CVE-2009-5064 in C Library
Summary
by MITRE
** DISPUTED ** ldd in the GNU C Library (aka glibc or libc6) 2.13 and earlier allows local users to gain privileges via a Trojan horse executable file linked with a modified loader that omits certain LD_TRACE_LOADED_OBJECTS checks. NOTE: the GNU C Library vendor states "This is just nonsense. There are a gazillion other ways to introduce code if people are downloading arbitrary binaries and install them in appropriate directories or set LD_LIBRARY_PATH etc."
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Analysis
by VulDB Data Team • 08/07/2024
The vulnerability described in CVE-2009-5064 relates to a potential privilege escalation issue within the GNU C Library (glibc) version 2.13 and earlier. This flaw exists in the ldd utility, which is used to display the shared libraries required by a program. The vulnerability arises from the interaction between ldd and the dynamic loader, specifically when dealing with executable files that have been modified to omit certain LD_TRACE_LOADED_OBJECTS checks. The core issue lies in how the system handles the loading process when these modified executables are executed, potentially allowing local attackers to exploit the system through carefully crafted Trojan horse binaries. This vulnerability represents a complex interaction between the dynamic linking mechanism and the privilege management aspects of the operating system.
The technical flaw stems from the insufficient validation of executable files when they are processed through the ldd utility. When an attacker creates a modified executable that omits specific LD_TRACE_LOADED_OBJECTS checks, the system's normal security mechanisms may not properly validate the integrity of the loaded libraries. This creates a potential attack vector where malicious code can be executed with elevated privileges, particularly when the modified loader bypasses standard security checks that would normally prevent such execution. The vulnerability is particularly concerning because it operates at the system library level, where the fundamental assumptions about program execution and library loading are compromised.
From an operational impact perspective, this vulnerability could enable local users to escalate their privileges on systems running affected versions of glibc. The attack requires the local user to have the ability to place malicious executables in locations where they can be executed, but once successful, the privilege escalation could allow attackers to gain elevated system access. The implications extend beyond simple local privilege escalation as the vulnerability could potentially be combined with other techniques to create more sophisticated attacks. The security implications are particularly severe in environments where users have the ability to install or modify executables in system directories, as this could provide a foothold for more extensive compromise.
The GNU C Library vendor has disputed the validity of this vulnerability, arguing that the reported issue is not a genuine security flaw but rather a misunderstanding of how the system operates. However, the vendor's response acknowledges that there are numerous other ways for attackers to introduce malicious code into systems, which suggests that while the specific CVE may be disputed, the broader category of vulnerabilities related to library loading and privilege escalation remains a legitimate concern. This vulnerability highlights the complex interplay between different system components and the challenges in defining precise security boundaries in complex software environments. The issue aligns with CWE-254 and other privilege escalation categories in the Common Weakness Enumeration taxonomy, as it involves improper handling of system privileges during program execution. The ATT&CK framework would classify this under privilege escalation techniques, specifically those involving dynamic loader manipulation and library injection methods, demonstrating how seemingly minor flaws in system utilities can create significant security risks when combined with other attack vectors.