CVE-2009-0755 in Poppler
Summary
by MITRE
The FormWidgetChoice::loadDefaults function in Poppler before 0.10.4 allows remote attackers to cause a denial of service (crash) via a PDF file with an invalid Form Opt entry.
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Analysis
by VulDB Data Team • 12/16/2024
The vulnerability described in CVE-2009-0755 represents a critical denial of service flaw within the Poppler PDF rendering library, specifically affecting versions prior to 0.10.4. This issue resides in the FormWidgetChoice::loadDefaults function which handles the processing of form elements within PDF documents. The flaw manifests when the library encounters a PDF file containing an invalid Form Opt entry, causing the application to crash during document processing. This vulnerability demonstrates a classic buffer over-read or improper input validation scenario that can be exploited by remote attackers to disrupt services without requiring authentication or specialized privileges.
The technical implementation of this vulnerability stems from inadequate validation of form field entries within PDF documents. When Poppler processes a PDF containing a malformed Form Opt entry, the FormWidgetChoice::loadDefaults function fails to properly validate the structure and content of the form options before attempting to load default values. This lack of input sanitization creates a condition where the function attempts to access memory locations or process data structures that do not conform to expected specifications. The vulnerability falls under the CWE-125 weakness category for out-of-bounds read conditions and aligns with ATT&CK technique T1499.004 for network denial of service. The flaw represents a failure in defensive programming practices where proper bounds checking and error handling mechanisms were not implemented to gracefully manage malformed input data.
The operational impact of this vulnerability extends beyond simple service disruption to potentially affect a wide range of applications that rely on Poppler for PDF processing. Systems utilizing Poppler for document rendering, web browsers, PDF viewers, and document management applications become vulnerable to this attack vector. Remote attackers can craft malicious PDF files containing invalid Form Opt entries and deliver them through various attack vectors including email attachments, web downloads, or compromised websites. When victims open these malicious documents, the application crashes and terminates unexpectedly, creating a denial of service condition that can be exploited at scale. The vulnerability is particularly concerning in environments where automated PDF processing occurs, as it can lead to cascading failures in document workflows and service availability.
Mitigation strategies for this vulnerability require immediate patching of affected Poppler installations to versions 0.10.4 or later where the issue has been resolved through proper input validation and error handling. Organizations should implement comprehensive vulnerability management processes to identify and remediate affected systems promptly. Additional defensive measures include implementing PDF file validation at network boundaries, deploying sandboxing techniques for PDF processing, and establishing monitoring for unusual application crash patterns. The fix typically involves adding proper bounds checking within the FormWidgetChoice::loadDefaults function to validate Form Opt entries before processing them, ensuring that malformed entries do not cause the application to crash. Security teams should also consider implementing automated patch management systems and regular security assessments to prevent similar vulnerabilities from emerging in other components of their PDF processing infrastructure.