Google has fixed a security flaw in its desktop search software that created a means for hackers to rifle through personal files on users' PCs.

A failure in Google Desktop to "properly encode output containing malicious or unexpected characters" created a means for hackers to cross from the web environment to the desktop application environment.

Because of this, hostile JavaScript code might be used to control Google Desktop functionality, enabling hackers to work around security defences to access confidential desktop files.

The vulnerability opened the way to cross-site scripting attacks which, in turn, created a means for attackers to plant hostile code on targeted machines. Google said that it has no evidence the vulnerability was exploited. An automatic update means that users are protected from attack, AP reports.

The flaw was discovered by web security firm Watchfire, which reported the bug to Google on 4 January. The flaw was fixed on 1 February but news of the bug only emerged this week, coinciding with the release by Watchfire of a press release and research paper (PDF) explaining the problem.

The flaw is far from the first, or no doubt the last, to affect Google's popular desktop search software. Watchfire said that the integration between desktop applications and Web based applications poses a constant risk. ®