CVE-2002-0512 in Openlinux Server
Summary
by MITRE
startkde in KDE for Caldera OpenLinux 2.3 through 3.1.1 sets the LD_LIBRARY_PATH environment variable to include the current working directory, which could allow local users to gain privileges of other users running startkde via Trojan horse libraries.
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Analysis
by VulDB Data Team • 06/20/2024
The vulnerability identified as CVE-2002-0512 resides in the startkde script component of the KDE desktop environment, specifically affecting Caldera OpenLinux distributions version 2.3 through 3.1.1. This issue represents a classic privilege escalation vulnerability that exploits the insecure handling of environment variables during application initialization. The flaw occurs when the startkde script executes with elevated privileges, yet fails to properly sanitize the LD_LIBRARY_PATH environment variable, creating an exploitable condition that can be leveraged by local attackers to execute malicious code with higher privileges than intended.
The technical implementation of this vulnerability stems from the startkde script's practice of prepending the current working directory to the LD_LIBRARY_PATH variable. This design decision creates a security risk because it allows any user with write access to the current directory to place malicious shared libraries that will be loaded by the privileged startkde process. The vulnerability operates under the principle of insecure library loading, where the system loads libraries from predictable locations without proper validation of their integrity or authenticity. This behavior aligns with CWE-426, which describes the insecure use of a command that can be exploited through environment variable manipulation.
When a user runs startkde, the script executes with elevated privileges typically associated with the system's graphical environment initialization. However, due to the insecure LD_LIBRARY_PATH handling, any malicious library placed in the current working directory will be loaded before standard system libraries, potentially executing code with the privileges of the user running startkde. This creates a scenario where a local attacker can place a Trojan horse library in a directory they control, and when another user executes startkde from that directory, their session will load the malicious library instead of the legitimate system libraries, effectively hijacking the execution flow.
The operational impact of this vulnerability extends beyond simple privilege escalation, as it can be exploited to gain unauthorized access to system resources and potentially compromise the entire system. Attackers can leverage this weakness to execute arbitrary code with elevated privileges, potentially leading to complete system compromise. The vulnerability is particularly dangerous because it requires minimal privileges to exploit, as any user with write access to a directory containing startkde can potentially compromise the system. This weakness directly maps to several techniques described in the MITRE ATT&CK framework, specifically covering privilege escalation through environment variable manipulation and malicious library loading.
The recommended mitigations for this vulnerability include modifying the startkde script to avoid prepending the current working directory to LD_LIBRARY_PATH, instead using a secure path that does not include user-controllable directories. System administrators should also implement proper file permissions and access controls to limit write access to directories containing privileged executables. Additionally, the use of secure environment variable handling practices, such as explicitly setting LD_LIBRARY_PATH to known safe locations, can prevent this type of exploitation. Organizations should consider implementing mandatory access controls and privilege separation mechanisms to reduce the impact of such vulnerabilities in their environments, following security best practices outlined in various security frameworks including NIST guidelines for secure coding practices and environment variable security management.