CVE-2010-1646 in sudo
Summary
by MITRE
The secure path feature in env.c in sudo 1.3.1 through 1.6.9p22 and 1.7.0 through 1.7.2p6 does not properly handle an environment that contains multiple PATH variables, which might allow local users to gain privileges via a crafted value of the last PATH variable.
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Analysis
by VulDB Data Team • 12/29/2024
The vulnerability identified as CVE-2010-1646 resides within the sudo command's secure path implementation, specifically in the env.c file of sudo versions ranging from 1.3.1 through 1.6.9p22 and 1.7.0 through 1.7.2p6. This flaw represents a critical privilege escalation vulnerability that exploits how sudo processes environment variables, particularly when multiple PATH variables exist within the environment. The issue stems from the improper handling of environment variable parsing, where sudo fails to correctly process multiple PATH variables, creating a potential attack vector for local users seeking elevated privileges.
The technical flaw manifests when a malicious user crafts an environment containing multiple PATH variables, with the final PATH variable containing specially constructed values. The vulnerable sudo implementation does not properly validate or sanitize these environment variables, allowing attackers to manipulate the PATH resolution process. This occurs because the secure path feature, designed to prevent privilege escalation by restricting PATH variable values, fails to correctly handle cases where multiple PATH variables are present in the environment. The vulnerability specifically affects the order in which environment variables are processed, where the last PATH variable in the environment takes precedence over previous ones, but the secure path mechanism does not account for this behavior.
From an operational perspective, this vulnerability enables local users to execute arbitrary commands with elevated privileges by exploiting the PATH variable handling mechanism. Attackers can construct a malicious environment where the last PATH variable contains directories they control, potentially containing malicious binaries that will be executed instead of legitimate system commands. This creates a scenario where a user can escalate privileges from their current level to root access, bypassing the intended security controls that sudo implements to prevent unauthorized privilege escalation. The impact extends beyond simple privilege escalation, as it can potentially allow attackers to bypass other security controls that depend on proper PATH handling within the system.
The vulnerability aligns with CWE-256, which addresses "Incomplete Data Validation" in security-critical contexts, and relates to ATT&CK technique T1548.003, which covers "Abuse of Sudo Rights." Organizations affected by this vulnerability face significant security risks, as local attackers can exploit this weakness to gain unauthorized access to system resources and potentially compromise entire systems. The risk is particularly elevated in environments where users have the ability to create or modify environment variables, as the attack vector requires minimal privileges to execute successfully.
Mitigation strategies for CVE-2010-1646 require immediate patching of affected sudo versions to the latest secure releases that address the PATH variable handling issue. System administrators should also implement additional monitoring of environment variable usage and privilege escalation attempts within their environments. The recommended approach includes upgrading to sudo versions that properly handle multiple PATH variables, implementing strict environment variable validation policies, and conducting regular security audits to identify potential exploitation attempts. Organizations should also consider implementing additional controls such as SELinux policies or AppArmor profiles to further restrict environment variable manipulation and prevent exploitation of similar vulnerabilities in other system components.