CVE-2007-1373 in Mercury Mail Transport System
Summary
by MITRE
Stack-based buffer overflow in Mercury/32 (aka Mercury Mail Transport System) 4.01b and earlier allows remote attackers to execute arbitrary code via a long LOGIN command. NOTE: this might be the same issue as CVE-2006-5961.
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Analysis
by VulDB Data Team • 10/09/2017
The vulnerability described in CVE-2007-1373 represents a critical stack-based buffer overflow within the Mercury/32 mail transport system version 4.01b and earlier. This flaw exists in the handling of the LOGIN command, which is a fundamental authentication mechanism used by the system. The vulnerability is particularly concerning as it allows remote attackers to execute arbitrary code on the affected system without requiring any prior authentication credentials. The buffer overflow occurs when the system processes a LOGIN command that exceeds the allocated stack buffer size, leading to memory corruption that can be exploited to gain control over the system's execution flow.
The technical nature of this vulnerability aligns with CWE-121, which describes stack-based buffer overflow conditions where insufficient bounds checking allows an attacker to overwrite adjacent memory locations. In the context of Mercury/32, when a remote attacker sends a specially crafted LOGIN command containing excessive data, the system fails to properly validate the input length before copying it into a fixed-size stack buffer. This classic buffer overflow scenario creates an opportunity for attackers to overwrite the return address on the stack, effectively redirecting program execution to malicious code injected by the attacker. The vulnerability's remote exploitability means that attackers can leverage this flaw from outside the network perimeter, making it particularly dangerous for mail servers exposed to the internet.
The operational impact of this vulnerability extends beyond simple code execution, as it can lead to complete system compromise and potential lateral movement within networks. Once an attacker gains remote code execution, they can establish persistent access, escalate privileges, and use the compromised mail server as a pivot point for attacking other systems. The vulnerability's classification as a remote code execution flaw places it within the ATT&CK framework's technique T1059.007, which covers command and scripting interpreter execution, and T1078.004, which addresses valid accounts for unauthorized access. The affected Mercury/32 system may also be vulnerable to additional attacks leveraging the compromised state, including data exfiltration, service disruption, or use as a launchpad for further network infiltration activities.
The remediation approach for this vulnerability requires immediate patching of the Mercury/32 software to version 4.02 or later, which contains the necessary fixes for the buffer overflow issue. Organizations should also implement network segmentation to limit exposure of mail servers to untrusted networks and consider implementing intrusion detection systems to monitor for suspicious LOGIN command patterns. Additionally, administrators should conduct thorough security assessments of their mail server configurations to ensure that unnecessary services are disabled and that proper access controls are in place to minimize the attack surface. The vulnerability's similarity to CVE-2006-5961 suggests that organizations should review their entire Mercury/32 deployment for related issues and ensure comprehensive patch management processes are in place to address similar vulnerabilities in other components of the system.