CVE-2017-7380 in PoDoFo
Summary
by MITRE
The doc/PdfPage.cpp:614:20 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-2017-7380 resides within the PoDoFo library version 0.9.5, specifically in the doc/PdfPage.cpp file at line 614. This flaw represents a classic null pointer dereference issue that can be exploited by remote attackers through the careful crafting of malicious PDF documents. The PoDoFo library serves as a comprehensive C++ library for parsing and creating PDF files, making it a widely used component in various applications that handle PDF processing. When a malformed PDF document is processed by an application leveraging this vulnerable library, the software encounters a null pointer dereference during the page parsing routine, leading to an application crash and subsequent denial of service condition.
The technical implementation of this vulnerability stems from inadequate input validation within the PDF parsing logic. At the specific location in PdfPage.cpp, the code attempts to access a pointer that has not been properly initialized or validated, resulting in a null pointer dereference. This type of flaw falls under the Common Weakness Enumeration category CWE-476 which specifically addresses NULL Pointer Dereference conditions. The vulnerability demonstrates a fundamental lack of proper error handling and input sanitization, where the application fails to check if a pointer contains a valid memory address before attempting to dereference it. This particular code path in the PDF page processing module does not adequately handle edge cases or malformed data structures that might occur in crafted PDF files.
The operational impact of this vulnerability extends beyond simple application crashes, as it enables remote attackers to perform denial of service attacks against systems that rely on PoDoFo for PDF processing. Systems that process untrusted PDF content, such as web applications, email servers, document management systems, and PDF viewers, become vulnerable to this attack vector. The nature of the vulnerability means that any application using PoDoFo 0.9.5 and processing user-uploaded or externally sourced PDF files could be compromised, potentially affecting thousands of endpoints depending on the application ecosystem. This type of vulnerability aligns with the MITRE ATT&CK framework's T1499 technique category for network denial of service, as it specifically targets application availability through controlled input manipulation. The remote exploitation aspect means that attackers do not need physical access to the target system, making it particularly dangerous in networked environments where PDF processing occurs automatically.
Mitigation strategies for CVE-2017-7380 primarily focus on updating to a patched version of the PoDoFo library, as version 0.9.6 and later contain the necessary fixes for this vulnerability. Organizations should conduct thorough vulnerability assessments to identify all systems and applications that depend on PoDoFo, particularly those that process external PDF content. Implementing input validation and sanitization measures at the application level can provide additional defense-in-depth protection, though this approach is less reliable than patching the underlying library. Security teams should also consider implementing network segmentation and access controls to limit the potential impact of successful exploitation attempts. The vulnerability highlights the importance of maintaining up-to-date software libraries and implementing robust software supply chain security practices, as this issue demonstrates how a single flaw in a widely-used library can create widespread exposure across multiple applications and organizations.