CVE-2006-5650 in Instant Messenger
Summary
by MITRE
The ICQPhone.SipxPhoneManager ActiveX control in America Online ICQ 5.1 allows remote attackers to download and execute arbitrary code via the DownloadAgent function, as demonstrated using an ICQ avatar.
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Analysis
by VulDB Data Team • 04/26/2026
The vulnerability identified as CVE-2006-5650 represents a critical security flaw in the ICQPhone.SipxPhoneManager ActiveX control bundled with America Online ICQ version 5.1. This ActiveX component was designed to facilitate VoIP communications through the ICQ messaging platform but contained a dangerous implementation flaw that exposed users to remote code execution attacks. The vulnerability specifically resides in the DownloadAgent function which lacks proper input validation and security controls when processing external data sources. Attackers could exploit this weakness by crafting malicious payloads that would be executed automatically when the vulnerable ActiveX control attempted to download and process data from remote sources.
The technical nature of this vulnerability aligns with CWE-74, which describes improper neutralization of special elements in output used by a downstream component, and CWE-94, which covers improper control of generation of code. The attack vector leverages the trust relationship between the ActiveX control and the browser environment, where the control is executed with the privileges of the user running the application. When an attacker creates a malicious ICQ avatar or similar file that triggers the DownloadAgent function, the control downloads and executes arbitrary code from attacker-controlled servers without proper authentication or verification mechanisms. This represents a classic example of a remote code execution vulnerability that can be exploited through social engineering techniques, where users are tricked into downloading and opening malicious content.
The operational impact of this vulnerability extends beyond simple code execution to encompass complete system compromise and potential data exfiltration. Since the ActiveX control operates within the context of the user's browser session, successful exploitation could result in full system access, allowing attackers to install additional malware, modify system configurations, or extract sensitive user information. The vulnerability is particularly dangerous because it requires minimal user interaction beyond viewing or opening a malicious avatar, making it highly effective for mass deployment attacks. Organizations using ICQ 5.1 were particularly at risk, as the vulnerability could be exploited through legitimate messaging channels, making it difficult to detect and prevent.
Mitigation strategies for CVE-2006-5650 should focus on immediate removal of the vulnerable ActiveX control from affected systems, as the vulnerability cannot be patched due to the age of the software and the specific nature of the flaw. Security administrators should implement browser security policies that disable ActiveX controls or restrict their execution to trusted sites only. The use of application whitelisting can also prevent the execution of untrusted ActiveX components, while network-based controls such as firewalls can block connections to known malicious domains. According to ATT&CK framework, this vulnerability maps to T1190 for Exploit Public-Facing Application and T1059 for Command and Scripting Interpreter, as attackers would need to establish command and control channels to deliver and execute malicious payloads. Organizations should also consider implementing network monitoring to detect suspicious download activities and establish incident response procedures for handling potential exploitation attempts. The vulnerability highlights the importance of proper input validation and the dangers of executing untrusted code in privileged contexts, serving as a reminder of the critical need for secure coding practices in software development and the importance of maintaining up-to-date security measures.