Sudden appearance of viruses in 4 year old files including backups
This is somewhat perplexing; this morning I found the last scheduled full backup had failed with error code 0x81000037. A quick Google search revealed that particular failure occurs when a virus not previously detected is detected within a file during the backup process. A full system scan was recommended to clear out any viruses before restarting the backup.
Quick scans are performed frequently and all downloaded files are scanned on download but it's been over a year since I ran a full system scan so it was certainly overdue. The full system scan took 14 hours (it also scanned all the backup sets in the backup drive - 11 of them) and it found 89 security risks of which 67 were resolved and 22 remain unresolved.
- 19 Tracking Cookies - all deleted.
- 5 Trojan.Gen.2 - (virus) - quarantined - in what I think were very old (15 to 20 years maybe) Macromedia flash .exe files, some zipped in archived folders.
- 26 more of Trojan.Gen.2 - (virus) - quarantined - files not disclosed, maybe because they are under another account.
- 1 of Heur.AdvML.B - (heurustic) - quarantined - in an old left over Adobe Flash player installation file
- 11 more of Heur.AdvML.B - (heurustic) - quarantined - files not disclosed, maybe because they are under another account.
- 3 of Heur.AdvML.C - (heuristic) - quarantined - in AutoHotKey installation zip files
- 1 of w32.SillyFDC - (virus) quarantined - file not disclosed, maybe because it's under another account.
- 1 of PUA.Driverdoc - (security risk) - removed - a deleted file that was still in the recycle bin
- 1 of PUA.Maltrec!cg1 - (security risk) - removed - in the same recycle bin file as PUA.Driverdoc
Both PUA security risks were counted together as only one security risk in the tallies.
Unresolved (requiring attention):
22 Heuristic viruses detected in compressed system backup files - 2 files in each of 11 backup sets.
Presumably these remain unresolved as files cannot be removed individually from backup sets without corrupting the backup. These backup sets go back 4 & 1/2 years. I suspect these may all be in the AutoHotKey installation/bin files; 2 in each backup set since I first downloaded and installed AutoHotKey.
Norton Anti Virus's solution is to have me agree to delete the 11 backup sets in their entirety. That's not what I'd call a desirable way to fix the problem.
A full system scan has been performed many times over the past 4 and 1/2 years without these viruses being detected. They can't all be recent infections because two of them were detected in each of the backup sets going back over 4 years.
My Questions are:
- Has anyone else had this problem?
- Are they really viruses or are they false detections?
- Are the old Macromedia flash videos infected or are they coming up as false positives because of their age?
- Is the old Adobe Flash installation file infected or is it again just it's age? Not that I will ever use it anyway.
- Is AutoHotKey (AHK) being falsely flagged as infected by the heuristic screen? Why?
- Is there any way of deleting the two infected files from the system backup sets without losing everything else? If not I really need to now if AutoHotKey has been false flagged as infected before I take such a drastic step.
Thanks in advance for advice or insight anyone can give.