Microsoft plans to release a software tool to clean computers infected by a Trojan horse program linked to recent, widespread web-based attacks on Windows users.
Mike Nash, Microsoft's corporate vice-president for the Security Business and Technology Unit said that the company would publish a cleaner tool next week for the Trojan, known as Download.Ject or Scob.
Nash said the company's decision to release cleaner tools for viruses including Blaster, MyDoom and Sasser was part of a commitment to provide "authoritative information and guidance" to customers about security issues.
The software programs scan Windows systems for signs of a virus, such as configuration changes or files associated with infection. Customers can then click a button to remove the infection from their Windows system.
Previous cleanup tools, which Microsoft distributes for free from its web page, have been popular with users. Millions of copies of both the Blaster and Sasser removal tools have been downloaded.
Nash said that roughly 40 million Microsoft customers have used the tools since the Blaster removal tool was released in January.
The creation of a Download.Ject removal tool is just the latest step by Microsoft to try to counter the effects of widespread web-based attacks that use flaws in the Internet Information Server (IIS) web server and Internet Explorer web browser to plant a Trojan on vulnerable Windows systems.
The attacks, which were first spotted in June, were attributed to a Russian criminal hacking group called the Hangup Team.
Companies that failed to apply a recent software patch for Microsoft's IIS Version 5.0 web server fell victim to the attacks, in which hackers modified the configuration of IIS servers, allowing malicious code to be appended to every HTML document served from the compromised websites.
Two vulnerabilities in Windows and the IE web browser enabled attackers to silently run the malicious code on machines that visited the compromised sites, redirecting the customers to now-dormant web sites controlled by the hackers. While the user was on the website, a Trojan horse program was downloaded and installed on the customer's system and captured sensitive information, such as account numbers, user names and passwords.
On 2 July, Microsoft announced changes that alter the configuration of its Windows 2000, XP and Windows Server 2003 operating systems to help customers fight off the attack. It disabled a Windows component called ADODB.Stream, which online criminals used to copy malicious code onto Windows users' machines.
Paul Roberts writes for IDG News Service