CVE-2009-1144 in Xpdf
Summary
by MITRE
Untrusted search path vulnerability in the Gentoo package of Xpdf before 3.02-r2 allows local users to gain privileges via a Trojan horse xpdfrc file in the current working directory, related to an unset SYSTEM_XPDFRC macro in a Gentoo build process that uses the poppler library.
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Analysis
by VulDB Data Team • 08/09/2021
The vulnerability described in CVE-2009-1144 represents a classic untrusted search path issue that emerged within the Gentoo package distribution of Xpdf software before version 3.02-r2. This flaw stems from the improper handling of configuration file loading during the software's initialization process, specifically when the SYSTEM_XPDFRC macro remains unset during the Gentoo build procedure. The vulnerability creates a privilege escalation vector that allows local attackers to execute malicious code with elevated privileges by placing a specially crafted xpdfrc file in the current working directory from which the application is launched.
The technical root cause of this vulnerability lies in the software's failure to properly validate or sanitize the search path used to locate configuration files. When the SYSTEM_XPDFRC macro is not explicitly set during compilation, the Xpdf application defaults to searching for configuration files in predictable locations including the current working directory. This behavior violates the principle of least privilege and creates a directory traversal attack surface where malicious actors can place a Trojan horse xpdfrc file that will be loaded and executed with the privileges of the targeted user. The vulnerability is particularly dangerous because it leverages the normal operation of the application rather than requiring exploitation of a separate bug, making it more reliable and easier to execute.
The operational impact of this vulnerability extends beyond simple privilege escalation to encompass potential system compromise and data exfiltration. When a local user places a malicious xpdfrc file in a directory where Xpdf is executed, the configuration file can contain commands that execute arbitrary code, modify system settings, or redirect application behavior. This creates a persistent threat vector that can be exploited across multiple application launches and potentially across different user sessions. The vulnerability affects not only individual users but also system administrators who might inadvertently execute Xpdf from compromised directories, making it a significant concern for enterprise environments where multiple users share common file systems. The use of the poppler library in the Gentoo build process compounds the issue by introducing additional attack surface through the library's own configuration handling mechanisms.
Mitigation strategies for CVE-2009-1144 focus on both immediate patching and long-term architectural improvements to prevent similar vulnerabilities. The most direct solution involves updating to Xpdf version 3.02-r2 or later, which properly addresses the unset SYSTEM_XPDFRC macro issue by ensuring that system-wide configuration paths are prioritized over user-controlled directories. System administrators should also implement directory permission controls to restrict write access to locations where Xpdf or similar applications are executed, particularly in shared or multi-user environments. The vulnerability aligns with CWE-276, which describes improper file permissions, and CWE-426, which addresses the execution of untrusted code, while also mapping to ATT&CK technique T1068, which covers local privilege escalation through untrusted search paths. Organizations should conduct regular audits of their software packages to identify similar untrusted search path vulnerabilities in other applications, particularly those using build systems that might not properly define system configuration paths. Additionally, implementing application whitelisting and sandboxing mechanisms can provide defense-in-depth protection against exploitation attempts, while monitoring for suspicious file creation patterns in directories where executables are commonly launched can help detect potential exploitation attempts.