BKDR_ZEGOST.YNPR
Backdoor:Win32/Zegost.BW (Microsoft); RDN/Generic BackDoor!bbm (McAfee); Backdoor.Trojan (Symantec); HEUR:Trojan.Win32.Generic (Kaspersky); Trojan.Win32.Generic!BT (Sunbelt); Trojan horse Dropper.Generic8.SHN (AVG)
Windows
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
380,416 bytes
EXE
Yes
07 Mar 2015
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 creates the following folders:
- %System Root%\DOCUME~1
- %System Root%\DOCUME~1\Wilbert
- %User Profile%\LOCALS~1
(Note: %System Root% is the Windows root folder, where it usually is C:\ on all Windows operating system versions.. %User Profile% is the current user's profile folder, which is usually C:\Documents and Settings\{user name} on Windows 2000, XP, and Server 2003, or C:\Users\{user name} on Windows Vista and 7.)
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\DogKiller
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\NetMan1\Parameters
Other System Modifications
This backdoor deletes the following files:
- %User Temp%\DogKiller.sys
(Note: %User Temp% is the user's temporary folder, where it usually is C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Local\Temp on Windows Vista (32- and 64-bit), Windows 7 (32- and 64-bit), Windows 8 (32- and 64-bit), Windows 8.1 (32- and 64-bit), Windows Server 2008, and Windows Server 2012.)
It adds the following registry entries:
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\DogKiller
Type = "1"
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\DogKiller
ErrorControl = "1"
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\DogKiller
Start = "3"
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\NetMan1
Description = "Power"
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\NetMan1\Parameters
ServiceDll = "%Program Files%\Power.dll"
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\NetMan1
InstallModule = "%User Temp%\new.exe"
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\netscvre
Description = "NT LM Security Support Providers"
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\NetMan1
Type = "12"
It modifies the following registry entries:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\SvcHost
netsvcs = "{random characters}"
(Note: The default value data of the said registry entry is {random values}.)
Dropping Routine
This backdoor drops the following files:
- %User Temp%\zhunquel.exe
- %User Temp%\new.exe
- %User Temp%\sxc.exe
- %User Temp%\91156_cc.TEMP
- gei33.dll
- %Windows%\svchoost.exe
- %System%\pchjco.exe
- %User Profile%\{AC76BA86-7AD7-1033-7B44-AA0000000001}\lpk.dll
- %User Temp%\lpk.dll
- %Program Files%\Adobe\Reader 10.0\Reader\lpk.dll
- %Program Files%\Common Files\Adobe\ARM\1.0\lpk.dll
- %Program Files%\Common Files\Microsoft Shared\DW\lpk.dll
- %Program Files%\Common Files\Microsoft Shared\MSInfo\lpk.dll
- %Program Files%\Common Files\Microsoft Shared\Speech\lpk.dll
- %Program Files%\Internet Explorer\Connection Wizard\lpk.dll
- %Program Files%\Internet Explorer\lpk.dll
- %Program Files%\Messenger\lpk.dll
- %Program Files%\Movie Maker\lpk.dll
- %Program Files%\MSN\MSNCoreFiles\Install\MSN9Components\lpk.dll
- %Program Files%\MSN\MSNCoreFiles\Install\lpk.dll
- %Program Files%\MSN Gaming Zone\Windows\lpk.dll
- %Program Files%\NetMeeting\lpk.dll
- %Program Files%\Outlook Express\lpk.dll
- %Program Files%\Windows Media Player\lpk.dll
- %Program Files%\Windows NT\Accessories\lpk.dll
- %Program Files%\Windows NT\lpk.dll
- %Program Files%\Windows NT\Pinball\lpk.dll
- %Program Files%\WinPcap\lpk.dll
- %Windows%\$MSI31Uninstall_KB893803v2$\lpk.dll
- %Windows%\$MSI31Uninstall_KB893803v2$\spuninst\lpk.dll
- %Windows%\$NtUninstallWIC$\spuninst\lpk.dll
- %Windows%\assembly\NativeImages_v2.0.50727_32\ComSvcConfig\bb3c2f59a821abc54f420f3a9e051d6a\lpk.dll
- %Windows%\assembly\NativeImages_v2.0.50727_32\dfsvc\837fe02bdcf637d5bf1e5ffb935ebb80\lpk.dll
- %Windows%\assembly\NativeImages_v2.0.50727_32\MSBuild\aa99ebdd26e5d493fec18b1714458782\lpk.dll
- %Windows%\assembly\NativeImages_v2.0.50727_32\PresentationFontCac#\4ce7fd62d4107fbe996ab305eb21ee6a\lpk.dll
- %Windows%\assembly\NativeImages_v2.0.50727_32\ServiceModelReg\feac66e81309d67b48f7a9f4cb98f7c8\lpk.dll
- %Windows%\assembly\NativeImages_v2.0.50727_32\SMSvcHost\a098c66aa40d958878f3f5344e6ae1a4\lpk.dll
- %Windows%\assembly\NativeImages_v2.0.50727_32\WsatConfig\13f498f606b7cb97c086eea149b8c872\lpk.dll
- %Windows%\assembly\NativeImages_v4.0.30319_32\ComSvcConfig\51819c709096229ee187a7feee395d9f\lpk.dll
- %Windows%\assembly\NativeImages_v4.0.30319_32\dfsvc\b9b6069e6da06eb57e89cc544397f735\lpk.dll
- %Windows%\assembly\NativeImages_v4.0.30319_32\Microsoft.Workflow.#\6a8da5dd61b1fcfed27f84047a3e2bad\lpk.dll
- %Windows%\assembly\NativeImages_v4.0.30319_32\MSBuild\aa25092606e5e9826db7a7bd0adb9b2b\lpk.dll
- %Windows%\assembly\NativeImages_v4.0.30319_32\SMSvcHost\38f0d77629891e7808424103aaef0728\lpk.dll
- %Windows%\assembly\NativeImages_v4.0.30319_32\WsatConfig\3c0d21e75c9a48aba6fba3ddff0fcf39\lpk.dll
- %Windows%\lpk.dll
(Note: %User Temp% is the user's temporary folder, where it usually is C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Local\Temp on Windows Vista (32- and 64-bit), Windows 7 (32- and 64-bit), Windows 8 (32- and 64-bit), Windows 8.1 (32- and 64-bit), Windows Server 2008, and Windows Server 2012.. %Windows% is the Windows folder, where it usually is C:\Windows on all Windows operating system versions.. %System% is the Windows system folder, where it usually is C:\Windows\System32 on all Windows operating system versions.. %User Profile% is the current user's profile folder, which is usually C:\Documents and Settings\{user name} on Windows 2000, XP, and Server 2003, or C:\Users\{user name} on Windows Vista and 7.. %Program Files% is the Program Files folder, where it usually is C:\Program Files on all Windows operating system versions; C:\Program Files (x86) for 32-bit applications running on Windows 64-bit operating systems.)
Other Details
This backdoor connects to the following possibly malicious URL:
- {BLOCKED}0
- {BLOCKED}5.205.195
This report is generated via an automated analysis system.
SOLUTION
9.700
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.
- In HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services
- DogKiller
- In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\NetMan1
- Parameters
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\SYSTEM\ControlSet001\Services\DogKiller
- Type = "1"
- In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\DogKiller
- ErrorControl = "1"
- In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\DogKiller
- Start = "3"
- In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\NetMan1
- Description = "Power"
- In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\NetMan1\Parameters
- ServiceDll = "%Program Files%\Power.dll"
- In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\NetMan1
- InstallModule = "%User Temp%\new.exe"
- In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\netscvre
- Description = "NT LM Security Support Providers"
- In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\NetMan1
- Type = "12"
Step 5
Restore these modified registry values
Important:Editing the Windows Registry incorrectly can lead to irreversible system malfunction. Please do this only if you know how to or you can seek your system administrator's help. You may also check out this Microsoft article first before modifying your computer's registry.
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\SvcHost
- From: netsvcs = "{random characters}"
To: netsvcs = ""{random values}""
- From: netsvcs = "{random characters}"
Step 6
Search and delete these components
- %User Temp%\zhunquel.exe
- %User Temp%\new.exe
- %User Temp%\sxc.exe
- %User Temp%\91156_cc.TEMP
- gei33.dll
- %Windows%\svchoost.exe
- %System%\pchjco.exe
- %User Profile%\{AC76BA86-7AD7-1033-7B44-AA0000000001}\lpk.dll
- %User Temp%\lpk.dll
- %Program Files%\Adobe\Reader 10.0\Reader\lpk.dll
- %Program Files%\Common Files\Adobe\ARM\1.0\lpk.dll
- %Program Files%\Common Files\Microsoft Shared\DW\lpk.dll
- %Program Files%\Common Files\Microsoft Shared\MSInfo\lpk.dll
- %Program Files%\Common Files\Microsoft Shared\Speech\lpk.dll
- %Program Files%\Internet Explorer\Connection Wizard\lpk.dll
- %Program Files%\Internet Explorer\lpk.dll
- %Program Files%\Messenger\lpk.dll
- %Program Files%\Movie Maker\lpk.dll
- %Program Files%\MSN\MSNCoreFiles\Install\MSN9Components\lpk.dll
- %Program Files%\MSN\MSNCoreFiles\Install\lpk.dll
- %Program Files%\MSN Gaming Zone\Windows\lpk.dll
- %Program Files%\NetMeeting\lpk.dll
- %Program Files%\Outlook Express\lpk.dll
- %Program Files%\Windows Media Player\lpk.dll
- %Program Files%\Windows NT\Accessories\lpk.dll
- %Program Files%\Windows NT\lpk.dll
- %Program Files%\Windows NT\Pinball\lpk.dll
- %Program Files%\WinPcap\lpk.dll
- %Windows%\$MSI31Uninstall_KB893803v2$\lpk.dll
- %Windows%\$MSI31Uninstall_KB893803v2$\spuninst\lpk.dll
- %Windows%\$NtUninstallWIC$\spuninst\lpk.dll
- %Windows%\assembly\NativeImages_v2.0.50727_32\ComSvcConfig\bb3c2f59a821abc54f420f3a9e051d6a\lpk.dll
- %Windows%\assembly\NativeImages_v2.0.50727_32\dfsvc\837fe02bdcf637d5bf1e5ffb935ebb80\lpk.dll
- %Windows%\assembly\NativeImages_v2.0.50727_32\MSBuild\aa99ebdd26e5d493fec18b1714458782\lpk.dll
- %Windows%\assembly\NativeImages_v2.0.50727_32\PresentationFontCac#\4ce7fd62d4107fbe996ab305eb21ee6a\lpk.dll
- %Windows%\assembly\NativeImages_v2.0.50727_32\ServiceModelReg\feac66e81309d67b48f7a9f4cb98f7c8\lpk.dll
- %Windows%\assembly\NativeImages_v2.0.50727_32\SMSvcHost\a098c66aa40d958878f3f5344e6ae1a4\lpk.dll
- %Windows%\assembly\NativeImages_v2.0.50727_32\WsatConfig\13f498f606b7cb97c086eea149b8c872\lpk.dll
- %Windows%\assembly\NativeImages_v4.0.30319_32\ComSvcConfig\51819c709096229ee187a7feee395d9f\lpk.dll
- %Windows%\assembly\NativeImages_v4.0.30319_32\dfsvc\b9b6069e6da06eb57e89cc544397f735\lpk.dll
- %Windows%\assembly\NativeImages_v4.0.30319_32\Microsoft.Workflow.#\6a8da5dd61b1fcfed27f84047a3e2bad\lpk.dll
- %Windows%\assembly\NativeImages_v4.0.30319_32\MSBuild\aa25092606e5e9826db7a7bd0adb9b2b\lpk.dll
- %Windows%\assembly\NativeImages_v4.0.30319_32\SMSvcHost\38f0d77629891e7808424103aaef0728\lpk.dll
- %Windows%\assembly\NativeImages_v4.0.30319_32\WsatConfig\3c0d21e75c9a48aba6fba3ddff0fcf39\lpk.dll
- %Windows%\lpk.dll
Step 7
Search and delete these folders
- %System Root%\DOCUME~1
- %System Root%\DOCUME~1\Wilbert
- %User Profile%\LOCALS~1
Step 8
Restart in normal mode and scan your computer with your Trend Micro product for files detected as BKDR_ZEGOST.YNPR. 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 9
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%\DogKiller.sys
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