Remortgages

IIS 5 Web Server Compromises

added June 24 | updated July 2

US-CERT is aware of activity affecting compromised web sites running Microsoft's Internet Information Server (IIS) 5 and end-user systems that visit these sites.
IIS Web Servers
Compromised sites are appending JavaScript to the bottom of web pages. Web server administrators running IIS 5 should verify that there is no unusual JavaScript appended to the bottom of pages delivered by their web server.

End-User Systems
When an end-user visits a web site that has been compromised, this JavaScript attempts to access a file hosted on another server. This file may contain malicious code that can affect the end-user's system.

This activity is another example of why end users must exercise caution when JavaScript is enabled in their web browser. Disabling JavaScript will prevent this activity from affecting an end-user's system, but may also degrade the appearance and functionality of some web sites that rely upon JavaScript. US-CERT recommends that end-users disable JavaScript unless it is absolutely necessary. Users should be aware that any web site, even those that may be trusted by the user, may be affected by this activity and thus contain potentially malicious code.

Microsoft has released an important security update for Internet Explorer (IE). This update reduces the impact of attacks against several vulnerabilities in IE. For additional information, please refer to TA04-184A and VU#713878 at http://www.us-cert.gov/current/

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