CVE-2018-5783 in PoDoFo
Summary
by MITRE
In PoDoFo 0.9.5, there is an uncontrolled memory allocation in the PoDoFo::PdfVecObjects::Reserve function (base/PdfVecObjects.h). Remote attackers could leverage this vulnerability to cause a denial of service via a crafted pdf file.
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Analysis
by VulDB Data Team • 02/02/2023
The vulnerability identified as CVE-2018-5783 represents a critical memory allocation flaw within the PoDoFo PDF processing library version 0.9.5. This issue manifests in the PoDoFo::PdfVecObjects::Reserve function located in the base/PdfVecObjects.h file, where the library fails to properly control memory allocation requests. The flaw enables remote attackers to exploit malformed PDF documents that trigger excessive memory consumption during the object reservation process, potentially leading to system resource exhaustion and service disruption.
The technical nature of this vulnerability stems from inadequate input validation and memory management within the PDF parsing mechanism. When a maliciously crafted PDF file is processed by PoDoFo, the Reserve function attempts to allocate memory without proper bounds checking or limits on the requested allocation size. This uncontrolled memory allocation behavior creates a path for attackers to manipulate the library's memory consumption patterns through carefully constructed PDF payloads. The vulnerability operates at the core of PoDoFo's object management system, where it reserves space for PDF objects during document processing, making it a fundamental weakness in the library's memory handling architecture.
From an operational perspective, this vulnerability presents a significant denial of service risk that can affect any system utilizing PoDoFo 0.9.5 for PDF processing. Attackers can remotely trigger the vulnerability by delivering specially crafted PDF files to systems that process or render PDF documents, potentially causing memory exhaustion that leads to application crashes, system instability, or complete service unavailability. The impact extends beyond individual applications to potentially affect entire document processing pipelines, content management systems, and web applications that depend on PoDoFo for PDF handling capabilities. This vulnerability particularly affects environments where PDF files are automatically processed or where users can upload arbitrary PDF content without proper validation.
The mitigation strategies for CVE-2018-5783 primarily focus on immediate remediation through software updates and implementation of defensive measures. Organizations should prioritize upgrading to PoDoFo versions that contain fixed implementations of the PdfVecObjects::Reserve function, typically found in versions 0.9.6 and later. Additionally, implementing proper input validation and sanitization of PDF files before processing can serve as a temporary workaround while awaiting official patches. Network-level defenses such as PDF content filtering and sandboxing mechanisms can help reduce the attack surface by preventing malicious PDF files from reaching vulnerable applications. This vulnerability aligns with CWE-770, which addresses unauthorized resource consumption, and maps to ATT&CK technique T1499.004 for resource hijacking through denial of service attacks. System administrators should also consider implementing memory monitoring and alerting mechanisms to detect unusual memory consumption patterns that might indicate exploitation attempts.