CVE-2020-3341 in ClamAV
Summary
by MITRE
A vulnerability in the PDF archive parsing module in Clam AntiVirus (ClamAV) Software versions 0.101 - 0.102.2 could allow an unauthenticated, remote attacker to cause a denial of service condition on an affected device. The vulnerability is due to a stack buffer overflow read. An attacker could exploit this vulnerability by sending a crafted PDF file to an affected device. An exploit could allow the attacker to cause the ClamAV scanning process crash, resulting in a denial of service condition.
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Analysis
by VulDB Data Team • 10/18/2020
The vulnerability identified as CVE-2020-3341 represents a critical stack buffer overflow flaw within the PDF archive parsing functionality of Clam AntiVirus software. This security weakness specifically affects ClamAV versions 0.101 through 0.102.2, creating an exploitable condition that enables remote attackers to disrupt system operations without requiring authentication. The vulnerability stems from improper bounds checking during the parsing of PDF archive structures, where the software fails to adequately validate input data before processing it in memory. This fundamental flaw in input validation creates a pathway for malicious actors to craft specially formatted PDF files that trigger the buffer overflow condition.
The technical implementation of this vulnerability manifests as a stack buffer overflow read condition that occurs when ClamAV attempts to parse malformed PDF archive files. When processing these crafted inputs, the software's PDF parsing module does not properly constrain memory access patterns, allowing an attacker to overwrite adjacent stack memory locations. This overflow condition specifically targets the software's parsing routines that handle PDF archive structures, where insufficient boundary checks permit data to be read beyond allocated memory buffers. The flaw operates through a classic buffer overrun scenario where attacker-controlled data exceeds the intended buffer capacity, causing unpredictable behavior in the scanning process.
From an operational perspective, this vulnerability creates a significant denial of service risk for systems relying on ClamAV for malware detection and prevention. The exploitation of CVE-2020-3341 results in immediate system disruption through complete process crashes of the ClamAV scanning service, effectively rendering the anti-virus protection unavailable during the time required for system recovery. Organizations utilizing affected ClamAV versions face potential operational downtime, increased incident response requirements, and compromised security posture as the system becomes temporarily unable to perform its core malware scanning functions. The remote nature of the attack means that systems can be compromised without physical access or user interaction, making it particularly dangerous for networked environments.
The security implications extend beyond simple service disruption to encompass broader operational resilience concerns for enterprise security infrastructure. This vulnerability directly impacts the availability component of the CIA triad, specifically targeting the availability of anti-virus scanning capabilities that organizations depend upon for malware detection. The flaw aligns with CWE-121 Stack-based Buffer Overflow, which categorizes buffer overflows occurring in stack memory regions as particularly dangerous due to their potential for arbitrary code execution and system compromise. Organizations should consider this vulnerability in their broader threat modeling and incident response planning, as it represents a vector for attackers to disable critical security controls. Mitigation strategies should include immediate version upgrades to patched ClamAV releases, network segmentation to limit exposure, and enhanced monitoring for suspicious PDF file handling activities. The ATT&CK framework categorizes this as a Denial of Service technique under the system service execution category, highlighting the strategic impact on organizational security operations and the need for robust patch management processes to prevent exploitation.