CVE-2017-6843 in PoDoFo
Summary
by MITRE
Heap-based buffer overflow in the PoDoFo::PdfVariant::DelayedLoad function in PdfVariant.h in PoDoFo 0.9.4 allows remote attackers to have unspecified impact via a crafted file.
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Analysis
by VulDB Data Team • 09/09/2020
The heap-based buffer overflow vulnerability in PoDoFo 0.9.4 represents a critical security flaw within the PDF processing library that can be exploited by remote attackers to execute arbitrary code or cause system instability. This vulnerability specifically affects the PoDoFo::PdfVariant::DelayedLoad function located in the PdfVariant.h header file, which is responsible for handling delayed loading of PDF variant data structures. The flaw occurs when the library processes malformed PDF files that contain specially crafted data structures designed to trigger the buffer overflow condition during the parsing process.
The technical implementation of this vulnerability stems from inadequate input validation and memory management within the PDF variant parsing mechanism. When PoDoFo encounters a PDF file with maliciously constructed variant data, the DelayedLoad function fails to properly bounds-check the incoming data before copying it into heap-allocated buffers. This allows attackers to overflow the allocated memory space and potentially overwrite adjacent memory regions, leading to arbitrary code execution or denial of service conditions. The vulnerability is particularly dangerous because it can be triggered through remote file processing, making it exploitable via web applications or email attachments that process PDF documents.
The operational impact of CVE-2017-6843 extends beyond simple privilege escalation or system compromise, as it affects any application or service that relies on PoDoFo 0.9.4 for PDF processing capabilities. Attackers can leverage this vulnerability to execute malicious code on systems running vulnerable applications, potentially leading to complete system compromise, data exfiltration, or lateral movement within network environments. The unspecified impact mentioned in the CVE description indicates that the vulnerability could enable various attack vectors depending on the execution context and target system configuration. This vulnerability is particularly concerning for web applications, document management systems, and email security solutions that process untrusted PDF content.
Security professionals should prioritize patching affected systems immediately, as PoDoFo 0.9.4 has been superseded by newer versions that address this heap overflow vulnerability through improved input validation and memory management practices. The mitigation strategy should include updating to PoDoFo version 0.9.5 or later, implementing strict input validation for PDF files, and deploying network-based intrusion detection systems to monitor for exploitation attempts. Additionally, organizations should consider implementing sandboxing mechanisms and privilege separation when processing PDF documents to limit the potential impact of successful exploitation attempts. This vulnerability aligns with CWE-121 heap-based buffer overflow categories and represents a significant concern for attackers using techniques from the attack pattern taxonomy that target memory corruption vulnerabilities in document processing libraries.