BKDR_NUPIC.AB
Backdoor:Win32/Nupic.A (Microsoft); Trojan.Gen (Symantec); BehavesLike.Win32.Malware.wsc (mx-v) (Sunbelt)
Windows 2000, Windows XP, Windows Server 2003
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
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:
- %Windows%\wxpob.exe
(Note: %Windows% is the Windows folder, which is usually C:\Windows or C:\WINNT.)
Autostart Technique
This backdoor adds the following registry entries to enable its automatic execution at every system startup:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Active Setup\Installed Components\{AF5F11D4-F6D4-4c5e-9130-72187BE710AC}
StubPath = "%Windows%\wxpob.exe"
Other System Modifications
This backdoor adds the following registry keys:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Active Setup\Installed Components\{AF5F11D4-F6D4-4c5e-9130-72187BE710AC}
It deletes the following registry keys:
HKEY_CURRENT_USER\SOFTWARE\Microsoft\
Active Setup\Installed Components\{AF5F11D4-F6D4-4c5e-9130-72187BE710AC}
Dropping Routine
This backdoor drops the following files:
- %Windows%\wshinp.dll
(Note: %Windows% is the Windows folder, which is usually C:\Windows or C:\WINNT.)
This report is generated via an automated analysis system.
SOLUTION
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
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.
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Active Setup\Installed Components
- {AF5F11D4-F6D4-4c5e-9130-72187BE710AC}
Step 4
Delete this registry value
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_LOCAL_MACHINE\SOFTWARE\Microsoft\Active Setup\Installed Components\{AF5F11D4-F6D4-4c5e-9130-72187BE710AC}
- StubPath = "%Windows%\wxpob.exe"
Step 5
Search and delete this file
- %Windows%\wshinp.dll
Step 6
Restart in normal mode and scan your computer with your Trend Micro product for files detected as BKDR_NUPIC.AB. 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.
Step 7
Restore these deleted registry keys/values from backup
*Note: Only Microsoft-related keys/values will be restored. If the malware/grayware also deleted registry keys/values related to programs that are not from Microsoft, please reinstall those programs on your computer.
- In HKEY_CURRENT_USER\SOFTWARE\Microsoft\Active Setup\Installed Components
- {AF5F11D4-F6D4-4c5e-9130-72187BE710AC}
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