Keep a closer eye on your email. Hackers are sending out messages that appear to come from security firm Symantec. But in reality, they’re so-called "Nitro attacks," aimed at getting administrator credentials and letting the bad guys into your servers. Infoworld reports the emails come with a warning about malware called Poison Ivy. They have an attachment that’s supposed to fix the problem, but it’s actually a malicious file.The hackers also try to fool you, by attaching a copy of Symantec’s report about the malware.