Microsoft's first security patch roundup of 2005 brings with it three security updates, two of which are critical. Most importantly, the software giant (at least partly) fixed a flaw with a HTML Help Control function in Windows, which recently became the target of a readily available exploit.

The security bug creates way for attackers to take complete control of vulnerable systems. Win 2000, Win 2003, NT 4 and XP users - even those who've applied SP2 - need to apply Microsoft's fix (MS05-001). Early reaction has been lukewarm, with security alerting firm Secunia describing it as a partial fix only.

Also on Microsoft's critical list is an Icon and Cursor handling flaw which can be exploited providing vulnerable users are tricked into visiting maliciously constructed websites (MS05-002). A flaw in Windows indexing component rates lower on Microsoft's peril index chiefly because the service is turned off by default. The company says this patch (MS05-003) is "important".

This month's patches are the first to be approved by a "small number of dedicated external evaluation teams", who are members of a closed beta programme for testing security updates. The Security Update Validation Program is designed to make sure software fixes are stable and reliable, an issue that has been a perennial problem for Microsoft shops in the past.

Yesterday also marked the first instalment of technology to remove malicious software from users' systems. The tool will be updated on the second Tuesday of every month. This month's update removes Blaster, Sasser, MyDoom, DoomJuice, Zindos, Berweb (also known as Download.Ject), Gailbot and Nachi viruses/worms. User can download the tool separately here or receive it through Windows Update. ®

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