CVE-2000-1163 in Ghostscript
Summary
by MITRE
ghostscript before 5.10-16 uses an empty LD_RUN_PATH environmental variable to find libraries in the current directory, which could allow local users to execute commands as other users by placing a Trojan horse library into a directory from which another user executes ghostscript.
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Analysis
by VulDB Data Team • 05/28/2018
The vulnerability described in CVE-2000-1163 represents a classic path traversal and privilege escalation issue within the ghostscript document processing software. This flaw existed in ghostscript versions prior to 5.10-16 and exploited a fundamental security oversight in how the software handled dynamic library loading. The vulnerability specifically leveraged the LD_RUN_PATH environmental variable, which is used by the dynamic linker to determine where to search for shared libraries during program execution. When this variable was empty or unset, ghostscript would fall back to searching the current working directory for required libraries, creating a dangerous condition where malicious actors could manipulate the library loading process.
The technical exploitation of this vulnerability occurs through a carefully crafted Trojan horse library placement attack. An attacker with access to a directory where another user might execute ghostscript could place a malicious shared library file with the same name as a legitimate library that ghostscript expects to load. When the victim user executes ghostscript from that directory, the dynamic linker would load the attacker-controlled library instead of the legitimate one, effectively allowing the attacker to execute arbitrary code with the privileges of the victim user. This represents a privilege escalation vulnerability that can be particularly dangerous in multi-user environments where users might execute ghostscript from shared directories or temporary locations.
The operational impact of this vulnerability extends beyond simple code execution, as it can enable attackers to gain unauthorized access to systems and potentially escalate privileges to higher levels. The vulnerability is particularly concerning because it does not require network access or complex exploitation techniques, making it accessible to attackers with minimal privileges who simply need write access to directories where ghostscript might be executed. This type of vulnerability aligns with CWE-426, which describes the weakness of untrusted search path, and can be mapped to ATT&CK technique T1068, which covers the exploitation of privilege escalation vulnerabilities. The attack vector specifically targets the dynamic linking mechanism and demonstrates how improper handling of environmental variables can create security holes in system software.
The recommended mitigations for this vulnerability include updating to ghostscript version 5.10-16 or later, which properly addresses the empty LD_RUN_PATH issue by implementing secure library loading practices. System administrators should also implement strict directory permissions and audit access to directories where ghostscript might be executed, particularly shared or temporary directories. Additionally, implementing proper security configurations that prevent the use of empty LD_RUN_PATH variables and enforcing secure coding practices for dynamic library loading can help prevent similar issues. Organizations should also consider implementing monitoring and alerting for unauthorized library file modifications in directories where critical system tools execute, as this vulnerability can be used to establish persistent access to systems through privilege escalation attacks.