TROJ_ZLOB.DOT
TrojanDownloader:Win32/Zlob.gen!N (Microsoft); Trojan.Zlob (Symantec); Trojan-Downloader.Win32.Zlob.cee (Kaspersky); Trojan.Win32.Generic.pak!cobra (Sunbelt); Trojan.Downloader.Zlob.AAIP (FSecure)
Windows 2000, Windows XP, Windows 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
110,866 bytes
EXE
No
16 Nov 2012
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 creates the following folders:
- %Program Files%\VideoAccessCodec
- %System Root%\DOCUME~1
- %System Root%\DOCUME~1\ADMINI~1
- %User Profile%\LOCALS~1
- %User Temp%\nsl3.tmp
(Note: %Program Files% is the default Program Files folder, usually C:\Program Files.. %System Root% is the root folder, which is usually C:\. It is also where the operating system is located.. %User Profile% is the current user's profile folder, which is usually C:\Windows\Profiles\{user name} on Windows 98 and ME, C:\WINNT\Profiles\{user name} on Windows NT, and C:\Documents and Settings\{user name} on Windows 2000, XP, and Server 2003.. %User Temp% is the current user's Temp folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, XP, and Server 2003.)
Other System Modifications
This Trojan deletes the following files:
- %User Temp%\nsm1.tmp
- %User Temp%\nsl3.tmp
- %Windows%\SoftwareDistribution\DataStore\Logs\edbtmp.log
(Note: %User Temp% is the current user's Temp folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, XP, and Server 2003.. %Windows% is the Windows folder, which is usually C:\Windows or C:\WINNT.)
It adds the following registry keys:
HKEY_LOCAL_MACHINE\Software\Microsoft\
VideoPlugin
It adds the following registry entries:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
VideoPlugin
pn = "0"
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
VideoPlugin
sid = "502"
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
VideoPlugin
aid = "376"
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
VideoPlugin
said = "0"
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Tracing\
Microsoft\BITS
LogSessionName = "stdout"
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Tracing\
Microsoft\BITS
Active = "1"
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Tracing\
Microsoft\BITS
ControlFlags = "1"
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Tracing\
Microsoft\BITS\CtlGuid
Guid = "4a8aaa94-cfc4-46a7-8e4e-17bc45608f0a"
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Tracing\
Microsoft\BITS\CtlGuid
BitNames = "{random characters}"
Dropping Routine
This Trojan drops the following files:
- %User Temp%\nsb2.tmp
- %Program Files%\VideoAccessCodec\install.ico
- %User Temp%\nsl3.tmp\System.dll
- %Program Files%\VideoAccessCodec\vpncore.exe
- %Program Files%\VideoAccessCodec\imex.bat
- %User Temp%\nsl3.tmp\NSISdl.dll
- %Program Files%\VideoAccessCodec\VideoAccessCodec.ocx
(Note: %User Temp% is the current user's Temp folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, XP, and Server 2003.. %Program Files% is the default Program Files folder, usually C:\Program Files.)
Other Details
This Trojan connects to the following possibly malicious URL:
- http://{BLOCKED}etwork.com/dw.php?{random characters}
This report is generated via an automated analysis system.
SOLUTION
9.300
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
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
- VideoPlugin
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\VideoPlugin
- pn = "0"
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\VideoPlugin
- sid = "502"
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\VideoPlugin
- aid = "376"
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\VideoPlugin
- said = "0"
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Tracing\Microsoft\BITS
- LogSessionName = "stdout"
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Tracing\Microsoft\BITS
- Active = "1"
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Tracing\Microsoft\BITS
- ControlFlags = "1"
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Tracing\Microsoft\BITS\CtlGuid
- Guid = "4a8aaa94-cfc4-46a7-8e4e-17bc45608f0a"
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Tracing\Microsoft\BITS\CtlGuid
- BitNames = "{random characters}"
Step 4
Search and delete these files
- %User Temp%\nsb2.tmp
- %Program Files%\VideoAccessCodec\install.ico
- %User Temp%\nsl3.tmp\System.dll
- %Program Files%\VideoAccessCodec\vpncore.exe
- %Program Files%\VideoAccessCodec\imex.bat
- %User Temp%\nsl3.tmp\NSISdl.dll
- %Program Files%\VideoAccessCodec\VideoAccessCodec.ocx
Step 5
Search and delete these folders
- %Program Files%\VideoAccessCodec
- %System Root%\DOCUME~1
- %System Root%\DOCUME~1\ADMINI~1
- %User Profile%\LOCALS~1
- %User Temp%\nsl3.tmp
Step 6
Scan your computer with your Trend Micro product to delete files detected as TROJ_ZLOB.DOT. 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 this file from backup only Microsoft-related files will be restored. If this malware/grayware also deleted files related to programs that are not from Microsoft, please reinstall those programs on you computer again.
- %User Temp%\nsm1.tmp
- %User Temp%\nsl3.tmp
- %Windows%\SoftwareDistribution\DataStore\Logs\edbtmp.log
Did this description help? Tell us how we did.