TROJ_AGENT.DVAB
PWS:Win32/Zbot.PK (Microsoft); Trojan Horse (Symantec); Worm.Win32.Pinit.gen (Kaspersky); Trojan.Generic.1808753 (FSecure)
Windows 2000, XP, Server 2003
![](/vinfo/imgFiles/legend.jpg)
Threat Type: Trojan
Destructiveness: No
Encrypted:
In the wild: Yes
OVERVIEW
This Trojan 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 Trojan 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 Trojan drops the following copies of itself into the affected system:
- %System%\ntos.exe
(Note: %System% is the Windows system folder, which is usually C:\Windows\System on Windows 98 and ME, C:\WINNT\System32 on Windows NT and 2000, or C:\Windows\System32 on Windows XP and Server 2003.)
It creates the following folders:
- %System%\wsnpoem
(Note: %System% is the Windows system folder, which is usually C:\Windows\System on Windows 98 and ME, C:\WINNT\System32 on Windows NT and 2000, or C:\Windows\System32 on Windows XP and Server 2003.)
Autostart Technique
This Trojan modifies the following registry entries to ensure it automatic execution at every system startup:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Winlogon
userinit = "%System%\userinit.exe,%System%\ntos.exe,"
(Note: The default value data of the said registry entry is %System%\userinit.exe,.)
Other System Modifications
This Trojan deletes the following files:
- %System%\ntos.exe
- %System%\wsnpoem\video.dll.cla
(Note: %System% is the Windows system folder, which is usually C:\Windows\System on Windows 98 and ME, C:\WINNT\System32 on Windows NT and 2000, or C:\Windows\System32 on Windows XP and Server 2003.)
It adds the following registry entries:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Network
UID = "BRIAN-3D53544FA_00007985"
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer
{F710FA10-2031-3106-8872-93A2B5C5C620} = {random values}
HKEY_CURRENT_USER\Software\Microsoft\
Windows NT\CurrentVersion\Network
UID = "BRIAN-3D53544FA_0000BCD7"
HKEY_CURRENT_USER\Software\Microsoft\
Windows NT\CurrentVersion\Network
UID = "BRIAN-3D53544FA_0000EE86"
Dropping Routine
This Trojan drops the following files:
- %System%\wsnpoem\video.dll.cla
(Note: %System% is the Windows system folder, which is usually C:\Windows\System on Windows 98 and ME, C:\WINNT\System32 on Windows NT and 2000, or C:\Windows\System32 on Windows XP and Server 2003.)
Other Details
This Trojan connects to the following possibly malicious URL:
- http://{BLOCKED}r.com/z/cfg.bin
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
Identify and delete files detected as TROJ_AGENT.DVAB using either the Startup Disk or Recovery Console
Step 3
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\Windows NT\CurrentVersion\Network
- UID="BRIAN-3D53544FA_00007985"
- In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer
- {F710FA10-2031-3106-8872-93A2B5C5C620}={random values}
- In HKEY_CURRENT_USER\Software\Microsoft\Windows NT\CurrentVersion\Network
- UID="BRIAN-3D53544FA_0000BCD7"
- In HKEY_CURRENT_USER\Software\Microsoft\Windows NT\CurrentVersion\Network
- UID="BRIAN-3D53544FA_0000EE86"
Step 4
Restore this modified 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\Windows NT\CurrentVersion\Winlogon
- From: userinit="%System%\userinit.exe,%System%\ntos.exe,"
To: userinit=%System%\userinit.exe,
- From: userinit="%System%\userinit.exe,%System%\ntos.exe,"
Step 5
Search and delete this folder
Step 6
Search and delete this file
Step 7
Scan your computer with your Trend Micro product to delete files detected as TROJ_AGENT.DVAB. 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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