CVE-2000-0046 in ICQ
Summary
by MITRE
Buffer overflow in ICQ 99b 1.1.1.1 client allows remote attackers to execute commands via a malformed URL within an ICQ message.
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Analysis
by VulDB Data Team • 06/07/2025
The vulnerability identified as CVE-2000-0046 represents a critical buffer overflow flaw within the ICQ 99b 1.1.1.1 instant messaging client software. This vulnerability specifically manifests when the client processes malformed URL content embedded within ICQ messages, creating a pathway for remote code execution attacks. The flaw exists in the client-side parsing mechanism that fails to properly validate the length and structure of URL data, allowing attackers to craft malicious messages that can trigger memory corruption when the application attempts to handle the malformed input.
The technical implementation of this vulnerability stems from improper bounds checking within the ICQ client's URL handling routine. When a user receives an ICQ message containing a specially crafted URL, the client's buffer management fails to enforce size limitations on the URL string, leading to a classic stack-based buffer overflow condition. This condition occurs because the application writes more data into a fixed-size buffer than it can accommodate, causing adjacent memory locations to be overwritten with attacker-controlled data. The overflow typically corrupts the return address on the stack, allowing an attacker to redirect execution flow to malicious code injected into the buffer.
The operational impact of this vulnerability extends beyond simple remote code execution, as it provides attackers with complete control over the affected system. An attacker positioned to send malicious ICQ messages to a target can potentially execute arbitrary commands with the privileges of the user running the ICQ client. This creates a significant risk for users who may receive messages from untrusted sources, particularly in enterprise environments where ICQ clients might be used for business communications. The vulnerability is particularly dangerous because it requires minimal interaction from the user beyond simply receiving and potentially clicking on the malformed URL, making it an effective vector for social engineering attacks.
From a cybersecurity framework perspective, this vulnerability maps directly to CWE-121, which describes stack-based buffer overflow conditions, and aligns with ATT&CK technique T1203, which covers legitimate program execution through user interaction. The vulnerability also demonstrates characteristics consistent with the broader category of privilege escalation attacks, as the successful exploitation typically results in system compromise with the user's privileges. Security practitioners should note that this vulnerability was particularly significant in the early 2000s when instant messaging platforms were widely adopted, as it highlighted the security risks inherent in client-side applications that process untrusted network data. The exploitation of such vulnerabilities often requires careful crafting of the malicious payload to ensure successful stack manipulation and execution control.
Mitigation strategies for this vulnerability primarily focus on immediate software updates and patches provided by the vendor. Users should ensure they are running the latest version of the ICQ client that addresses this specific buffer overflow issue through proper input validation and bounds checking. Network administrators should consider implementing message filtering mechanisms that can identify and block potentially malicious ICQ messages containing malformed URLs. Additionally, user education regarding the dangers of clicking on suspicious links in instant messaging applications remains crucial. The vulnerability also underscores the importance of secure coding practices, particularly around buffer management and input validation, which should be implemented as fundamental security controls in all client applications that process network data. Organizations should conduct regular vulnerability assessments to identify similar issues in other instant messaging and communication platforms that may be at risk from similar buffer overflow conditions.