A newly uncovered attack specifically targeting out-of-support Windows XP machines running Internet Explorer 8 is being used to hack potential victims in multiple industries across Europe and North America, according to security researchers.

This is the first “in the wild” attack spotted against Windows XP after Microsoft pulled the life support last month. It was severe enough to prompt Redmond into releasing an emergency, unscheduled patch on Thursday.

The same MS14-021 bulletin also covers critical patches for multiple versions of Windows (including Windows 7 and 8) and the latest versions of IE, so it's not just a problem for those running legacy software.

According to security firm FireEye, multiple hacking crews are using the vulnerability to target government and energy sector organisations in the US and Europe. Firms in finance and defence are also in the firing line of attacks based an the vulnerability.

"We have seen multiple threat actor groups are now adopting this exploit," a FireEye spokeswoman explained.

FireEye initially said the vulnerability affects IE6 through IE11, but the attack is targeting IE9 through IE11, and noted that the approach circumvented Redmond's built-in security preventions (ASLR and DEP) when it first warned about the flaw on 26 April.

It only mentioned the Windows XP element to these so-called "Operation Clandestine Fox" attacks after MS released the emergency fix on 1 May.

Despite its undead status many organisations still make heavy use of Windows XP in their computing infrastructures. For example, an estimated three quarters of UK businesses are still running XP despite the end of XP support. ®