CVE-2017-6849 in PoDoFo
Summary
by MITRE
The PoDoFo::PdfColorGray::~PdfColorGray function in PdfColor.cpp in PoDoFo 0.9.4 allows remote attackers to cause a denial of service (NULL pointer dereference) via a crafted file.
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Analysis
by VulDB Data Team • 10/09/2024
The vulnerability identified as CVE-2017-6849 represents a critical denial of service flaw within the PoDoFo PDF processing library version 0.9.4. This issue manifests in the PdfColorGray destructor function located in the PdfColor.cpp source file, where a NULL pointer dereference condition can be triggered by maliciously crafted PDF files. The PoDoFo library serves as a comprehensive PDF manipulation framework widely utilized in various applications for PDF document creation, modification, and processing, making this vulnerability particularly concerning from a security perspective.
The technical exploitation of this vulnerability occurs when an attacker crafts a specially formatted PDF document that contains malformed grayscale color data. When the PoDoFo library attempts to process this malicious file and subsequently calls the PdfColorGray destructor, the code fails to properly validate pointer references before dereferencing them. This NULL pointer dereference results in an application crash, effectively causing a denial of service condition that prevents legitimate users from accessing or processing PDF documents through applications built on top of the PoDoFo library. The vulnerability stems from inadequate input validation and error handling within the color processing component of the PDF parser.
From an operational standpoint, this vulnerability poses significant risks to organizations relying on PoDoFo-based applications for document processing workflows. The remote nature of the attack means that malicious actors can exploit this flaw without requiring local access to target systems, making it particularly dangerous in web-based environments where PDF files are frequently processed. Applications such as document management systems, automated PDF processing pipelines, and web applications that utilize PoDoFo for PDF generation or manipulation become vulnerable to this type of denial of service attack. The impact extends beyond simple service disruption to potentially affecting business operations that depend on continuous PDF processing capabilities.
The vulnerability aligns with CWE-476 which specifically addresses NULL pointer dereference conditions in software implementations. From an ATT&CK framework perspective, this flaw represents a denial of service technique that can be categorized under the T1499.004 sub-technique for network denial of service, where adversaries leverage application-level vulnerabilities to disrupt services. The weakness exists in the input validation and error handling mechanisms of the PDF color processing module, highlighting the importance of robust defensive programming practices in security-critical components. Organizations should prioritize updating to patched versions of PoDoFo, implementing proper input sanitization measures, and deploying intrusion detection systems to monitor for exploitation attempts. Additionally, application developers should consider implementing proper exception handling and null pointer checks in their code to prevent similar issues from occurring in other components of their software stack.