CVE-2010-0427 in sudo
Summary
by MITRE
sudo 1.6.x before 1.6.9p21, when the runas_default option is used, does not properly set group memberships, which allows local users to gain privileges via a sudo command.
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Analysis
by VulDB Data Team • 05/01/2026
The vulnerability identified as CVE-2010-0427 represents a critical privilege escalation flaw in the sudo command utility affecting versions 1.6.x prior to 1.6.9p21. This issue specifically manifests when the runas_default option is configured in sudoers files, creating a dangerous condition where local users can exploit improper group membership handling to elevate their privileges. The flaw resides in the core privilege management mechanism that governs how sudo processes execute commands under different user contexts, fundamentally undermining the security model that sudo is designed to enforce.
The technical root cause of this vulnerability stems from the improper handling of group memberships during privilege escalation operations. When sudo executes commands with the runas_default directive, it fails to correctly initialize or maintain the group context of the target user. This occurs because the sudo utility does not properly transfer or set the supplementary group IDs from the invoking user to the target user context. The flaw creates a scenario where the effective group identifiers remain unchanged or are set to the invoking user's group memberships rather than the target user's proper group context, allowing malicious users to leverage this misconfiguration for privilege escalation.
From an operational impact perspective, this vulnerability presents a significant threat to system security as local users who can execute sudo commands can potentially gain access to elevated privileges without proper authorization. The attack vector is particularly concerning because it leverages legitimate sudo functionality rather than requiring exploitation of other vulnerabilities. An attacker with access to a low-privilege account can craft specific sudo commands that exploit this group membership issue to gain access to resources and permissions that should be restricted to higher-privileged users. This vulnerability directly violates the principle of least privilege and can enable attackers to move laterally within a system or escalate to administrative access.
The security implications of this vulnerability align with CWE-276, which addresses improper privilege management, and can be categorized under ATT&CK technique T1068 for privilege escalation through local exploitation. This flaw represents a classic case of insufficient privilege separation where the system fails to properly enforce group-based access controls during privilege transitions. The vulnerability is particularly dangerous because it operates at the system level where group membership controls are fundamental to access management and security boundary enforcement.
Organizations should immediately implement mitigations including upgrading to sudo version 1.6.9p21 or later, which contains the necessary patches to properly handle group memberships during privilege escalation. Additionally, administrators should review sudoers configurations to minimize the use of runas_default directives and ensure proper group membership controls are enforced. The remediation process should include comprehensive testing of sudo configurations to verify that group memberships are correctly handled and that privilege escalation is properly restricted according to security policies. System administrators should also monitor for unauthorized sudo usage patterns that might indicate exploitation attempts and implement proper logging and alerting mechanisms to detect potential abuse of this vulnerability.