CVE-2011-0536 in Red Hat
Summary
by MITRE
Multiple untrusted search path vulnerabilities in elf/dl-object.c in certain modified versions of the GNU C Library (aka glibc or libc6), including glibc-2.5-49.el5_5.6 and glibc-2.12-1.7.el6_0.3 in Red Hat Enterprise Linux, allow local users to gain privileges via a crafted dynamic shared object (DSO) in a subdirectory of the current working directory during execution of a (1) setuid or (2) setgid program that has $ORIGIN in (a) RPATH or (b) RUNPATH within the program itself or a referenced library. NOTE: this issue exists because of an incorrect fix for CVE-2010-3847.
VulDB is the best source for vulnerability data and more expert information about this specific topic.
Analysis
by VulDB Data Team • 12/28/2024
The vulnerability described in CVE-2011-0536 represents a critical privilege escalation flaw within the GNU C Library implementation of dynamic linking mechanisms. This issue specifically affects versions of glibc that were modified for Red Hat Enterprise Linux, including glibc-2.5-49.el5_5.6 and glibc-2.12-1.7.el6_0_3, where the library's handling of dynamic shared objects during program execution creates exploitable conditions. The vulnerability stems from improper path resolution behavior when setuid and setgid programs execute with $ORIGIN in their RPATH or RUNPATH settings, creating a dangerous search path scenario that malicious actors can leverage for unauthorized privilege elevation.
The technical flaw manifests in the elf/dl-object.c file where the dynamic linker fails to properly sanitize the search path when processing dynamic shared objects. When a setuid or setgid program executes, the dynamic linker attempts to resolve shared library dependencies but incorrectly prioritizes the current working directory in the search path. This behavior occurs specifically when the program or its referenced libraries contain $ORIGIN in either RPATH or RUNPATH entries, which should normally restrict library loading to specific locations. The vulnerability allows attackers to place malicious DSO files in subdirectories of the current working directory, which the dynamic linker will then load and execute with the elevated privileges of the setuid/setgid program, effectively bypassing the intended security boundaries.
The operational impact of this vulnerability is severe as it enables local privilege escalation attacks that can be executed by any user with access to the system. An attacker can craft a malicious shared object file and place it in a subdirectory where a setuid or setgid program is executed, causing the program to load and execute the malicious code with elevated privileges. This creates a persistent backdoor capability that can be exploited to gain root access or escalate privileges to other system users. The vulnerability is particularly dangerous because it leverages legitimate program execution paths and does not require special permissions beyond local access to the system, making it difficult to detect and prevent through traditional security controls.
This vulnerability aligns with CWE-427 Uncontrolled Search Path Element and CWE-428 Unquoted Search Path or Element, both of which address the fundamental issue of improper handling of library search paths. The flaw also maps to ATT&CK technique T1068, which covers the exploitation of privilege escalation vulnerabilities, and T1548.003, which covers abuse of legitimate credentials for privilege escalation. The incorrect fix for CVE-2010-3847 that introduced this vulnerability demonstrates how security patches can sometimes introduce new weaknesses when not thoroughly tested against all possible execution scenarios. Organizations should implement immediate mitigations including updating to patched versions of glibc, removing unnecessary setuid/setgid permissions from programs, and monitoring for suspicious library loading patterns in system logs. The vulnerability underscores the critical importance of proper library path handling in security-critical system components and the need for comprehensive testing of security patches in enterprise environments.