CVE-2002-0432 in Citadel
Summary
by MITRE
Buffer overflow in (1) lprintf and (2) cprintf in sysdep.c of Citadel/UX 5.90 and earlier allows remote attackers to cause a denial of service (crash) and possibly execute arbitrary code via attacks such as a long HELO command to the SMTP server.
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Analysis
by VulDB Data Team • 06/18/2024
The vulnerability described in CVE-2002-0432 represents a critical buffer overflow flaw affecting Citadel/UX versions 5.90 and earlier. This issue manifests in two distinct functions within the sysdep.c file namely lprintf and cprintf which are responsible for handling printf-style formatting operations within the system's socket communication layer. The vulnerability specifically targets the SMTP server component where these functions process incoming commands from remote clients. When an attacker sends a malformed HELO command containing an excessively long string parameter the vulnerable functions fail to properly validate input length before copying data into fixed-size buffers. This classic buffer overflow condition occurs because the implementation does not perform adequate bounds checking on user-supplied data before writing to memory locations that are insufficiently sized to accommodate the input.
The technical impact of this vulnerability extends beyond simple denial of service to potentially enabling remote code execution. When the buffer overflow occurs during processing of the HELO command the stack-based memory corruption can overwrite critical program execution elements including return addresses and function pointers. This memory corruption creates opportunities for attackers to manipulate program flow and potentially inject malicious code that executes with the privileges of the affected SMTP service. The vulnerability is particularly concerning because it operates at the network level where the SMTP server listens for incoming connections, making it accessible to any remote attacker capable of establishing SMTP sessions. The flaw demonstrates a fundamental lack of input validation and memory management practices that are essential for secure system design.
The operational impact of CVE-2002-0432 poses significant risks to organizations relying on Citadel/UX email services. A successful exploitation could result in complete system compromise allowing attackers to gain unauthorized access to email communications, potentially access sensitive data stored within the email server, and establish persistent access points within the network infrastructure. The vulnerability's remote exploitability means that attackers do not require local system access or physical presence to carry out attacks. Organizations using affected versions of Citadel/UX face potential data breaches, service interruptions, and regulatory compliance violations. The flaw also demonstrates poor defensive programming practices that could affect other components of the system where similar buffer handling issues might exist, making the overall security posture of affected systems significantly weaker.
Mitigation strategies for this vulnerability should prioritize immediate patching of affected systems with the vendor-supplied security updates. Organizations should also implement network-level defenses including firewall rules that restrict SMTP service access to trusted networks and implement intrusion detection systems that can identify suspicious HELO command patterns. The vulnerability aligns with CWE-121 Stack-based Buffer Overflow and CWE-787 Out-of-bounds Write categories, and maps to ATT&CK technique T1203 Exploitation for Client Execution and T1499 Endpoint Denial of Service. Additional defensive measures include implementing input validation at multiple layers of the system architecture, configuring proper memory protection mechanisms such as stack canaries, and conducting regular security audits to identify similar buffer handling flaws. System administrators should also consider implementing network segmentation to limit the potential impact of successful exploitation and establish comprehensive monitoring protocols to detect unusual SMTP traffic patterns that might indicate attempted exploitation attempts.