how can I delete an infected file from backup folders

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Level 2

213 points

how can I delete an infected file from backup folders

ran Sophos anti-virus recently and it told me I have a malicious trojan on my Mac, Mal/PDFEx-H (which supposedly only affects windows, but it turned up anyway.) Sophos couldn't remove it automatically, so I was instructed to do a manual removal; however, every time I try to delete the file from the backup folders in which it is located, I get a message that "backup files can't be altered."

so, my question is: how do I get rid of some malicious trojan (even though it's only for windows) from my backup folders? Btw, the backup folders in which it is located are all over 2 years old...don't know if that makes any difference, like maybe the entire folders could be deleted without any adverse effects?

thanks for any advice.

Aluminum iMac, Mac OS X (10.6.8), 1 GB

Posted on Aug 14, 2011 3:47 PM

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Answer 1

Best reply

Csound1

Level 9

59,973 points

Aug 14, 2011 3:49 PM in response to E. Kennedy

Ignore it, it can't run on OSX let alone in backup folders. If you ever need to restore delete it then.

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Answer 2

Linc Davis

Level 10

209,547 points

Aug 14, 2011 4:01 PM in response to E. Kennedy

I assume you're using Time Machine for backup. Enter TM, locate the supposed malware, and select "Remove all backups of this file" from the action menu (gear icon.)

Then uninstall the useless Sophos product.

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Answer 3

E. Kennedy Author

Level 2

213 points

Aug 17, 2011 11:39 AM in response to Csound1

thanks for the info - since it was a windows trojan, I was pretty sure I'd be safe since I only have MacOS on my iMac, but thought I'd better make sure 🙂

thanks for the help!

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Answer 4

E. Kennedy Author

Level 2

213 points

Aug 17, 2011 11:41 AM in response to Linc Davis

thanks for the help!

just wondering why you said that about Sophos? it's a download from Apple's web site and it did catch this, even though it couldn't remove it...

thanks, again!

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Answer 5

Csound1

Level 9

59,973 points

Aug 17, 2011 12:19 PM in response to E. Kennedy

E. Kennedy wrote:

thanks for the help!

just wondering why you said that about Sophos? it's a download from Apple's web site and it did catch this, even though it couldn't remove it...

thanks, again!

I think that Linc means (and I concur) you don't need it to protect your Mac and it wastes resources, if it makes you feel better because it alerts you to windows viruses then remove it and install ClamAX or AV or whetever it's called.

But you don't need AV software.

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Answer 6

Linc Davis

Level 10

209,547 points

Aug 17, 2011 1:35 PM in response to E. Kennedy

The fact that Apple listed Sophos on its site doesn't imply that it's a good product. All commercial "anti-virus" products for the Mac (included the free version of Sophos) are worse than useless. All they can do is cause problems. The Mac OS has built-in detection of known Mac malware in downloaded files, for the little good that does. If you need to detect Windows malware, use ClamXav -- nothing else.

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Answer 7

E. Kennedy Author

Level 2

213 points

Aug 18, 2011 4:32 PM in response to Linc Davis

so, Linc & CSound1, theres NO WAY windows virus/trojan/malware can do any harm to my Mac if I'm just running MacOS? and there aren't any Mac viruses/trojans/malware that can get through the built-in protection you mentioned? if that's the case, then maybe I'll take your advice...gotta do a little more thinking on it first, though, just to assure my paranoid self 🙂 lol

thanks for the help & advice 🙂

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Answer 8

Csound1

Level 9

59,973 points

Aug 18, 2011 4:42 PM in response to E. Kennedy

Windows executable files (.exe) can not run on OSX, doesn't matter if they are viruses or programs, they won't run (or BootCamp would be unnecessary)

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Answer 9

babowa

Level 9

78,109 points

Aug 18, 2011 5:38 PM in response to E. Kennedy

Here is a really good article to read:

http://www.reedcorner.net/guides/macvirus/

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Answer 10

Linc Davis

Level 10

209,547 points

Aug 18, 2011 7:13 PM in response to E. Kennedy

... there aren't any Mac viruses/trojans/malware that can get through the built-in protection you mentioned?

There might be. At some point, there certainly will be, because the malware attackers are always one day ahead of the defenders. There will be malware that no commercial product can detect either. That's why you can't rely on anti-virus software to protect you. You have to follow sound security practices, such as not installing software from a source you can't trust.

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Answer 11

E. Kennedy Author

Level 2

213 points

Aug 19, 2011 4:39 PM in response to babowa

thanks for the link...read it & bookmarked it! 🙂

and thanks, Linc & Csound1, too...I never download or run apps from sources that I don't know, and don't use P2P file sharing, either, so it's a little confusing where this thing came from, and disguised as a .pdf file no less that I don't specifically remember downloading...

thanks, again, to everyone for the help & advice 🙂

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Answer 12

tixrus

Level 1

8 points

Oct 15, 2015 10:11 AM in response to Linc Davis

I had some "viruses" in TM backups. It was crud I don't want anyway. So I tried going into Time Machine and deleting all backups of this file and nothing seemed to happen. When I COULD locate the file it is still there. Then others I couldn't even find in the backup it said.

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