CVE-2003-0280 in CMailServer
Summary
by MITRE
Multiple buffer overflows in the SMTP Service for ESMTP CMailServer 4.0.2003.03.27 allow remote attackers to execute arbitrary code via long (1) MAIL FROM or (2) RCPT TO commands.
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Analysis
by VulDB Data Team • 08/20/2025
The vulnerability identified as CVE-2003-0280 represents a critical security flaw in the ESMTP CMailServer 4.0.2003.03.27 SMTP service implementation. This issue manifests as multiple buffer overflow conditions that occur when processing specific SMTP commands, particularly those related to email address handling. The vulnerability resides in the server's parsing logic for the MAIL FROM and RCPT TO commands, which are fundamental components of the Simple Mail Transfer Protocol used for email transmission between servers. These buffer overflows create exploitable conditions that can be leveraged by remote attackers to gain unauthorized control over the affected system.
The technical nature of this vulnerability stems from improper input validation within the SMTP service's command processing routines. When the server receives MAIL FROM or RCPT TO commands containing excessively long arguments, the application fails to properly bounds-check the input data before copying it into fixed-length buffers. This classic buffer overflow condition allows attackers to overwrite adjacent memory locations, potentially including return addresses and function pointers, enabling arbitrary code execution. The vulnerability operates at the protocol level, making it particularly dangerous as it can be exploited through standard email transmission mechanisms without requiring authentication or specialized access.
The operational impact of this vulnerability extends beyond simple code execution, as it provides attackers with full control over the affected mail server. Once exploited, an attacker can gain shell access to the compromised system, potentially leading to data theft, email spoofing, or use of the server as a launch point for further attacks against other systems within the network. The vulnerability affects organizations relying on the ESMTP CMailServer implementation, particularly those with open mail relay configurations or systems handling high volumes of email traffic. The remote nature of the exploit means that attackers can leverage this vulnerability from anywhere on the internet, making it a significant threat to email infrastructure security.
Mitigation strategies for this vulnerability should include immediate patching of the affected ESMTP CMailServer version to the latest available security update from the vendor. Organizations should also implement network-level protections such as SMTP command filtering and input length restrictions to prevent exploitation attempts. Network segmentation and access controls should be enforced to limit exposure of mail servers to untrusted networks. Security monitoring should include detection of unusually long MAIL FROM and RCPT TO commands that may indicate exploitation attempts. From a compliance perspective, this vulnerability aligns with CWE-121, which addresses stack-based buffer overflow conditions, and relates to ATT&CK technique T1190 for exploitation of remote services. Organizations should also consider implementing email security solutions that can detect and block malformed SMTP commands before they reach the vulnerable server implementation.