CVE-2008-0394 in SMTP server
Summary
by MITRE
Buffer overflow in Citadel SMTP server 7.10 and earlier allows remote attackers to execute arbitrary code via a long RCPT TO command, which is not properly handled by the makeuserkey function. NOTE: some of these details were obtained from third party information.
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Analysis
by VulDB Data Team • 10/14/2024
The CVE-2008-0394 vulnerability represents a critical buffer overflow flaw in the Citadel SMTP server version 7.10 and earlier implementations. This vulnerability specifically targets the makeuserkey function within the email server software, which fails to properly validate the length of RCPT TO commands submitted during the email delivery process. The issue arises when remote attackers craft maliciously long RCPT TO command sequences that exceed the allocated buffer space, triggering the buffer overflow condition that can be exploited to execute arbitrary code on the affected system.
The technical exploitation of this vulnerability occurs through the manipulation of the Simple Mail Transfer Protocol (SMTP) communication flow where the RCPT TO command specifies the recipient address for email messages. When the Citadel server processes these commands without adequate input validation, the makeuserkey function becomes susceptible to overflow conditions that can overwrite adjacent memory locations. This memory corruption typically allows attackers to redirect program execution flow and inject malicious code into the running process, potentially gaining full control over the server. The vulnerability falls under CWE-121, which specifically addresses stack-based buffer overflow conditions, and aligns with ATT&CK technique T1190 for exploit development through buffer overflow attacks.
The operational impact of this vulnerability extends beyond simple remote code execution, as it provides attackers with persistent access to the email server infrastructure. Once exploited, adversaries can leverage the compromised system to conduct further attacks including email spoofing, data exfiltration, or using the server as a launchpad for attacking other network resources. The vulnerability affects organizations relying on Citadel email servers for business communications, potentially exposing sensitive corporate email data and disrupting critical email services. The remote nature of the attack means that exploitation can occur from anywhere on the internet without requiring physical access to the target system, making it particularly dangerous for organizations with exposed SMTP services.
Mitigation strategies for CVE-2008-0394 should prioritize immediate patching of the Citadel SMTP server software to version 7.11 or later, which includes proper input validation for RCPT TO commands. Network administrators should implement proper access controls and firewall rules to limit SMTP service exposure to trusted networks only, reducing the attack surface for this vulnerability. Additionally, monitoring systems should be configured to detect unusual RCPT TO command patterns that might indicate exploitation attempts, while regular security audits should verify that no unauthorized modifications have occurred on the email server infrastructure. Organizations should also consider implementing intrusion detection systems that can identify buffer overflow patterns in network traffic and maintain updated threat intelligence feeds to stay informed about similar vulnerabilities in other email server implementations.