Micro-blogging site Twitter has begun filtering links to known malware sites.
The tactic, noticed by security researchers on Monday but yet to be officially announced by Twitter, is designed to prevent surfers straying onto sites packed with dangerous exploits.
Adoption of the approach follows the increased targeting of Twitter by worms, spam and account hijacking attacks over recent weeks. The widespread use of URL shortening in Twitter messages (which can be no longer than 140 characters) makes it easy to hide the true destination of links.
A blog posting by Mikko Hypponen of F-Secure explains how surfers are served up a warning message when they attempt to follow a link from Twitter towards a known bad site.
Costin Raiu, a security researcher at Kaspersky Lab, adds that Twitter appears to be using Google's Safe Browsing API. "It won't catch everything but is definitively a step forward," he adds. ®