August 12, 2008
Microsoft Windows Messenger is prone to an information-disclosure vulnerability. An attacker can exploit this issue by enticing an unsuspecting victim to visit a malicious HTML page. Successfully exploiting this issue allows remote attackers to obtain sensitive information that may aid in further attacks.
- Microsoft Windows Messenger 4.7
- Microsoft Windows Messenger 5.1
Run all software as a nonprivileged user with minimal access rights.
To reduce the impact of latent vulnerabilities, always run nonadministrative software as an unprivileged user with minimal access rights.
Do not follow links provided by unknown or untrusted sources.
To reduce the likelihood of successful attacks, never follow links provided by unknown or untrusted individuals.
Set web browser security to disable the execution of script code or active content.
Since a successful exploit of this issue allows malicious code to execute in web clients, consider disabling support for script code and active content within the client browser. Note that this mitigation tactic might adversely affect legitimate websites that rely on the execution of browser-based script code.
Review and adjust according to policy any default configuration settings.
To mitigate the possibility of an exploit through HTML email, configure email clients to render messages in plain text. This mitigation may adversely affect some functionality of email clients.
The vendor has released updates and an advisory. Please see the references for more information.
Haifei Li (cocoruder) of the Fortinet Security Research Team
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