CVE-2002-0043 in sudo
Summary
by MITRE
sudo 1.6.0 through 1.6.3p7 does not properly clear the environment before calling the mail program, which could allow local users to gain root privileges by modifying environment variables and changing how the mail program is invoked.
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Analysis
by VulDB Data Team • 12/01/2024
The vulnerability described in CVE-2002-0043 represents a critical privilege escalation flaw in the sudo command utility affecting versions 1.6.0 through 1.6.3p7. This issue stems from improper environment variable handling during the execution of the mail program, creating a pathway for local attackers to exploit system security controls and elevate their privileges to root level access. The flaw specifically manifests when sudo executes the mail program, failing to properly sanitize or clear the environment variables that would normally be passed to the mail command. This oversight allows malicious users to manipulate variables such as MAILRC, MAILPATH, or other environment settings that influence how the mail program behaves, potentially leading to unauthorized privilege escalation.
From a technical perspective, the vulnerability operates through environment variable manipulation and process execution control mechanisms. When sudo invokes the mail program, it does not properly isolate the execution environment, leaving critical environment variables accessible to the invoked process. This behavior aligns with CWE-250, which describes improper privilege management, and CWE-78, which addresses improper neutralization of special elements used in OS commands. Attackers can exploit this by setting environment variables that cause the mail program to execute arbitrary commands or access files with elevated privileges, effectively bypassing sudo's intended security controls. The vulnerability demonstrates a classic case of insufficient input validation and environment sanitization, where the system fails to properly isolate the execution context of privileged operations.
The operational impact of this vulnerability extends beyond simple privilege escalation, as it fundamentally undermines the security model that sudo is designed to enforce. Local users who can execute sudo commands with limited privileges can leverage this flaw to gain root access, potentially compromising entire systems. The attack vector is particularly concerning because it requires minimal prerequisites - simply having access to execute sudo commands with appropriate permissions. This vulnerability enables attackers to execute arbitrary code with root privileges, potentially leading to complete system compromise, data exfiltration, or persistent access. The flaw essentially allows attackers to circumvent the principle of least privilege that sudo is intended to enforce, making it a critical security concern for any system running vulnerable versions of the sudo utility.
Mitigation strategies for CVE-2002-0043 focus on both immediate patching and operational security improvements. The primary solution involves upgrading to sudo versions 1.6.3p8 or later, where the environment variable clearing mechanism has been properly implemented to prevent the leakage of sensitive variables. Organizations should also implement comprehensive environment variable sanitization policies, ensuring that all privileged operations properly isolate execution contexts and clear potentially dangerous environment variables before executing external programs. System administrators should conduct thorough security audits to identify and remediate similar issues in other system components, particularly programs that execute external utilities and may be vulnerable to environment variable injection attacks. Additionally, implementing the principle of least privilege and monitoring sudo usage patterns can help detect anomalous behavior that might indicate exploitation attempts, aligning with ATT&CK technique T1068 which covers exploit for privilege escalation and T1548.1 which addresses abuse of sudo privileges.