CVE-2002-0169 in DocBook Stylesheets
Summary
by MITRE
The default stylesheet for DocBook on Red Hat Linux 6.2 through 7.2 is installed with an insecure option enabled, which could allow users to overwrite files outside of the current directory from an untrusted document by using a full pathname as an element identifier.
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Analysis
by VulDB Data Team • 04/12/2019
The vulnerability described in CVE-2002-0169 represents a significant security flaw in the DocBook processing framework on Red Hat Linux systems spanning versions 6.2 through 7.2. This issue stems from the default stylesheet configuration that permits arbitrary file overwrites when processing untrusted XML documents containing full pathnames as element identifiers. The vulnerability operates at the intersection of XML processing security and file system access control, creating a scenario where maliciously crafted documents can exploit the stylesheet's handling of pathnames to write files beyond the intended directory structure. This represents a classic path traversal vulnerability that leverages the document processing pipeline to bypass normal file system security boundaries.
The technical implementation of this flaw involves the DocBook stylesheet's interpretation of element identifiers that contain absolute pathnames. When an untrusted XML document is processed through the vulnerable DocBook system, the stylesheet incorrectly handles these full pathnames, treating them as valid file paths rather than as identifiers within the document structure. This misinterpretation allows attackers to specify arbitrary file locations for output operations, effectively bypassing the normal sandboxing mechanisms that should protect the file system from unauthorized access. The vulnerability is particularly dangerous because it operates within the document processing pipeline, where input validation is often minimal or absent, and the processing occurs with elevated privileges typically associated with system-level document rendering tools.
The operational impact of this vulnerability extends beyond simple file overwrites to encompass potential system compromise and data integrity violations. An attacker could leverage this flaw to overwrite critical system files, configuration documents, or user data, potentially leading to privilege escalation or service disruption. The vulnerability affects any application or service that relies on the default DocBook stylesheet for processing XML documents, making it particularly concerning in environments where untrusted input is processed, such as web applications, document management systems, or automated build processes. The attack vector is relatively straightforward requiring only the creation of a malicious XML document containing full pathnames in element identifiers, which can be easily constructed and deployed by threat actors with minimal technical expertise.
Organizations affected by this vulnerability should immediately implement mitigations including updating to patched versions of the DocBook tools, modifying stylesheet configurations to disable insecure options, and implementing strict input validation for all XML processing pipelines. The vulnerability aligns with CWE-22 Path Traversal and CWE-73 Improper Neutralization of Special Elements in Output Used by a Downstream Component, highlighting the need for proper input sanitization and output handling. From an ATT&CK perspective, this vulnerability maps to T1059 Command and Scripting Interpreter and T1566 Phishing, as attackers can use this flaw to execute malicious payloads through document processing or deliver phishing content that exploits the vulnerability. System administrators should also consider implementing network segmentation and access controls to limit the potential impact of exploitation, while monitoring for suspicious file modification patterns that might indicate exploitation attempts. The remediation process requires careful attention to ensure that updated configurations maintain the intended functionality of document processing while eliminating the security risk associated with insecure path handling.