CVE-2017-12374 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 operations (mbox.c operations on bounce messages). If successfully exploited, the ClamAV software could allow a variable pointing to the mail body which could cause a used after being free (use-after-free) instance which may lead to a disruption of services on an affected device to include a denial of service condition.
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Analysis
by VulDB Data Team • 02/02/2023
The vulnerability identified as CVE-2017-12374 affects ClamAV antivirus software versions 0.99.2 and earlier, representing a critical security flaw that enables remote attackers to execute denial of service attacks without authentication. This weakness specifically manifests during mail parsing operations within the mbox.c component when processing bounce messages, creating a dangerous scenario where the software's memory management becomes compromised. The vulnerability stems from insufficient input validation mechanisms that fail to properly sanitize or verify the integrity of incoming mail data during the parsing process, particularly when handling malformed or specially crafted email structures.
The technical exploitation of this vulnerability results in a use-after-free condition, a common memory corruption flaw that occurs when the software attempts to access memory that has already been deallocated or freed from memory. In the context of ClamAV's mbox.c operations, this happens when a variable pointer referencing the mail body content is improperly managed during bounce message processing, leading to the software attempting to access freed memory locations. This memory corruption scenario typically occurs when the application processes malformed email headers or body content that triggers unexpected execution paths in the parsing logic, ultimately causing the application to crash or become unresponsive.
The operational impact of this vulnerability extends beyond simple service disruption, as it can affect organizations relying on ClamAV for email security filtering and malware detection. When exploited, the use-after-free condition can cause the ClamAV daemon to terminate unexpectedly, requiring manual intervention to restart the service and potentially leaving the system vulnerable during the downtime period. Network administrators may experience cascading effects where email services become unavailable, and the system may require complete restarts to restore normal operations. The vulnerability's remote nature means attackers can exploit it from any location without requiring local system access or authentication credentials, making it particularly dangerous for organizations with exposed email servers or network infrastructure.
Organizations should immediately upgrade to ClamAV version 0.99.3 or later, which contains the necessary patches to address this memory corruption vulnerability. Security teams should also implement network monitoring to detect potential exploitation attempts and consider deploying temporary network segmentation or firewall rules to limit access to ClamAV services. The vulnerability aligns with CWE-416, which describes the use-after-free error condition, and represents a typical example of how insufficient input validation can lead to memory corruption vulnerabilities. From an ATT&CK framework perspective, this vulnerability maps to the T1499.004 technique related to network disruption and the T1566.001 technique for social engineering through email, as it specifically targets email processing capabilities that organizations depend upon for security operations.
The root cause of this vulnerability demonstrates the critical importance of proper memory management and input validation in security software, particularly in applications that process untrusted data such as email messages. Software developers should implement comprehensive testing procedures including fuzzing and memory debugging tools to identify similar issues before deployment. Organizations should also maintain updated threat intelligence feeds to monitor for exploitation attempts and ensure their security tooling remains current with the latest vulnerability patches. Regular security assessments and penetration testing of email security infrastructure can help identify additional weaknesses that may compound the risks associated with vulnerabilities like CVE-2017-12374, ensuring comprehensive protection against both known and emerging threats in the cybersecurity landscape.