CVE-2001-0442 in Mercury-NLM
Summary
by MITRE
Buffer overflow in Mercury MTA POP3 server for NetWare 1.48 and earlier allows remote attackers to cause a denial of service and possibly execute arbitrary code via a long APOP command.
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Analysis
by VulDB Data Team • 12/05/2024
The vulnerability identified as CVE-2001-0442 represents a critical buffer overflow flaw within the Mercury Mail Transfer Agent POP3 server implementation specifically targeting Novell NetWare systems running version 1.48 or earlier. This issue resides in the handling of APOP (Authenticated Post Office Protocol) commands, which are used for secure authentication in email systems. The flaw manifests when the server receives an excessively long APOP command that exceeds the allocated buffer space, creating a condition where malicious input can overwrite adjacent memory locations and potentially disrupt normal system operations.
The technical nature of this vulnerability aligns with CWE-121, which describes heap-based buffer overflow conditions where insufficient bounds checking allows attackers to write beyond allocated memory regions. The Mercury MTA POP3 server fails to properly validate the length of incoming APOP command parameters, creating an exploitable condition that can be leveraged by remote attackers. When an attacker sends a malformed APOP command containing more data than the buffer can accommodate, the overflow can corrupt stack memory, potentially leading to arbitrary code execution or system crashes.
From an operational perspective, this vulnerability presents significant risks to organizations relying on Mercury MTA for email services on NetWare platforms. The remote exploitation capability means that attackers do not require physical access or local privileges to exploit the flaw, making it particularly dangerous in networked environments. The potential for both denial of service and arbitrary code execution creates a dual threat scenario where system availability can be compromised while simultaneously providing attackers with possible persistence mechanisms. This vulnerability directly impacts the integrity and availability of email services, potentially affecting business operations and communication infrastructure.
The exploitation of this vulnerability can be categorized under ATT&CK technique T1203, which involves exploiting vulnerabilities in software to gain unauthorized access or execute malicious code. Organizations should implement immediate mitigations including applying vendor patches, upgrading to Mercury MTA versions 1.49 or later where this issue has been resolved, and implementing network segmentation to limit exposure. Additionally, monitoring network traffic for suspicious APOP command patterns and implementing input validation controls can help detect and prevent exploitation attempts. The vulnerability serves as a reminder of the importance of proper bounds checking in network services and demonstrates how seemingly minor implementation flaws can create significant security risks in email infrastructure components.