Threat Level: green Handler on Duty: Brad Duncan

SANS ISC: McAfee 4715 DAT False Positive Deletion Reports Follow-up - SANS Internet Storm Center SANS ISC InfoSec Forums


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McAfee 4715 DAT False Positive Deletion Reports Follow-up
Friday we started receiving reports of file deletion problems from admins using McAfee AV, scans that were using the 4715 DAT's issued Friday were incorrectly identifying many executables as as W95/CTX virus. Portions of the information submitted are excerpted below, and we thank all of the admins who reported the problems which allowed us to get the early problem alert out. Your reports and the Diary warning McAfee/NAI rolls bad pattern helped many admins.

McAfee DAT 4716 corrects the problem, references W95/CTX and says;
"Users who have moved detected files to quarantine should restore them to their original location.  Windows users who have had files deleted should restore files from backup or use System Restore .

Virusscan Online users can restore the falsely detected file from the Manage Quarantined Files.."

ISC participants report excerpts;

"The 4715 dat files are incorrectly identifying multiple different files as being infected with W95/CTX when scanned with the on-demand scanner with the following products:

VirusScan Enterprise 8.0i
VirusScan Enterprise 7.1
VirusScan Enterprise 7.0
Managed VirusScan 4.0
Managed VirusScan 3.5
VirusScan Online 11
VirusScan Online 10
LinuxShield
VirusScan 7.03 (consumer)

At this time you should cancel any scheduled on-demand scans until the release of the 4716 DATs."

"Some example files are graph9.exe and excel.exe from office 2000" "....3700 files have been quarantined on over 100 pcs."

"We think McAfee's latest DAT file may be bad.  They improved the detection for several variants of the W95/CTX virus, and now our scanners are detecting supposedly infected executables all over our network, including on an original Microsoft Office 11 CD.  Our guess is that this is a false positive.  If so, and your readers have quarantine or delete set as the default action, the Virusscan will do more damage than a real virus would."

"attempted to remove files such as Dell OpenManage, Cygwin, perl, Sysinternals pstools suite."

"anything that was in the PATH environment variable was targeted."

"Not only did it attempt to remove files in the %ORACLE_HOME%\bin directory, but also in the .patch_storage folder - so as far as oracle files, this was not limited to the PATH environment variable."

"This was also capable of navigating mapped drives, so if you had a file server setup as a common install location, if filesystem permissions permitted modification of such files, you'll want to refresh the installation files from the downloaded, compressed source file."

"[removed] ShavlikPro (commandline4.exe) and the entire SuperCACLs suite from trustedsystems.com"

"I started getting reports that looked lke a virus outbreak so I forced scans on all the network machines. This turned out to make matters worse because hundreds of files per machine were incorrctly identified as virus infected and quarantined. Many hours will be spent restoring these files from quarantine. Thankfully it was not set to delete the files."

"We had over 3700 quarantine events. I counted 297 individual file names."
Patrick

193 Posts

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