Recent attacks targeted on Google and other companies were possible due to a previously unknown security hole in MS Internet Explorer. Affected are all versions, from IE 6 to IE8.
The really bad thing: This exploit is now in the public.
Microsoft is working on a patch that shall be released as soon as possible.
The german “Bundesamt fÃ¼r Sicherheit in der Informationstechnik” (Federal Office for Security in Information Technology) advises to not use MSIE until a patch is available and deployed.
BSI Press release: https://www.bsi.bund.de/cln_174/ContentBSI/presse/Pressemitteilungen/Sicherheitsluecke_IE_150110.html (in German)