2014-0106 represents a critical privilege escalation flaw in the sudo command utility affecting versions prior to 1.8.5. This issue specifically manifests when the env_reset configuration option is disabled, creating a dangerous bypass mechanism that undermines the security controls designed to restrict user command execution. The flaw resides in the improper validation of environment variables within the sudo environment handling mechanism, allowing malicious actors to circumvent intended restrictions through carefully crafted environmental modifications.
The technical implementation of this vulnerability stems from a fundamental flaw in sudo's environment variable processing logic. When env_reset is disabled, sudo should enforce strict controls over environment variables through the env_delete configuration directive, which is designed to remove potentially dangerous variables from the execution environment. However, the implementation fails to properly validate or sanitize environment variables, creating a path where attackers can inject malicious variables that bypass these protective measures. This flaw operates at the core of sudo's privilege management system, where environment variables serve as the primary means of controlling execution context and command behavior.
The operational impact of CVE-2014-0106 extends far beyond simple privilege escalation, as it allows local users who possess sudo permissions to effectively bypass the security controls that administrators have implemented to restrict command execution. An attacker with access to a system where sudo is configured with specific command restrictions can exploit this vulnerability to execute arbitrary commands with elevated privileges, potentially gaining access to sensitive system resources, modifying critical files, or establishing persistent access. The vulnerability is particularly dangerous because it operates silently within the legitimate sudo execution flow, making detection difficult and allowing attackers to maintain stealth while exploiting the system.
This vulnerability maps directly to CWE-225, which describes "Improper Handling of Environment Variables," and aligns with several ATT&CK techniques including T1068 for "Exploitation for Privilege Escalation" and T1548.003 for "Abuse of Sudo Rights." The flaw demonstrates how seemingly minor configuration options can create significant security gaps when combined with improper input validation. Organizations running affected sudo versions face a critical risk of unauthorized privilege escalation, where attackers can leverage this vulnerability to compromise entire systems. The impact is particularly severe in environments where sudo is used extensively for administrative tasks, as it provides attackers with a reliable method for escalating privileges without triggering traditional security monitoring mechanisms.
The recommended mitigation strategy involves immediate upgrade to sudo version 1.8.5 or later, where the environment variable validation has been properly implemented to address this specific flaw. Additionally, system administrators should review and properly configure sudo's environment handling settings, ensuring that env_reset is enabled and that appropriate env_delete restrictions are in place. Organizations should also implement monitoring for unusual sudo usage patterns and consider implementing additional security controls such as sudo logging and audit mechanisms to detect potential exploitation attempts. Regular security assessments of sudo configurations and privilege assignments are essential to prevent exploitation of similar vulnerabilities in the future.