CVE-2018-8001 in PoDoFo
Summary
by MITRE
In PoDoFo 0.9.5, there exists a heap-based buffer over-read vulnerability in UnescapeName() in PdfName.cpp. Remote attackers could leverage this vulnerability to cause a denial-of-service or possibly unspecified other impact via a crafted pdf file.
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Analysis
by VulDB Data Team • 01/12/2020
The vulnerability identified as CVE-2018-8001 represents a critical heap-based buffer over-read flaw within the PoDoFo library version 0.9.5. This issue manifests specifically within the UnescapeName() function located in the PdfName.cpp source file, demonstrating a classic memory safety vulnerability that can be exploited through maliciously crafted pdf documents. The PoDoFo library serves as a comprehensive pdf processing toolkit widely utilized in various applications for pdf generation, manipulation, and parsing operations across multiple platforms and systems.
The technical exploitation of this vulnerability occurs when the UnescapeName() function processes malformed pdf name objects that contain specially crafted data structures. During the unescaping process, the function fails to properly validate input boundaries, leading to a situation where memory reads extend beyond the allocated buffer limits. This over-read condition can result in the function accessing adjacent memory locations that may contain sensitive data, corrupted information, or potentially executable code segments. The vulnerability's classification as heap-based indicates that the memory allocation occurs on the heap rather than the stack, making the exploitation scenario more complex but equally dangerous due to the potential for information disclosure or system instability.
From an operational perspective, this vulnerability presents significant risks to organizations relying on PoDoFo for pdf processing tasks, particularly in environments where pdf files are received from untrusted sources. Remote attackers can leverage this flaw by preparing specially crafted pdf documents that trigger the vulnerable code path during parsing operations. The impact of exploitation can range from simple denial-of-service conditions that crash applications to more severe scenarios where the over-read might expose sensitive memory contents or potentially enable further exploitation techniques. The vulnerability's remote attack surface means that systems processing pdf files from the internet or untrusted networks are at risk without proper mitigation measures.
The vulnerability aligns with CWE-125, which describes "Out-of-bounds Read" conditions that occur when software reads data past the end of a valid buffer. This weakness specifically manifests in the context of memory safety within pdf parsing libraries and demonstrates how seemingly benign input processing can lead to critical security implications. Organizations utilizing PoDoFo should consider implementing the mitigation strategies recommended by the ATT&CK framework for defensive measures against buffer overflow vulnerabilities. These include input validation, memory safety improvements, and application sandboxing techniques to limit the potential impact of such vulnerabilities. The recommended remediation involves upgrading to PoDoFo version 0.9.6 or later, which includes patches addressing this specific heap over-read condition, along with implementing additional security controls such as pdf file validation, sandboxed processing environments, and regular security assessments of pdf handling components within applications.