CVE-2024-24736 in YahooPOPs
Summary
by MITRE • 01/29/2024
The POP3 service in YahooPOPs (aka YPOPs!) 1.6 allows a remote denial of service (reboot) via a long string to TCP port 110, a related issue to CVE-2004-1558.
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Analysis
by VulDB Data Team • 06/21/2025
The vulnerability identified as CVE-2024-24736 affects the POP3 service implementation within YahooPOPs version 1.6, representing a significant remote denial of service weakness that can be exploited to cause system reboot. This issue specifically targets TCP port 110 which is the standard port for POP3 email services, making it a critical vector for attackers seeking to disrupt email infrastructure. The flaw manifests when a malicious actor sends an excessively long string to the POP3 service, triggering a system crash that results in complete service interruption and potential system reboot. This vulnerability demonstrates the continued relevance of legacy software security issues, as it shares similarities with CVE-2004-1558, indicating that fundamental buffer overflow patterns persist in older email server implementations. The attack surface is particularly concerning given that POP3 services remain in use within various enterprise environments despite the availability of more modern protocols, creating persistent exposure points for organizations that have not migrated to contemporary email solutions.
The technical implementation of this vulnerability stems from inadequate input validation within the YahooPOPs POP3 service handler, where the software fails to properly sanitize or limit the length of incoming data strings before processing them. When the service receives a malformed string exceeding predetermined buffer limits, it triggers undefined behavior that results in memory corruption and ultimately system instability. This type of vulnerability aligns with CWE-121, which describes heap-based buffer overflow conditions, and CWE-122, which covers stack-based buffer overflow scenarios. The implementation flaw occurs at the protocol parsing layer where the POP3 service does not enforce reasonable string length constraints during command processing, allowing attackers to craft malicious payloads that exploit memory management weaknesses in the application's handling of user input.
From an operational perspective, the impact of CVE-2024-24736 extends beyond simple service disruption to encompass potential business continuity risks for organizations relying on affected YahooPOPs installations. The remote nature of the exploit means that attackers can initiate attacks from anywhere on the internet without requiring physical access or local credentials, making it particularly dangerous for organizations with exposed email services. The vulnerability's ability to cause system reboot rather than merely service interruption increases the operational impact, as it may result in data loss, extended downtime, and potential compromise of email archives that were not properly backed up before the attack. Additionally, the fact that this vulnerability affects a service that has been in use for many years suggests that organizations may not have adequate security monitoring in place to detect such attacks, potentially allowing attackers to maintain persistent access or conduct extended disruption campaigns.
Organizations should implement immediate mitigations including network segmentation to restrict access to TCP port 110, deployment of intrusion detection systems with signature matching for known malicious string patterns, and implementation of rate limiting controls to prevent rapid exploitation attempts. The most effective long-term solution involves complete migration away from YahooPOPs 1.6 to modern email server implementations that have proper input validation and memory safety protections. Security teams should also consider implementing network access controls to limit exposure of POP3 services to internal networks only, and establish monitoring procedures to detect unusual traffic patterns on port 110. According to ATT&CK framework, this vulnerability maps to T1499.004 which covers network denial of service attacks, and T1595.001 which involves network scanning and reconnaissance activities that would precede exploitation of such vulnerabilities. Regular security assessments should include legacy system inventory reviews to identify other potentially vulnerable services that may share similar implementation flaws, as this represents a broader class of vulnerabilities that persist in older software implementations.