TROJ_PIDIEF.WM is a malicious Trojan which causes problems for PC users once active on a targeted system. TROJ_PIDIEF.WM uses social engineering methods to lure users into performing certain actions that may, directly or indirectly, cause malicious routines to be performed. TROJ_PIDIEF.WM takes advantage of a vulnerability in Adobe Reader and Acrobat and should be removed from the system immediately. Once the vulnerability is successfully exploited, attackers could make unauthorized cross-domain requests from the affected system.