Sun Microsystems and BlackBerry maker Research in Motion both had to act yesterday to fix major security problems in their respective products which could have allowed hackers to run unauthorised software on a victim's PC.

Sun's was the larger of the two tasks, patching 12 flaws in its Java Runtime Environment, including one vulnerability which allows "an untrusted Java Web Start application to run as a trusted application and execute arbitrary code".

Java and other third party applications are increasingly being targeted by hackers thanks to large installed base and the fact that Microsoft is getting better at protecting its own software.

RIM, on the other hand, had just the one flaw to patch, releasing a fix for a flaw in the BlackBerry Desktop Manager which could allow remote code execution. The vulnerability was given a CVSS severity rating of 9.3 and applies to BlackBerry Desktop Software version 5.0 and earlier on all platforms, so it warrants immediate attention.