Backdoor.Win32.FARFLI.SMAL01
Backdoor:Win32/Zegost.CQ!bit (Microsoft); Trojan-FRKV!DEC7D07E6418 (McAfee); Trojan.Win32.Siscos.zdc (Kaspersky); Trojan.Win32.Generic!BT (Sunbelt)
Windows
![](/vinfo/imgFiles/legend.jpg)
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.
It deletes itself after execution.
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%\setsvchost.exe
(Note: %Windows% is the Windows folder, where it usually is C:\Windows on all Windows operating system versions.)
It adds the following processes:
- %Windows%\setsvchost.exe
- %Windows%\Microsoft.NET\Framework\v4.0.30319\mscorsvw.exe
- %System%\svchost.exe -k LocalServiceAndNoImpersonation
- %Windows%\Microsoft.NET\Framework64\v4.0.30319\mscorsvw.exe
- %System%\sppsvc.exe
- "%System Root%\Program Files\Windows Media Player\wmpnetwk.exe"
- %System%\svchost.exe -k WerSvcGroup
- %System%\sc.exe start w32time task_started
- %System%\sdclt.exe /CONFIGNOTIFICATION
- taskhost.exe SYSTEM
- %System%\wsqmcons.exe
- taskhost.exe $(Arg0)
- %System%\svchost.exe -k LocalService
- %Windows%\setsvchost.exe Win7
- %System%\schtasks.exe /delete /f /TN "Microsoft\Windows\Customer Experience Improvement Program\Uploader"
(Note: %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.. %System Root% is the Windows root folder, where it usually is C:\ on all Windows operating system versions.)
It creates the following folders:
- %All Users Profile%\Microsoft\Windows\Sqm\Upload
- %All Users Profile%\Microsoft\Windows\Sqm\Manifest
- %All Users Profile%\Microsoft\Windows\Sqm\Sessions
- %Windows%\ServiceProfiles\NetworkService\AppData\Local\Microsoft
(Note: %All Users Profile% is the common user's profile folder, which is usually C:\Documents and Settings\All Users on Windows 2000(32-bit), XP, and Server 2003(32-bit), or C:\ProgramData on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit). . %Windows% is the Windows folder, where it usually is C:\Windows on all Windows operating system versions.)
Autostart Technique
This Backdoor registers itself as a system service to ensure its automatic execution at every system startup by adding the following registry entries:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\Cdefgh
ImagePath = "%Windows%\setsvchost.exe"
Other System Modifications
This Backdoor deletes the following files:
- %User Temp%\crt.dll
- %Windows%\LastGood.Tmp
(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(32-bit), XP, and Server 2003(32-bit), or C:\Users\{user name}\AppData\Local\Temp on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit).. %Windows% is the Windows folder, where it usually is C:\Windows on all Windows operating system versions.)
It adds the following registry keys:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\marktime
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\HomeGroup\
UIStatusCache
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer\
SessionInfo\1\WHCIconStartup
It adds the following registry entries:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
services\Cdefgh
Description = "Cdefghij Lmnopqrst Vwxyabc Efghijkl Nop"
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
services\Cdefgh
Group = "Default"
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
services\Cdefgh
InstallTime = "2019-06-19 10:00"
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
services\Cdefgh
MarkTime = "2019-06-19 10:00"
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
services\marktime
MarkTime = "2019-06-19 10:02"
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\HomeGroup\
UIStatusCache
UIStatus = "560"
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\HomeGroup\
UIStatusCache
OnlyMember = "0"
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\NetworkList\
Nla\Cache\Intranet
{89BCDCB3-5725-45A2-94AB-2D6B641209B0} = "\x00PV\xbcl%"
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Security Center
cval = "0"
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\Cdefgh
DisplayName = "Cdefgh Jklmnopq Stuvwxya Cdef"
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\Cdefgh
Start = "SERVICE_AUTO_START"
It modifies the following registry entries:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
services\W32Time
Type = "16"
(Note: The default value data of the said registry entry is 20.)
Dropping Routine
This Backdoor drops the following files:
- %All Users Profile%\Microsoft\Windows\DRM\drmstore.hds
- %All Users Profile%\Microsoft\Windows\DRM\v3ks.sec
- %System%\7293460.bak
- %AppDataLocal%\Microsoft\Media Player\CurrentDatabase_372.wmdb
(Note: %All Users Profile% is the common user's profile folder, which is usually C:\Documents and Settings\All Users on Windows 2000(32-bit), XP, and Server 2003(32-bit), or C:\ProgramData on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit). . %System% is the Windows system folder, where it usually is C:\Windows\System32 on all Windows operating system versions.. %AppDataLocal% is the Local Application Data folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Application Data on Windows 2000(32-bit), XP, and Server 2003(32-bit), or C:\Users\{user name}\AppData\Local on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit).)
Other Details
This Backdoor connects to the following possibly malicious URL:
- http://d.{BLOCKED}l.cn
- http://www.{BLOCKED}{BLOCKED}.com
- http://212951jh19.{BLOCKED}k.la
It deletes itself after execution.
This report is generated via an automated analysis system.
SOLUTION
Step 1
Before doing any scans, Windows 7, Windows 8, Windows 8.1, and Windows 10 users must disable System Restore to allow full scanning of their computers.
Step 2
Identify and terminate files detected as Backdoor.Win32.FARFLI.SMAL01
- Windows Task Manager may not display all running processes. In this case, please use a third-party process viewer, preferably Process Explorer, to terminate the malware/grayware/spyware file. You may download the said tool here.
- If the detected file is displayed in either Windows Task Manager or Process Explorer but you cannot delete it, restart your computer in safe mode. To do this, refer to this link for the complete steps.
- If the detected file is not displayed in either Windows Task Manager or Process Explorer, continue doing the next steps.
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
- marktime
- In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\HomeGroup
- UIStatusCache
- In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\SessionInfo\1
- WHCIconStartup
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\CurrentControlSet\services\Cdefgh
- Description = "Cdefghij Lmnopqrst Vwxyabc Efghijkl Nop"
- In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services\Cdefgh
- Group = "Default"
- In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services\Cdefgh
- InstallTime = "2019-06-19 10:00"
- In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services\Cdefgh
- MarkTime = "2019-06-19 10:00"
- In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services\marktime
- MarkTime = "2019-06-19 10:02"
- In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\HomeGroup\UIStatusCache
- UIStatus = "560"
- In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\HomeGroup\UIStatusCache
- OnlyMember = "0"
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\NetworkList\Nla\Cache\Intranet
- {89BCDCB3-5725-45A2-94AB-2D6B641209B0} = "\x00PV\xbcl%"
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Security Center
- cval = "0"
- In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Cdefgh
- DisplayName = "Cdefgh Jklmnopq Stuvwxya Cdef"
- In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Cdefgh
- Start = "SERVICE_AUTO_START"
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\SYSTEM\CurrentControlSet\services\W32Time
- From: Type = "16"
To: Type = ""20""
- From: Type = "16"
Step 6
Search and delete these components
- %All Users Profile%\Microsoft\Windows\DRM\drmstore.hds
- %All Users Profile%\Microsoft\Windows\DRM\v3ks.sec
- %System%\7293460.bak
- %AppDataLocal%\Microsoft\Media Player\CurrentDatabase_372.wmdb
Step 7
Search and delete these folders
- %All Users Profile%\Microsoft\Windows\Sqm\Upload
- %All Users Profile%\Microsoft\Windows\Sqm\Manifest
- %All Users Profile%\Microsoft\Windows\Sqm\Sessions
- %Windows%\ServiceProfiles\NetworkService\AppData\Local\Microsoft
Step 8
Scan your computer with your Trend Micro product to delete files detected as Backdoor.Win32.FARFLI.SMAL01. 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 the following Trend Micro Support pages 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%\crt.dll
- %Windows%\LastGood.Tmp
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