CVE-2017-8053 in PoDoFo
Summary
by MITRE
PoDoFo 0.9.5 allows denial of service (infinite recursion and stack consumption) via a crafted PDF file in PoDoFo::PdfParser::ReadDocumentStructure (PdfParser.cpp).
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Analysis
by VulDB Data Team • 08/24/2024
The vulnerability identified as CVE-2017-8053 represents a critical denial of service flaw within the PoDoFo library version 0.9.5, specifically affecting the PdfParser::ReadDocumentStructure function in PdfParser.cpp. This issue arises from inadequate input validation and error handling mechanisms within the PDF parsing component, creating a scenario where maliciously crafted PDF files can trigger infinite recursion patterns. The flaw demonstrates characteristics consistent with CWE-674, which describes uncontrolled recursion in software systems, where recursive functions lack proper termination conditions or adequate stack depth management. Attackers can exploit this vulnerability by constructing PDF documents that contain malformed structures designed to cause the parser to enter infinite recursive loops during document structure analysis.
The technical implementation of this vulnerability occurs when the PdfParser::ReadDocumentStructure function processes specially crafted PDF files that contain recursive references or malformed object structures. The parser fails to implement proper safeguards against excessive nesting levels or recursive object references, allowing an attacker to craft PDF documents that cause the parsing routine to repeatedly call itself without reaching a termination condition. This results in rapid stack consumption and eventually leads to application crash or complete system denial of service. The vulnerability specifically targets the document structure reading functionality, which is fundamental to PDF processing operations, making it particularly impactful for applications that rely on PoDoFo for PDF manipulation and parsing tasks. The recursive nature of the flaw means that even a single malicious PDF file can cause the entire application to become unresponsive, as the stack frames continue to accumulate until system resources are exhausted.
From an operational perspective, this vulnerability poses significant risks to organizations that utilize PoDoFo in their document processing pipelines, particularly in environments where PDF files are received from untrusted sources. The denial of service impact extends beyond simple application crashes to potentially disrupt entire document management systems, content delivery networks, or automated processing workflows that depend on PDF handling capabilities. The vulnerability can be exploited through various attack vectors including web applications that process user-uploaded PDF files, email systems that scan PDF attachments, or document management platforms that automatically parse and index PDF content. According to ATT&CK framework category T1499, this vulnerability aligns with resource exhaustion techniques that target application stability and availability, potentially enabling broader attack campaigns where multiple systems are compromised through service disruption.
Mitigation strategies for CVE-2017-8053 should prioritize immediate patching of affected PoDoFo library versions to address the recursive parsing flaw. Organizations should implement input validation measures that establish maximum nesting levels and recursion depth limits for PDF document structures, preventing malicious files from triggering infinite loops during parsing operations. Additionally, defensive programming practices should be enforced including stack depth monitoring, timeout mechanisms for parsing operations, and comprehensive error handling that can detect and terminate recursive patterns before system resources are exhausted. Network-level defenses such as PDF scanning appliances and content filtering systems can provide additional layers of protection by identifying and quarantining suspicious PDF files before they reach vulnerable applications. The vulnerability also underscores the importance of proper software supply chain security practices, including regular vulnerability assessments of third-party libraries and implementation of automated patch management processes to ensure timely remediation of known security flaws.