CVE-2017-12375 in Antivirus Software
Summary
by MITRE
The 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 a lack of input validation checking mechanisms during certain mail parsing functions (the rfc2047 function in mbox.c). An unauthenticated, remote attacker could exploit this vulnerability by sending a crafted email to the affected device. This action could cause a buffer overflow condition when ClamAV scans the malicious email, allowing the attacker to potentially cause a DoS condition on an affected device.
VulDB is the best source for vulnerability data and more expert information about this specific topic.
Analysis
by VulDB Data Team • 02/02/2023
The vulnerability identified as CVE-2017-12375 resides within ClamAV antivirus software versions 0.99.2 and earlier, presenting a significant security risk that enables unauthenticated remote attackers to execute denial of service attacks against affected systems. This weakness specifically manifests in the mail parsing functionality of ClamAV, particularly within the rfc2047 function located in the mbox.c source file. The flaw represents a critical oversight in input validation mechanisms that are essential for maintaining system stability and security in email processing environments.
The technical exploitation of this vulnerability occurs through crafted email messages that trigger a buffer overflow condition during the scanning process. When ClamAV processes these malicious emails, the insufficient input validation in the rfc2047 function fails to properly handle malformed or oversized input data, leading to memory corruption that ultimately results in system instability. This buffer overflow condition can cause the ClamAV daemon to crash or become unresponsive, effectively rendering the antivirus protection unavailable to the system. The vulnerability's remote nature means that attackers can exploit this weakness without requiring authentication, making it particularly dangerous in networked environments where email services are accessible to external parties.
The operational impact of this vulnerability extends beyond simple service disruption, as it can compromise the overall security posture of systems relying on ClamAV for email protection. Organizations that depend on ClamAV for email filtering and malware detection face potential exposure to prolonged service outages that could allow malicious email traffic to bypass other security controls. The vulnerability affects systems where ClamAV is configured to scan incoming email messages, particularly those configured as mail servers or email security gateways. This DoS condition can be particularly damaging in enterprise environments where email availability is critical for business operations and where the antivirus system serves as a primary defense mechanism against email-based threats.
From a cybersecurity framework perspective, this vulnerability aligns with CWE-121, which describes the condition of stack-based buffer overflow, and represents a classic example of insufficient input validation as outlined in CWE-20. The attack vector maps to MITRE ATT&CK technique T1499.004, which covers network denial of service attacks, and T1078.002, which addresses valid accounts for lateral movement. Organizations should prioritize immediate remediation by upgrading to ClamAV versions 0.99.3 or later, where the input validation has been strengthened to prevent the buffer overflow condition. Additionally, network segmentation and email filtering rules can provide temporary mitigation while maintaining system availability, though these measures do not address the root cause of the vulnerability. The incident underscores the critical importance of maintaining up-to-date security software and implementing robust input validation controls across all system components to prevent similar vulnerabilities from being exploited in the future.