BKDR_DASERF.I
Backdoor:Win32/Daserf.A (Microsoft), a variant of Win32/Agent.NKT trojan (Eset)
Windows 2000, Windows Server 2003, Windows XP (32-bit, 64-bit), Windows Vista (32-bit, 64-bit), Windows 7 (32-bit, 64-bit)
Threat Type: Backdoor
Destructiveness: No
Encrypted:
In the wild: Yes
OVERVIEW
This backdoor arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.
TECHNICAL DETAILS
36,864 bytes
EXE
Yes
08 Mar 2013
Arrival Details
This backdoor arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.
Installation
This backdoor drops the following copies of itself into the affected system:
- %System%\exp1orer.exe
(Note: %System% is the Windows system folder, which is usually C:\Windows\System32.)
It drops the following non-malicious file:
- %System%\usid.dat
- %System%\pinfs.dat
(Note: %System% is the Windows system folder, which is usually C:\Windows\System32.)
Autostart Technique
This backdoor registers as a system service to ensure its automatic execution at every system startup by adding the following registry keys:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\msuwegd
Other Details
This backdoor connects to the following possibly malicious URL:
- http://www.{BLOCKED}k.net/img/addr.gif
SOLUTION
9.300
9.772.06
08 Mar 2013
Step 1
Before doing any scans, Windows XP, Windows Vista, and Windows 7 users must disable System Restore to allow full scanning of their computers.
Step 2
Restart in Safe Mode
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. Before you could do this, you must restart in Safe Mode. For instructions on how to do this, you may refer to this page If the preceding step requires you to restart in safe mode, you may proceed to edit the system registry.
- In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services
- msuwegd
- msuwegd
Step 4
Search and delete these files
- %System%\usid.dat
- %System%\pinfs.dat
Step 5
Restart in normal mode and scan your computer with your Trend Micro product for files detected as BKDR_DASERF.I. 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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