CVE-2004-2168 in Basomail Server
Summary
by MITRE
BaSoMail 1.24 allows remote attackers to cause a denial of service (CPU consumption) via multiple connections to TCP port (1) 25 (SMTP) or (2) 110 (POP3).
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Analysis
by VulDB Data Team • 06/23/2018
The vulnerability identified as CVE-2004-2168 affects BaSoMail 1.24, a mail server software implementation that fails to properly handle concurrent connection requests. This flaw manifests as a denial of service condition where remote attackers can exhaust system resources through sustained connection attempts to the SMTP port 25 or POP3 port 110. The vulnerability operates by exploiting the mail server's inadequate connection handling mechanisms, allowing malicious actors to consume excessive CPU cycles and effectively render the service unavailable to legitimate users. This represents a classic resource exhaustion attack pattern that targets fundamental network service operations.
The technical implementation of this vulnerability stems from insufficient input validation and connection management within the BaSoMail server software. When multiple concurrent connections are established to either the SMTP or POP3 ports, the application fails to properly terminate or limit connection handling processes. This deficiency creates a condition where each connection consumes system resources without proper cleanup or resource limitation mechanisms. The flaw aligns with CWE-400, which categorizes excessive resource consumption as a common vulnerability in software implementations. Attackers can exploit this by maintaining persistent connection attempts that prevent the server from properly managing its connection pool and processing legitimate mail requests.
The operational impact of CVE-2004-2168 extends beyond simple service disruption to potentially compromise the entire mail infrastructure. When the mail server becomes overwhelmed with connection requests, legitimate users experience delays or complete inability to send or receive emails through SMTP or POP3 protocols. This vulnerability directly affects business continuity and communication services, particularly in environments where email is critical for operations. The attack vector is particularly dangerous because it requires minimal technical expertise to execute and can be performed from any location with network access to the target server. The vulnerability also aligns with ATT&CK technique T1499.004, which covers network denial of service attacks through resource exhaustion.
Mitigation strategies for this vulnerability require both immediate and long-term approaches to secure the mail server infrastructure. The most effective immediate solution involves implementing connection rate limiting and maximum connection thresholds for both SMTP and POP3 services. Administrators should configure the mail server to reject excessive connection attempts and implement proper connection timeout mechanisms. Network-level protections such as firewall rules can be deployed to limit concurrent connections from individual IP addresses. Additionally, upgrading to a patched version of BaSoMail or migrating to a more robust mail server implementation addresses the root cause. The remediation process should include monitoring connection patterns to detect anomalous behavior and implementing automated alerts for unusual connection spikes. Organizations should also consider implementing intrusion detection systems to monitor for exploitation attempts and establish proper incident response procedures for handling such denial of service events.