CVE-2000-1152 in Browser IRC Client
Summary
by MITRE
Browser IRC client in BeOS r5 pro and earlier allows remote attackers to conduct a denial of service via a message that contains a long URL.
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Analysis
by VulDB Data Team • 04/07/2019
The vulnerability described in CVE-2000-1152 represents a classic denial of service flaw affecting the browser-based IRC client component of BeOS r5 and earlier versions. This issue specifically targets the handling of malformed message content containing excessively long URLs within the IRC communication protocol implementation. The affected system components operate within the BeOS operating system environment, which was designed for multimedia and network applications, making this vulnerability particularly concerning for users relying on IRC for real-time communication. The vulnerability resides in the client-side message parsing logic that fails to properly validate or limit the length of URL strings contained within IRC messages.
The technical root cause of this vulnerability stems from inadequate input validation within the IRC client's message processing pipeline. When the client receives an IRC message containing an abnormally long URL, the parsing routine does not implement proper bounds checking or length limitations for URL content. This lack of validation creates a condition where the application's memory management and string handling routines can be overwhelmed by excessively long input sequences. The flaw operates at the application layer, specifically within the protocol implementation that processes incoming IRC messages, making it a type of buffer overflow or resource exhaustion vulnerability. According to CWE classification, this corresponds to CWE-122: Heap-based Buffer Overflow or CWE-770: Allocation of Resources Without Limits or Throttling, depending on the specific memory management implementation details. The vulnerability demonstrates poor defensive programming practices where the system assumes all input will be of reasonable length without implementing proper sanitization measures.
The operational impact of this vulnerability is significant for users operating BeOS systems with affected IRC clients, as it allows remote attackers to disrupt service availability without requiring any authentication or privileged access. An attacker can simply send a specially crafted IRC message containing an extremely long URL to any user running the vulnerable client software, causing the application to consume excessive system resources or crash entirely. This denial of service condition affects the core communication functionality of the IRC client, preventing legitimate users from participating in chat sessions or receiving messages. The vulnerability can be exploited at scale through automated tools that generate and broadcast malicious messages to multiple targets simultaneously, potentially causing widespread disruption in IRC networks. The attack vector is particularly dangerous because it requires no specialized knowledge of the target system beyond the ability to send IRC messages, making it accessible to attackers with minimal technical expertise.
Mitigation strategies for this vulnerability should focus on implementing proper input validation and resource limiting measures within the IRC client implementation. System administrators should immediately upgrade to BeOS versions that contain patched IRC client components, as the vulnerability affects the core operating system functionality. The recommended approach involves implementing strict length limitations for URL content within IRC messages, typically capping URL lengths at reasonable values such as 2048 characters or less. Additionally, the client should implement proper error handling and graceful degradation when encountering malformed input, rather than allowing the application to crash or consume excessive resources. Security controls should include input sanitization routines that strip or truncate excessive URL content before processing, and monitoring systems should be implemented to detect unusual message patterns that might indicate exploitation attempts. This vulnerability aligns with ATT&CK technique T1499.004: Network Denial of Service, which focuses on disrupting network services through resource exhaustion attacks. Organizations should also consider implementing network-level filtering to limit the size of messages passing through IRC channels, providing an additional layer of defense against such attacks.