Using the freeware version of Bitdefender, I scanned my imac and found several trojans within e-mail attachments (which I had never opened) that had been archived by Time Machine. However, it said it could not remove the malware. Is there a way for me to go into those backups and remove the offending files?
iMac (27-inch Mid 2011), OS X Yosemite (10.10.3), backups stored on external drive
Don't let any other software touch a Time Machine backup to remove anything. Do not manually remove anything from a TM backup. Both are a very good way to screw it up. Since what the AV software found is completely harmless to your Mac, it doesn't matter if they sit on the TM drive. Eventually, as TM needs room for newer items, they will be automatically deleted when they become some of the oldest items.
are they saying you have "mac trojans" or is it showing up as known Windows Trojans, because it might be detecting those but they wont be abel to run on your mac unless you have parallels or boot camp running at the host OS.
They don't say, but the files are labeled as trojans and are exe file attachments. Unfortunately, however, I am running Parallels Desktop on the Mac, so they could do damage to the Windows system if activated. Of course, if I never need to recover a backup, there is no problem. (I have now removed all deleted e-mails from my active Mac system, so the trojans are only in my Time Machine back-ups now.)
if they are .EXE's they wont run or launch on the mac, and even if you did run them in WINE or a DOS emulator they would look for MSWindows specific files to infect but never find them as the don't exist on the mac. Unless you execute them inside your virtualized Windows session they should not be a problem. If you can access those backup emails through parallels sessions and zap them with a Windows AV you might try that , but the Mac anti-virus out there is not very flexible, resource intensive and more trouble than it's worth, that being said you may want to keep whatever anti-virus running and up-to-date on your virtual windows and you should be fine in the unlikely event those files somehow find their way over to that side.
I came to the same conclusion. Since this was showing up on multiple back-ups. I figured there had to be files still on the machine that were getting copied into the back-ups. Looking carefully at the offending files (to the extent I could in the back-ups), I figured out the files were probably old Outlook pst files that I had kept. (I'd stopped using Outlook when I got the mac in 2011.) I checked those files with Bitdefender, and sure enough there were nasty attachments. which bitdefender easily removed. Nevertheless, I decided to take the cleaned-up pst files off the machine and store them on a dvd. As you say, since my back-up drive isn't huge, the back-ups with the malware in them should be deleted shortly. It is puzzling, though, that Bitdefender didn't find the original files until I scanned them specifically. I guess that's the shortcoming of free versions.
unfortunately!!!
Before to scan my last backup, I already scanned my HD with El Capitan,
Bitfender found few different malwares which were removed.
then I decided to scan the whole backup disk.
Bitfender detected several malwares 😕, but failed remove or to put in qarantine 🙂. Nevertheless, I wanted. 😟
I look at the help nothing about backups was mentions. 😝 I got the clever idea to tag 2 of them from the most recent backup (2nd nov 2015).
In order to succeed, I entered admin pass and tagged the concerned folder and the file.
Now the files are tagged, 😟 and I just read about this thread in the forum.
What is strange:
How come Bitfender didn't detect those same malwares which are on my actual HD?
I am removing those files manually using their respective path detected by Bitfender on my last backup.
Shall I continue the removal and then BackUp?
The key question:
Does it exist an antivirus which is doing the job properly?
Thank you.
PS/ sorry I might not be on the right community but my backups are with OS X Yosemite.
OS X El Capitan v 11.10.1
Bitfender Version 3.5 (3.5.9165)
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It's entirely possible (and likely) Bitdefender is reporting false positives. That, and all AV software on a Mac is a complete waste of time and system resources. There are no viruses for OS X and never have been. All current attacks are in the form of Trojans (something you have to be tricked into installing). The only kind of actual virus Bitdefender may find would be for Windows only, which would almost always be an email attachment on a Mac. Can't do a thing to your system, but at least flags something you wouldn't want to forward to Windows users.
removing a virus from a time machine backup
