CVE-2010-3847 in C Library
Summary
by MITRE
elf/dl-load.c in ld.so in the GNU C Library (aka glibc or libc6) through 2.11.2, and 2.12.x through 2.12.1, does not properly handle a value of $ORIGIN for the LD_AUDIT environment variable, which allows local users to gain privileges via a crafted dynamic shared object (DSO) located in an arbitrary directory.
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Analysis
by VulDB Data Team • 12/29/2024
The vulnerability described in CVE-2010-3847 resides within the dynamic linker component of the GNU C Library known as ld.so, specifically in the elf/dl-load.c file. This flaw affects glibc versions prior to 2.11.3 and 2.12.2, creating a privilege escalation vector through improper handling of the $ORIGIN token when used with the LD_AUDIT environment variable. The issue manifests when a malicious actor crafts a dynamic shared object that leverages the $ORIGIN mechanism to specify audit library paths, enabling arbitrary code execution with elevated privileges.
The technical root cause of this vulnerability stems from how the dynamic linker processes the $ORIGIN token within the LD_AUDIT environment variable. When $ORIGIN is used in the context of audit library paths, the system fails to properly validate or sanitize the path resolution, allowing attackers to manipulate the audit library loading process. This occurs because the dynamic linker does not adequately restrict path traversal or validate that the specified audit libraries originate from trusted locations. The flaw operates under the principle of insufficient input validation and path sanitization, which aligns with CWE-22 - Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal') and CWE-78 - Improper Neutralization of Special Elements used in OS Command.
The operational impact of this vulnerability is significant as it enables local privilege escalation attacks. An attacker with low-privilege access can craft a malicious DSO file and place it in an arbitrary directory, then use the LD_AUDIT environment variable with $ORIGIN to load this audit library. The dynamic linker's failure to properly resolve paths means the system will execute the malicious audit library with the privileges of the process that initiated the audit loading. This creates a direct path to privilege escalation, potentially allowing attackers to gain root access or elevated system privileges. The attack vector is particularly dangerous because it requires minimal user interaction beyond setting environment variables and executing a program that uses dynamic linking.
Mitigation strategies for CVE-2010-3847 involve multiple layers of security controls. The primary remediation is upgrading to glibc versions 2.11.3 or 2.12.2 and later, which contain the necessary patches to properly handle $ORIGIN tokens in LD_AUDIT. System administrators should also implement strict environment variable controls, particularly disabling or restricting the use of LD_AUDIT in production environments where possible. Additionally, the principle of least privilege should be enforced by ensuring that applications do not run with unnecessary privileges, and by implementing proper file system permissions to limit where malicious DSOs can be placed. Security tools should monitor for suspicious LD_AUDIT usage patterns, and organizations should consider implementing application whitelisting to prevent execution of unauthorized shared libraries. This vulnerability demonstrates the critical importance of proper path validation in system-level components and aligns with ATT&CK technique T1068 - Exploitation for Privilege Escalation, specifically targeting weaknesses in dynamic library loading mechanisms.