CVE-2007-5467 in eXtremail
Summary
by MITRE
Integer overflow in eXtremail 2.1.1 and earlier allows remote attackers to cause a denial of service, and possibly execute arbitrary code, via a long USER command containing "%s" sequences to the pop3 port (110/tcp), which are expanded to "%%s" before being used in the memmove function, possibly due to an incomplete fix for CVE-2001-1078.
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Analysis
by VulDB Data Team • 06/02/2025
The vulnerability described in CVE-2007-5467 represents a critical integer overflow flaw within the eXtremail email server software version 2.1.1 and earlier. This issue specifically affects the pop3 service running on port 110/tcp and stems from inadequate input validation mechanisms that fail to properly handle malformed user commands containing "%s" format specifiers. The vulnerability manifests when a remote attacker crafts a malicious USER command with extended format string sequences that trigger buffer manipulation errors during command processing. The flaw is particularly concerning as it was identified as an incomplete remediation for a previous vulnerability CVE-2001-1078, indicating that the original fix failed to address all potential attack vectors within the software's memory management functions.
The technical exploitation of this vulnerability occurs through the manipulation of the memmove function, which is responsible for copying memory blocks during command processing. When the eXtremail server receives a USER command containing "%s" sequences, these are expanded to "%%s" format specifiers before being processed by the memmove function. This transformation creates an integer overflow condition that can result in memory corruption, allowing attackers to potentially execute arbitrary code with the privileges of the mail server process. The vulnerability operates at the intersection of buffer overflow and format string exploitation techniques, creating a complex attack surface that leverages both integer arithmetic errors and memory manipulation functions. The integer overflow specifically impacts the calculation of buffer sizes used in memory operations, causing the application to allocate insufficient memory for processing the expanded format strings.
The operational impact of this vulnerability extends beyond simple denial of service conditions to potentially enable full system compromise. Remote attackers can leverage this flaw to cause the eXtremail service to crash or become unresponsive, resulting in denial of email services for legitimate users. More critically, the integer overflow condition can be manipulated to overwrite critical memory locations, potentially allowing attackers to inject and execute malicious code within the server environment. This capability places the entire email infrastructure at risk, as successful exploitation could lead to unauthorized access to email communications, data exfiltration, and potential lateral movement within network environments where the vulnerable mail server operates. The vulnerability affects organizations relying on eXtremail for email services, particularly those with limited security monitoring or patch management capabilities.
Mitigation strategies for CVE-2007-5467 require immediate implementation of software updates to versions that properly address the integer overflow conditions in the memmove function processing. Organizations should prioritize patching the eXtremail software to versions that contain complete fixes for both CVE-2007-5467 and the related CVE-2001-1078 vulnerabilities. Network-level defenses should include monitoring for suspicious USER command patterns on port 110/tcp and implementing rate limiting or connection filtering mechanisms to prevent exploitation attempts. System administrators should also consider implementing intrusion detection systems that can identify format string manipulation patterns and anomalous memory access behaviors. The vulnerability aligns with CWE-190, which categorizes integer overflow conditions, and represents a specific instance of CWE-122, concerning buffer overflow through improper input validation. From an attack framework perspective, this vulnerability maps to ATT&CK technique T1203, focusing on exploitation for privilege escalation, and T1499, covering denial of service attacks through resource exhaustion or memory corruption. Organizations should conduct thorough security assessments to identify any remaining instances of vulnerable eXtremail installations and implement comprehensive monitoring to detect potential exploitation attempts.