CVE-2006-1337 in MailEnable
Summary
by MITRE
Buffer overflow in the POP 3 (POP3) service in MailEnable Standard Edition before 1.93, Professional Edition before 1.73, and Enterprise Edition before 1.21 allows remote attackers to execute arbitrary code via unknown vectors before authentication.
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Analysis
by VulDB Data Team • 06/15/2019
The vulnerability identified as CVE-2006-1337 represents a critical buffer overflow flaw within the pop3 service component of MailEnable email server software. This security weakness exists in multiple editions of the software including Standard, Professional, and Enterprise versions with specific affected versions being before 1.93, 1.73, and 1.21 respectively. The vulnerability's severity stems from its ability to allow remote code execution without requiring prior authentication, making it particularly dangerous as attackers can exploit this flaw from external networks without needing valid credentials. The buffer overflow occurs within the pop3 service implementation, which processes incoming email commands and responses, creating a potential attack surface where malformed input can cause memory corruption and arbitrary code execution.
The technical nature of this vulnerability aligns with CWE-121, which categorizes buffer overflow conditions where insufficient bounds checking allows attackers to write beyond allocated memory buffers. This particular flaw operates at the protocol level within the pop3 service, which is designed to handle email retrieval commands from clients. The attack vector involves sending specially crafted malformed data to the pop3 service before authentication, allowing the attacker to manipulate memory layout and potentially overwrite critical program execution elements. The vulnerability's exploitation does not require authentication because the buffer overflow occurs during the initial protocol handling phase, before the service validates user credentials or establishes secure sessions. This characteristic places the vulnerability in the ATT&CK framework under the T1203 technique category, which encompasses exploitation of software vulnerabilities to gain unauthorized access.
The operational impact of this vulnerability extends beyond simple remote code execution to encompass complete system compromise potential. An attacker who successfully exploits this buffer overflow can gain full control over the mail server system, potentially leading to data exfiltration, system infiltration, or use of the compromised server for further attacks against other network resources. The vulnerability affects organizations that rely on MailEnable for email services, particularly those with exposed pop3 ports or systems where the service is accessible from untrusted networks. The lack of authentication requirements means that any external party with knowledge of the target system can attempt exploitation, significantly increasing the attack surface. Organizations using affected versions of MailEnable are particularly vulnerable as the flaw exists in core service functionality and affects email retrieval operations that are fundamental to business communications.
Mitigation strategies for this vulnerability primarily involve immediate software patching and version updates to the affected MailEnable editions. System administrators should upgrade to versions 1.93, 1.73, and 1.21 or later for Standard, Professional, and Enterprise editions respectively, as these releases contain the necessary fixes for the buffer overflow condition. Network-level protections should include firewall rules that restrict access to pop3 ports from untrusted networks, limiting exposure to external attackers. Additionally, implementing network segmentation and access controls can reduce the potential impact if exploitation occurs. Monitoring network traffic for unusual pop3 protocol activity and implementing intrusion detection systems can help identify exploitation attempts. Organizations should also consider disabling pop3 services entirely if they are not required for business operations, as this eliminates the attack surface. The vulnerability demonstrates the importance of regular software updates and security assessments, as the flaw existed in widely deployed email server software and could be exploited by attackers with minimal technical expertise. System hardening practices including disabling unnecessary services, implementing strong access controls, and maintaining current security patches should be part of comprehensive security strategies to prevent similar vulnerabilities from being exploited in the future.