CVE-2017-12376 in Antivirus Software
Summary
by MITRE
ClamAV AntiVirus software versions 0.99.2 and prior contain a vulnerability that could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition or potentially execute arbitrary code on an affected device. The vulnerability is due to improper input validation checking mechanisms when handling Portable Document Format (.pdf) files sent to an affected device. An unauthenticated, remote attacker could exploit this vulnerability by sending a crafted .pdf file to an affected device. This action could cause a handle_pdfname (in pdf.c) buffer overflow when ClamAV scans the malicious file, allowing the attacker to cause a DoS condition or potentially execute arbitrary code.
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Analysis
by VulDB Data Team • 02/02/2023
The vulnerability identified as CVE-2017-12376 represents a critical security flaw in ClamAV antivirus software affecting versions 0.99.2 and earlier. This weakness stems from inadequate input validation mechanisms within the PDF processing component of the antivirus engine, specifically in the handle_pdfname function located in the pdf.c source file. The flaw manifests when ClamAV encounters specially crafted PDF files during routine scanning operations, creating a scenario where maliciously formatted documents can trigger unexpected system behavior.
The technical implementation of this vulnerability involves a buffer overflow condition that occurs during PDF file processing. When ClamAV attempts to parse and analyze PDF documents, the handle_pdfname function fails to properly validate the length and structure of PDF name objects, allowing attackers to craft malicious input that exceeds the allocated buffer space. This buffer overflow creates opportunities for attackers to manipulate memory contents and potentially execute arbitrary code on the affected system. The vulnerability specifically targets the PDF parsing engine's handling of name objects, which are fundamental components used to identify and reference various elements within PDF documents.
From an operational perspective, this vulnerability presents significant risk to organizations relying on ClamAV for malware detection and prevention. The remote exploitation capability means attackers can trigger the vulnerability without requiring authentication or physical access to the target system. This makes the flaw particularly dangerous in networked environments where email attachments, web downloads, or file transfers could contain malicious PDF content. The potential for both denial of service and arbitrary code execution creates a dual threat that could disrupt operations while simultaneously providing attackers with persistent access to compromised systems. The vulnerability affects the core scanning functionality of ClamAV, potentially allowing attackers to bypass security controls or establish footholds within the network infrastructure.
Organizations should prioritize immediate patching of ClamAV installations to address this vulnerability, as the flaw affects widely deployed antivirus software across multiple platforms. The recommended mitigation strategy involves upgrading to ClamAV version 0.99.3 or later, which includes fixed input validation mechanisms for PDF processing. Network administrators should also consider implementing additional security measures such as PDF content filtering, sandboxing of suspicious documents, and enhanced monitoring of scanning activities for unusual patterns that might indicate exploitation attempts. This vulnerability aligns with CWE-121, which addresses stack-based buffer overflow conditions, and maps to ATT&CK technique T1059.007 for execution through PDF files, highlighting the need for comprehensive endpoint protection strategies that address both traditional malware and sophisticated attack vectors targeting security software itself.