CVE-2018-11255 in PoDoFo
Summary
by MITRE
An issue was discovered in PoDoFo 0.9.5. The function PdfPage::GetPageNumber() in PdfPage.cpp 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 • 03/14/2023
The vulnerability identified as CVE-2018-11255 represents a critical denial of service weakness within the PoDoFo library version 0.9.5. This issue stems from improper input validation within the PdfPage::GetPageNumber() function located in the PdfPage.cpp source file. The flaw manifests when the library processes maliciously crafted PDF documents that contain malformed page references or corrupted metadata structures. Attackers can exploit this vulnerability by constructing a specially designed PDF file that triggers a NULL pointer dereference during the page number retrieval operation, leading to an application crash and complete service disruption.
The technical nature of this vulnerability aligns with CWE-476 which describes NULL pointer dereference conditions in software systems. This weakness occurs because the PdfPage::GetPageNumber() function fails to properly validate whether the page object or its associated metadata pointers are valid before attempting to access them. When processing a crafted PDF document, the function encounters a NULL reference that has not been adequately handled, resulting in an unhandled exception that terminates the application process. The vulnerability demonstrates poor defensive programming practices where the code assumes certain data structures will always contain valid references without proper null checks or error handling mechanisms.
From an operational impact perspective, this vulnerability creates significant risks for any system or application that relies on PoDoFo for PDF processing capabilities. The denial of service condition affects availability of services, potentially allowing attackers to disrupt legitimate PDF processing workflows in document management systems, web applications, or content management platforms. The vulnerability is particularly concerning because it can be exploited remotely through the processing of malicious PDF files, making it applicable to web-based PDF viewers, document conversion services, and automated document processing systems. Organizations using PoDoFo in production environments face the risk of service interruptions that could impact business operations, document workflows, and user access to critical PDF-based applications.
The exploitation of this vulnerability follows patterns consistent with attack techniques documented in the MITRE ATT&CK framework under the T1499 category for network denial of service attacks. The attack surface is broad as PoDoFo is widely used in various applications including web browsers, document viewers, and server-side PDF processing systems. Security professionals should note that the vulnerability is not limited to specific use cases but affects any implementation that utilizes the affected function within the library. Organizations should prioritize patching or mitigating this vulnerability as it represents a straightforward path to service disruption that requires minimal technical expertise to execute. The remediation approach should focus on updating to a patched version of PoDoFo or implementing input validation controls that prevent malformed PDF documents from reaching the vulnerable function, thereby protecting against both immediate exploitation and potential future variants of similar vulnerabilities.