CVE-2017-7381 in PoDoFo
Summary
by MITRE
The doc/PdfPage.cpp:609:23 code in PoDoFo 0.9.5 allows remote attackers to cause a denial of service (NULL pointer dereference and application crash) via a crafted PDF document.
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Analysis
by VulDB Data Team • 08/25/2020
The vulnerability identified as CVE-2017-7381 resides within the PoDoFo library version 0.9.5, specifically in the doc/PdfPage.cpp file at line 609. This flaw represents a critical denial of service vulnerability that can be exploited by remote attackers through the manipulation of PDF documents. The issue manifests when the application processes a specially crafted PDF file that triggers a NULL pointer dereference condition, ultimately leading to application crash and system instability. This vulnerability affects any software implementation that relies on PoDoFo for PDF processing and rendering capabilities.
The technical root cause of this vulnerability stems from inadequate input validation within the PDF page processing module of the PoDoFo library. When parsing PDF documents, the code fails to properly check for null references before attempting to dereference pointers, creating a scenario where maliciously constructed PDF files can force the application into an undefined state. This NULL pointer dereference occurs during the handling of specific PDF page elements, particularly when processing complex page structures or malformed data within the PDF file. The vulnerability is classified under CWE-476 as a NULL Pointer Dereference, which is a well-known software weakness that has been consistently identified across numerous security assessments and penetration testing engagements.
The operational impact of this vulnerability extends beyond simple service disruption, as it can be leveraged by attackers to perform systematic denial of service attacks against systems that process PDF documents. Any application utilizing PoDoFo for PDF generation, manipulation, or rendering becomes susceptible to this attack vector, including web applications, document management systems, and email servers that handle PDF attachments. The vulnerability's remote exploitation capability means that attackers can trigger the crash without requiring local access to the target system, making it particularly dangerous in networked environments. This type of vulnerability aligns with ATT&CK technique T1499.004 for Network Denial of Service, where adversaries can disrupt services by exploiting software weaknesses.
Mitigation strategies for CVE-2017-7381 primarily involve upgrading to a patched version of the PoDoFo library, as version 0.9.6 and later contain the necessary code modifications to properly handle NULL pointer conditions. Organizations should implement comprehensive patch management procedures to ensure all systems utilizing PoDoFo are updated promptly. Additionally, deploying input validation mechanisms and implementing sandboxing techniques for PDF processing can provide defense-in-depth measures. Network administrators should consider implementing PDF content filtering and scanning solutions to detect and block potentially malicious PDF files before they reach end-user systems. The vulnerability also underscores the importance of proper software security testing and code review practices, particularly for libraries handling untrusted input data, as highlighted in industry standards such as the OWASP Top Ten and NIST SP 800-53 security controls.