BKDR_BIFROSE.ZAS
Windows 2000, XP, Server 2003
Threat Type: Backdoor
Destructiveness: No
Encrypted: No
In the wild: Yes
OVERVIEW
This backdoor opens random ports.
It opens a hidden Internet Explorer window.
TECHNICAL DETAILS
86,523 bytes
PE
Yes
08 Sep 2010
Installation
This backdoor drops the following copies of itself into the affected system:
- %WINDOWS%\WinSxS\winsxs.exe
It drops the following files:
- %WINDOWS%\WinSxS\wlog32
- %User Application Data%\settings32.dat
Other System Modifications
This backdoor adds the following registry keys:
HKEY_LOCAL_MACHINE
HKEY_CURRENT_USER\Software\winsxs32
Backdoor Routine
This backdoor opens a random port to allow a remote user to connect to the affected system. Once a successful connection is established, the remote user executes commands on the affected system.
Other Details
This backdoor opens a hidden Internet Explorer window.
SOLUTION
8.900
07.460.06
13 Sep 2010
9/13/2010 12:00:00 AM
Step 1
For Windows XP and Windows Server 2003 users, before doing any scans, please make sure you disable System Restore to allow full scanning of your computer.
Step 2
Search and delete these files
%Windows%\WinSxS\wlog32
%Application Data%\settings32.dat
Step 3
Delete this registry key
Important: Editing the Windows Registry incorrectly can lead to irreversible system malfunction. Please do this step only if you know how or you can ask assistance from your system administrator. Else, check this Microsoft article first before modifying your computer's registry.
- In HKEY_CURRENT_USER\Software
- winsxs32
- winsxs32
- In HKEY_LOCAL_MACHINE\SOFTWARE
- winsxs32
- winsxs32
Step 4
Scan your computer with your Trend Micro product to delete files detected as BKDR_BIFROSE.ZAS. If the detected files have already been cleaned, deleted, or quarantined by your Trend Micro product, no further step is required. You may opt to simply delete the quarantined files. Please check this Knowledge Base page for more information.
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