CVE-2001-1419 in Instant Messenger
Summary
by MITRE
AOL Instant Messenger (AIM) 4.7.2480 and earlier allows remote attackers to cause a denial of service (application crash) via an instant message that contains a large amount of "<!--" HTML comments.
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Analysis
by VulDB Data Team • 11/13/2024
The vulnerability identified as CVE-2001-1419 represents a classic denial of service flaw affecting AOL Instant Messenger version 4.7.2480 and earlier implementations. This security weakness specifically targets the message parsing functionality within the AIM client software, creating a condition where maliciously crafted instant messages can trigger application instability. The vulnerability exploits a fundamental parsing mechanism that fails to properly handle excessive HTML comment sequences, leading to resource exhaustion and subsequent application termination. Such flaws typically arise from inadequate input validation and buffer management within legacy software implementations that were not designed with comprehensive security considerations in mind.
The technical exploitation mechanism relies on the insertion of an excessive number of HTML comment markers in the form of "<!--" into instant messages transmitted between AIM users. When the vulnerable client processes these messages, the parsing engine encounters an abnormal concentration of comment delimiters that can overwhelm the application's memory management systems. This particular flaw falls under the category of resource exhaustion attacks where the malicious input causes the application to consume excessive computational resources, ultimately resulting in a complete application crash. The vulnerability demonstrates characteristics consistent with CWE-129, which addresses improper handling of input boundaries, and CWE-400, which covers resource exhaustion conditions in software applications.
The operational impact of this vulnerability extends beyond simple service disruption to potentially compromise user experience and system reliability within environments where AIM is extensively used. Attackers can exploit this weakness to repeatedly crash AIM clients, effectively preventing users from communicating through the service. In enterprise or organizational settings, this could result in significant productivity losses and communication breakdowns. The vulnerability also represents a potential vector for larger-scale attacks where multiple simultaneous exploitation attempts could overwhelm network resources or target multiple users concurrently. This type of attack aligns with ATT&CK technique T1499.004, which covers network denial of service attacks, and demonstrates how seemingly benign input handling can become a critical security concern.
Mitigation strategies for CVE-2001-1419 primarily involve immediate software updates and patches provided by AOL to address the specific parsing flaw in affected versions. Users should implement network-level filtering to identify and block instant messages containing excessive HTML comment sequences, though this approach may not be comprehensive given the variability of attack vectors. Additionally, implementing rate limiting and message size restrictions within AIM client configurations can help reduce the impact of such attacks. Organizations should consider deploying network monitoring solutions to detect unusual patterns of AIM traffic that might indicate exploitation attempts. The vulnerability also underscores the importance of input sanitization and proper boundary checking in application development, particularly for legacy software systems that may not have undergone comprehensive security reviews. Regular security assessments and vulnerability scanning of deployed messaging systems remain essential practices for identifying and addressing similar weaknesses in communication protocols and instant messaging applications.