Microsoft Corp. is taking the unusual step of issuing an emergency fix for a security hole in its Internet Explorer software that has exposed millions of users to having their computers taken over by hackers.

    The "zero-day" vulnerability, which came to light last week, allows criminals to take over victims' machines simply by steering them to infected Web sites; users don't have to download anything for their computers to get infected, which makes the flaw in Internet Explorer's programming code so dangerous. Internet Explorer is the world's most widely used Web browser.

    Microsoft said it plans to ship a security update, rated "critical," for the browser on Wednesday. People with the Windows Update feature activated on their computers will get the patch automatically.
Thousands of Web sites already have been compromised by criminals looking to exploit the flaw. The bad guys have loaded malicious code onto those sites that automatically infect visitors' machines if they're using Internet Explorer and haven't employed a complicated series of workarounds that Microsoft has suggested.

    Microsoft said it has seen attacks targeting the flaw only in Internet Explorer 7, the most widely used version, but has cautioned that all other current editions of the browser are vulnerable.

    Microsoft rarely issues security fixes for its software outside of its regular monthly updates. The company last did it in October, and a year and half before that.

    微軟正采取前所未有的針對IE安全漏洞的緊急措施，因為數百萬使用IE瀏覽器的用戶的計算機被黑客控制。

    這個“Zero-day”脆弱性上周剛出現就被不法分子利用，并通過引誘用戶點擊已經感染的Web站點來控制用戶的計算機。用戶不用下載任何文件就會被感染，這樣使得IE漏洞的編程代碼很危險。目前，IE瀏覽器是世界上使用最廣泛的瀏覽器。

    微軟曾計劃在周三發布一個瀏覽器安全更新，定級為“危急”。而設置了Windows自動更新的用戶的計算機將會自動獲得該補丁。

    上千個Web站點已經因為這一違法的利用這個缺陷而受連累。一些不法分子已經在一些網站植入病毒并傳播給訪問的用戶，如果這些用戶使用IE并且沒有遵照微軟承認的一系列復雜的系統環境。

    微軟聲明攻擊的目標只是廣泛使用的IE7，同時警告目前所有其他瀏覽器的版本也是脆弱的。

    微軟在定期的每月更新之外，幾乎很少沒有發布過安全策略，距離此次，最近的也是一年半前的十月。