CVE-2008-5298 in chm2pdf
Summary
by MITRE
chm2pdf 0.9 uses temporary files in directories with fixed names, which allows local users to cause a denial of service (chm2pdf failure) of other users by creating those directories ahead of time.
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Analysis
by VulDB Data Team • 04/09/2025
The vulnerability identified as CVE-2008-5298 affects chm2pdf version 0.9, a tool designed to convert Microsoft Compiled HTML Help files into PDF documents. This issue stems from the application's improper handling of temporary file creation during the conversion process, creating a predictable and exploitable weakness in the software's security model. The flaw manifests when the application attempts to create temporary files in directories with predetermined names, which can be manipulated by malicious local users to disrupt normal operations.
The technical implementation of this vulnerability exploits a fundamental flaw in temporary file management practices, specifically violating the principle of secure temporary file creation as outlined in various security frameworks. When chm2pdf executes, it creates temporary directories with fixed names such as tmpdir or similar predictable patterns, which are then used for intermediate processing files. Local attackers can pre-create these directories with malicious intent, causing the application to fail when it attempts to write to these locations. This behavior represents a classic case of insecure temporary file handling that can be categorized under CWE-377, which addresses insecure temporary file creation practices.
The operational impact of this vulnerability extends beyond simple denial of service, as it can effectively prevent legitimate users from performing chm2pdf conversions. When an attacker creates directories with the same names that chm2pdf expects to use, the conversion process fails because the application cannot create the necessary temporary files in the expected locations. This creates a cascading effect where users attempting to convert chm files experience complete failure of the tool, potentially disrupting workflows in environments where chm2pdf is a critical component for documentation processing. The vulnerability is particularly concerning in multi-user environments where one user could deliberately disrupt another user's ability to convert files.
From a cybersecurity perspective, this vulnerability aligns with ATT&CK technique T1499.004, which covers "Utilities: File Deletion" and related denial of service mechanisms. The attack vector leverages local privilege escalation through file system manipulation rather than network-based attacks, making it particularly insidious as it requires no external network access. The vulnerability demonstrates poor security hygiene in the software's design and implementation, as it fails to properly validate or sanitize temporary file locations before attempting to create them. This weakness is further compounded by the lack of proper error handling and file system permission checks that would normally prevent such conflicts from occurring. The issue represents a fundamental failure in the software's security architecture and underscores the importance of following secure coding practices, particularly around temporary file management and resource allocation. Organizations using chm2pdf should implement immediate mitigations including updating to patched versions or implementing proper temporary file handling mechanisms that randomize directory names or use system-standard temporary locations with appropriate access controls.