Security experts are expressing concern at Microsoft's failure to patch a flaw in PowerPoint that is already being exploited by malware writers.

Many were expecting a patch as part of the last Patch Tuesday but to date there has been no sign of the fix.

“This PowerPoint exploit is in the wild right now,” said Graham Cluley, senior technology consultant at Sophos. “It comes in the form of a presentation showing naked Japanese girls bathing in rockpools, or as an IQ test, to lure the user in. We're hoping Microsoft will patch this soon.”

He said that so far the exploit was being used in a targeted fashion but there was serious concern that it would be spammed out as part of a botnet recruitment drive.

The issue comes as more and more security experts are expressing concern at the levels of application vulnerabilities and the lack of patching and updating.

“It's a problem for IT departments as they are often stretched for resources and there are many applications to patch,” said Niels Henrik Rasmussen, founder of vulnerability researcher Secunia.

He pointed out that both his own research and the latest Microsoft Security Intelligence Report showed that application flaws were becoming a more pressing security issue than operating system flaws.