CVE-2005-4411 in Mercury Mail Transport System
Summary
by MITRE
Buffer overflow in Mercury Mail Transport System 4.01b allows remote attackers to execute arbitrary code via a long request to TCP port 105.
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Analysis
by VulDB Data Team • 06/16/2024
The Mercury Mail Transport System version 4.01b contains a critical buffer overflow vulnerability that exists in its handling of incoming network requests on TCP port 105. This port typically serves the POP3 email protocol, making the vulnerability particularly dangerous as it can be exploited by remote attackers without requiring authentication. The buffer overflow occurs when the system receives a malformed request that exceeds the allocated buffer space, causing memory corruption that can be leveraged to execute arbitrary code on the affected system.
This vulnerability represents a classic stack-based buffer overflow flaw that aligns with CWE-121, which describes conditions where insufficient bounds checking allows an attacker to overwrite adjacent memory locations. The flaw specifically affects the protocol handling component of Mercury Mail, where input validation is inadequate to prevent excessive data from being copied into fixed-length buffers. The attack vector is remote and accessible over the network, making it highly exploitable in environments where the service is exposed to untrusted networks.
The operational impact of this vulnerability extends beyond simple code execution, as successful exploitation can lead to complete system compromise and unauthorized access to email communications. Attackers can leverage this vulnerability to gain shell access, install backdoors, or escalate privileges within the system. The vulnerability affects the core mail transport functionality, potentially allowing attackers to read, modify, or delete email messages, access user credentials, or use the compromised system as a pivot point for further attacks within the network. Organizations running this version of Mercury Mail are particularly at risk since the service typically operates with elevated privileges to handle mail processing tasks.
Mitigation strategies for this vulnerability should include immediate patching of the Mercury Mail Transport System to version 4.02 or later, which contains the necessary fixes for the buffer overflow condition. Network segmentation and firewall rules should be implemented to restrict access to TCP port 105, limiting exposure to trusted networks only. Additionally, intrusion detection systems should be configured to monitor for unusual traffic patterns on port 105 that might indicate exploitation attempts. The vulnerability demonstrates the importance of input validation and proper bounds checking in network services, aligning with ATT&CK technique T1203 for legitimate credentials and T1059 for command and control through compromised systems. Organizations should also consider implementing application whitelisting and regular security assessments to identify similar vulnerabilities in other legacy systems that may be running outdated software versions.