CVE-2017-12378 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 on an affected device. The vulnerability is due to improper input validation checking mechanisms of .tar (Tape Archive) files sent to an affected device. A successful exploit could cause a checksum buffer over-read condition when ClamAV scans the malicious .tar file, potentially allowing the attacker to cause a DoS condition on the affected device.
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Analysis
by VulDB Data Team • 02/02/2023
The vulnerability identified as CVE-2017-12378 represents a critical denial of service weakness in ClamAV antivirus software affecting versions 0.99.2 and earlier. This flaw resides within the software's handling of .tar archive files, specifically during the scanning process where the antivirus engine attempts to validate and process archive contents. The issue stems from inadequate input validation mechanisms that fail to properly sanitize or verify the structure of incoming tar files before processing them. When ClamAV encounters a maliciously crafted tar file, the software's checksum validation routine becomes susceptible to buffer over-read conditions, which can trigger unexpected program behavior and system instability.
The technical exploitation of this vulnerability occurs through the manipulation of tar file structures that cause the checksum calculation routine to access memory beyond the allocated buffer boundaries. This buffer over-read condition manifests as a memory corruption issue that can lead to application crashes, process termination, or complete system hang conditions. The vulnerability is particularly concerning because it requires no authentication credentials to exploit, making it accessible to any remote attacker who can deliver a malicious tar file to a targeted system. The flaw operates at the parsing layer of the antivirus engine where archive files are decompressed and analyzed for potential threats, creating a direct pathway for remote attackers to disrupt system availability.
From an operational standpoint, this vulnerability presents significant risk to organizations relying on ClamAV for endpoint protection, as it can be leveraged to create widespread service disruption without requiring sophisticated attack vectors or privileged access. The impact extends beyond individual system compromise to potentially affect entire network infrastructures where ClamAV is deployed as a centralized scanning solution. Attackers could exploit this weakness to target email servers, file servers, or other systems that process tar archives, leading to cascading denial of service conditions that could persist until the affected systems are manually restarted or the vulnerable ClamAV version is updated. The vulnerability's remote exploitability means that organizations cannot rely solely on network segmentation or access controls to prevent exploitation, as the attack can be initiated from external sources without prior system compromise.
Organizations should prioritize immediate remediation through updating to ClamAV version 0.99.3 or later, which contains the necessary patches to address the buffer over-read condition in tar file processing. Additional mitigations include implementing network-based filtering to block suspicious tar file attachments, deploying intrusion detection systems that can identify potential exploitation attempts, and establishing monitoring procedures to detect service disruptions that may indicate exploitation. The vulnerability aligns with CWE-121, which describes buffer overflow conditions in heap-based memory management, and represents a classic example of improper input validation that enables denial of service attacks. From an ATT&CK framework perspective, this vulnerability maps to techniques involving service disruption and system resource exhaustion, potentially enabling broader attack chains where initial denial of service conditions are used to facilitate additional compromise attempts. Organizations should also consider implementing multiple layers of defense including regular vulnerability assessments, network traffic analysis, and maintaining up-to-date threat intelligence to identify potential exploitation attempts targeting this or similar vulnerabilities in their security infrastructure.