CVE-1999-1532 in Messaging Server
Summary
by MITRE
Netscape Messaging Server 3.54, 3.55, and 3.6 allows a remote attacker to cause a denial of service (memory exhaustion) via a series of long RCPT TO commands.
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Analysis
by VulDB Data Team • 12/02/2024
The vulnerability described in CVE-1999-1532 represents a classic denial of service flaw affecting Netscape Messaging Server versions 3.54, 3.55, and 3.56. This issue stems from the server's inadequate handling of email recipient commands during the SMTP communication process, specifically when processing a series of long RCPT TO commands. The vulnerability operates at the application layer of the network stack, targeting the mail server's message processing capabilities and represents a significant security concern for organizations relying on legacy email infrastructure.
The technical flaw manifests when a remote attacker sends multiple RCPT TO commands containing excessively long email addresses or recipient identifiers to the affected messaging server. The server fails to properly validate or limit the length of these commands, causing it to allocate increasingly large amounts of memory to process each command. This memory allocation behavior creates a progressive consumption pattern that can quickly exhaust the server's available memory resources, ultimately leading to a complete denial of service condition where legitimate email services become unavailable to users. The vulnerability operates under CWE-400, specifically addressing unchecked resource consumption, and demonstrates poor input validation practices that allow malicious actors to exploit the server's memory management mechanisms.
The operational impact of this vulnerability extends beyond simple service disruption, as it can severely compromise email availability for organizations using the affected Netscape Messaging Server versions. When exploited, the denial of service condition can persist until the server is manually restarted or the memory exhaustion is resolved through system-level intervention. This vulnerability particularly affects email infrastructure that relies on SMTP protocol handling, where the RCPT TO command is used to specify recipient addresses during email transmission. The attack vector is particularly dangerous because it requires minimal privileges and can be executed remotely, making it an attractive target for attackers seeking to disrupt email services. Organizations experiencing this vulnerability may face significant operational downtime and potential business disruption as email communication becomes unavailable.
Mitigation strategies for CVE-1999-1532 should focus on implementing proper input validation and resource limiting mechanisms within the messaging server configuration. Administrators should configure maximum length limits for RCPT TO commands and implement rate limiting to prevent excessive command processing. The recommended approach aligns with ATT&CK technique T1499.004, which addresses resource exhaustion attacks through proper input validation and capacity management. Additionally, organizations should consider upgrading to patched versions of the Netscape Messaging Server or migrating to more modern email infrastructure that properly handles resource allocation and input validation. Network-level protections such as firewalls and intrusion detection systems can also help by monitoring for unusual command patterns and limiting the number of commands processed from individual connections. Regular security assessments and monitoring of server resource utilization should be implemented to detect potential exploitation attempts and ensure the effectiveness of implemented mitigations.