CVE-2005-1249 in Ipswitch Collaboration Suite
Summary
by MITRE
The IMAP daemon (IMAPD32.EXE) in Ipswitch Collaboration Suite (ICS) allows remote attackers to cause a denial of service (CPU consumption) via an LSUB command with a large number of null characters, which causes an infinite loop.
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Analysis
by VulDB Data Team • 04/12/2019
The vulnerability identified as CVE-2005-1249 represents a critical denial of service flaw within the Ipswitch Collaboration Suite IMAP daemon implementation. This vulnerability specifically affects the IMAPD32.EXE process that handles Internet Message Access Protocol communications, making it a significant concern for email server security. The issue stems from inadequate input validation and processing logic within the LSUB command handler, which is part of the standard IMAP protocol for listing mailboxes. When an attacker sends a malicious LSUB command containing an excessive number of null characters, the daemon fails to properly sanitize this input, leading to a predictable system failure pattern.
The technical exploitation of this vulnerability occurs through a specific command injection pattern that triggers an infinite loop within the IMAP daemon's processing routine. The LSUB command, designed to list subscribed mailboxes, becomes a vector for resource exhaustion when malformed input containing numerous null characters is processed. This flaw demonstrates poor defensive programming practices and highlights the absence of proper bounds checking and input sanitization mechanisms. The null character flooding technique exploits the daemon's inability to handle excessive input length gracefully, causing the system to consume 100% CPU resources in an endless processing cycle. This behavior aligns with CWE-770, which addresses the allocation of resources without proper limits, and represents a classic example of resource exhaustion attacks.
The operational impact of this vulnerability extends beyond simple service disruption, as it can be leveraged by attackers to systematically degrade system performance and availability. Network administrators and security teams face the challenge of monitoring for such attacks, as they typically appear as legitimate protocol traffic but result in significant computational overhead. The vulnerability affects the entire Ipswitch Collaboration Suite ecosystem, potentially compromising email services for organizations relying on this platform. Attackers can maintain sustained denial of service conditions without requiring authentication, making this particularly dangerous in environments where email services are critical for business operations. The attack vector demonstrates characteristics consistent with ATT&CK technique T1499.004, which involves network denial of service through resource exhaustion attacks.
Mitigation strategies for CVE-2005-1249 require both immediate defensive measures and long-term architectural improvements. Organizations should implement input validation controls at network boundaries to filter out suspicious LSUB commands containing excessive null characters, effectively preventing the exploit from reaching the vulnerable daemon. Network security appliances and firewalls can be configured with custom rules to detect and block such malformed IMAP traffic patterns. Additionally, system administrators should consider implementing rate limiting and connection throttling mechanisms to prevent single clients from consuming excessive resources. The recommended solution involves applying the official Ipswitch patch or upgrading to a newer version of the Collaboration Suite that addresses this specific input handling vulnerability. System monitoring should be enhanced to detect unusual CPU consumption patterns that may indicate exploitation attempts, and regular security audits should verify proper input sanitization across all protocol handlers. Organizations should also consider implementing intrusion detection systems specifically configured to identify this type of resource exhaustion attack pattern.