CVE-2002-1073 in Mercur Mailserver
Summary
by MITRE
Buffer overflow in the control service for MERCUR Mailserver 4.2 allows remote attackers to execute arbitrary code via a long password.
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Analysis
by VulDB Data Team • 09/09/2025
The vulnerability identified as CVE-2002-1073 represents a critical buffer overflow flaw within the control service of MERCUR Mailserver version 4.2. This security weakness resides in the authentication handling mechanism where the system fails to properly validate the length of password inputs submitted by remote users. The flaw manifests when an attacker sends a specially crafted password string that exceeds the allocated buffer space, causing memory corruption that can be exploited to gain unauthorized system access. The vulnerability specifically affects the control service component which manages administrative functions and user authentication processes, making it a prime target for malicious actors seeking to compromise email server infrastructure.
This buffer overflow vulnerability maps to CWE-121, which describes heap-based buffer overflow conditions where insufficient bounds checking allows attackers to overwrite adjacent memory locations. The technical implementation of this flaw occurs at the application layer where the control service processes incoming authentication requests without adequate input sanitization. When the password string exceeds the predefined buffer capacity, the excess data overflows into adjacent memory segments, potentially corrupting critical program variables or execution pointers. The attack vector is remote, meaning that adversaries can exploit this vulnerability from outside the network perimeter without requiring physical access or prior authentication credentials.
The operational impact of CVE-2002-1073 extends beyond simple unauthorized access to encompass full system compromise and potential data exfiltration. Successful exploitation enables attackers to execute arbitrary code with the privileges of the affected service account, which typically operates with elevated permissions on the mail server. This privilege escalation capability allows malicious actors to install backdoors, modify email content, access confidential communications, or use the compromised server as a launching point for further attacks against internal network resources. The vulnerability particularly affects organizations relying on MERCUR Mailserver 4.2 for email services, as it provides a straightforward path to system infiltration that requires minimal technical expertise to exploit.
Organizations should implement immediate mitigations including applying vendor-provided patches or updates to MERCUR Mailserver 4.2 to address the buffer overflow condition. System administrators should also consider implementing network-level restrictions that limit access to the control service ports and enforce strong authentication mechanisms. The ATT&CK framework categorizes this vulnerability under T1210 - Exploitation of Remote Services, highlighting the importance of network segmentation and service hardening practices. Additional defensive measures include monitoring for unusual authentication patterns, implementing intrusion detection systems to identify potential exploitation attempts, and conducting regular vulnerability assessments to identify similar buffer overflow conditions in other legacy systems. Organizations should also consider migrating from unsupported software versions to modern email server solutions that incorporate robust input validation and memory protection mechanisms.