You will not be getting malware from Firefox. Firefox will be getting Malware from your computer or the sites you visit. I was not aware Process Explorer detected malware although obviously it is an aid used to select files to remove and identify suspicious activity. I note from this article that this sort of trojan could apparently hide in Windows System files * http://securityresponse.symantec.com/security_response/detected_writeup.jsp?name=Trojan.Gen.3&vid=42597 I suggest you scan with multiple and up to date tools as suggested in * [[Troubleshoot Firefox issues caused by malware]] The article also lists security fora for obtaining further advice if required. ** including https://forums.malwarebytes.org/index.php?/forum/108-malware-removal-support/