CVE-2017-12380 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 in mbox.c during certain mail parsing functions of the ClamAV software. An unauthenticated, remote attacker could exploit this vulnerability by sending a crafted email to the affected device. An exploit could trigger a NULL pointer dereference condition when ClamAV scans the malicious email, which may result in a DoS condition.
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Analysis
by VulDB Data Team • 02/02/2023
The vulnerability identified as CVE-2017-12380 resides within ClamAV AntiVirus software versions 0.99.2 and earlier, representing a critical denial of service weakness that can be exploited remotely without authentication. This flaw specifically manifests in the mbox.c file where mail parsing functions fail to properly validate input data, creating an exploitable condition that affects the software's ability to process email messages safely. The issue stems from inadequate boundary checking and validation mechanisms that should normally prevent malformed data from causing system instability during routine scanning operations.
The technical exploitation of this vulnerability occurs through a carefully crafted email message that triggers a NULL pointer dereference condition within the ClamAV scanning engine. When the affected software attempts to parse the malicious email through its mbox parsing functions, the improper input validation allows malformed data to bypass normal processing checks. This failure results in the software attempting to access a null memory pointer, causing an immediate crash or system hang that effectively renders the antivirus service unavailable. The vulnerability operates at the application layer and can be triggered remotely, making it particularly dangerous for networked systems that rely on ClamAV for email scanning and threat detection.
From an operational impact perspective, this vulnerability creates significant risk for organizations that depend on ClamAV for email security filtering and malware detection. The remote denial of service condition can disrupt email services, prevent legitimate email processing, and potentially impact business continuity if the affected systems are critical infrastructure components. The attack vector requires only the ability to send an email to the target system, making exploitation straightforward and accessible to attackers with minimal technical expertise. Organizations may experience service interruptions, increased administrative overhead for system recovery, and potential escalation to more complex security incidents if the DoS condition affects multiple systems or network segments.
The vulnerability aligns with CWE-476, which describes NULL pointer dereference conditions that occur when software attempts to access memory through a null reference without proper validation. This weakness represents a common class of software flaws that can lead to system instability and denial of service conditions, particularly in security applications where input validation is critical for maintaining system integrity. The attack pattern follows typical remote exploitation techniques described in the MITRE ATT&CK framework under the T1499 category for network denial of service attacks. Organizations should consider implementing network segmentation, email filtering rules, and monitoring for unusual scanning activity as part of their defensive strategy. The recommended mitigation involves upgrading to ClamAV version 0.99.3 or later, which includes proper input validation fixes that prevent the NULL pointer dereference condition from occurring during email parsing operations.