Trojan.PS1.SILENTKILL.THHOIBC
Ransom:BAT/GenRansom.A!hoa (MICROSOFT); Bat.DelShadow.43996 (QUICKHEAL)
Windows
![](/vinfo/imgFiles/legend.jpg)
Threat Type: Trojan
Destructiveness: No
Encrypted: No
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
10,656 bytes
PS1
No
09 Aug 2023
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 adds the following processes:
- cmd.exe /c assoc .README=txtfile
- wbadmin stop job
- wbadmin delete catalog -quiet
- wbadmin delete systemstatebackup
- wbadmin delete systemstatebackup - keepversions:0
- wbadmin delete backup
- wmic shadowcopy delete
- vssadmin delete shadows /all /quiet
- bcedit /set {default} bootstatuspolicy ignoreallfailures
- bcedit /set {default} recoveryenabled no
- wevtutil cl Security
- wevtutil cl Application
- wevtutil cl System
Other System Modifications
This Trojan modifies the following registry entries:
HKEY_LOCAL_MACHINE\SYSTEM\CurentControlSet\
Control\Terminal Server
fDenyTSConnections = 0
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows Defender\Real-Time Protection
SpyNetReporting = 0
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows Defender\Real-Time Protection
SubmitSamplesConsent = 0
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows Defender\Features
TamperProtection = 4
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows Defender
DisableAntiSpyware = 1
HKEY_LOCAL_MACHINE\SOFTWARE\Policies\
Microsoft\Windows Defender
DisableAntiSpyware = 1
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Policies\
System
legalnoticecaption = Welcome
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Policies\
System
legalnoticecaption = Welcome aboard
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Control\Terminal Server\WinStations\
RDP-TCP
PortNumber = 4000
HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\
TrendMicro\PC-cillinNTCorp\CurrentVersion\
Misc.
Allow Uninstall = 1
Process Termination
This Trojan terminates the following services if found on the affected system:
- Backup
- Exchange
- HvHost
- Malwarebytes
- Oracle
- Quest
- Sharepoint
- SQL
- Veeam
- vmcompute
- vmicguestinterface
- vmicheartbeat
- vmickvpexchange
- vmicrdv
- vmicshutdown
- vmictimesync
- vmicvmsession
- vmicvss
- vmms
It terminates processes or services that contain any of the following strings if found running in the affected system's memory:
- AV related processes:
- acronis
- Agent
- agent
- agntsvc.exe
- agntsvc.exeagntsvc.exe
- agntsvc.exeencsvc.exe
- agntsvc.exeisqlplussvc.exe
- anvir.exe
- anvir64.exe
- arcserve
- barracuda
- ccleaner.exe
- ccleaner64.exe
- Endpoint
- endpoint
- Kaspersky
- Malware
- microsoft
- monitor
- protect
- secure
- security
- segurda
- Veeam
- veeam
- adobe
- AlwaysOn
- anydesk
- apache
- apache.exe
- autodesk
- Backup
- backup.exe
- center
- chrome
- Core.Service
- database
- dbeng50.exe
- dbsnmp.exe
- def
- dev
- encsvc.exe
- engine
- exchange
- far.exe
- firefox
- firefoxconfig.exe
- Framework
- http
- infopath.exe
- isqlplussvc.exe
- java
- kingdee.exe
- logmein
- manage
- Mongo
- msaccess.exe
- msftesql.exe
- mspub.exe
- mydesktopqos.exe
- mydesktopservice.exe
- mysqld.exe
- mysqld-nt.exe
- mysqld-opt.exe
- ncsvc.exe
- ocautoupds.exe
- ocomm.exe
- OCS Inventory
- ocssd.exe
- office
- oracle.exe
- oracle.exe
- procexp.exe
- QBCF
- QBData
- QBDB
- QuickBooks
- regedit.exe
- sage
- server
- silverlight
- solarwinds
- sprout
- sqbcoreservice.exe
- sql
- SQL
- sql.exe
- sqlagent.exe
- sqlbrowser.exe
- sqlserver.exe
- sqlservr.exe
- sqlwriter.exe
- synctime.exe
- tbirdconfig.exe
- teamviewer
- tomcat.exe
- tomcat6.exe
- u8.exe
- ufida.exe
- visio.exe
- vnc
- web
- xfssvccon.exe
Other Details
This Trojan does the following:
- It adds the following local group accounts with Administrator privileges:
- Administrators
- Remote Desktop Users
- It enables the firewall rule that allows RDP connections.
- It sends the MAC address of the victim via UDP to the broadcast IP.
- It modifies the Administrator user passsword.
- It modifies the Windows Defender settings to disable malware scanning and detection.
- It disables the following AV-related services:
- WdNisSvc
- WinDefend
- Sense
- WdnisDrv
- wdfilter
- wdboot
- It deletes the ComputerRestorePoint to prevent system recovery.
- It attempts to uninstall the following AV programs:
- Bitdefender
- TrendMicro
- Kaspersky
- It enables PowerShell remoting.
- It enables WinRm execution.
- It checks if a specific IP in its network has a running WinDefend service.
- It modifies the machine's lock screen title into the following strings:
- Welcome
- Welcome aboard
- It deletes all files in %User Temp%.
- It modifies the listening RDP port to 4000 and sets a Firewall rule to allow inbound connections.
- It modifies the Windows Defender settings to disable scanning of files and processes in all drives.
(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).)
SOLUTION
9.800
18.624.02
09 Aug 2023
18.625.00
10 Aug 2023
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 Trojan.PS1.SILENTKILL.THHOIBC
- 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
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.
- HKEY_LOCAL_MACHINE\SYSTEM\CurentControlSet\Control\Terminal Server
- fDenyTSConnections = 0
- fDenyTSConnections = 1
- HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows Defender\Real-Time Protection
- SpyNetReporting = 0
- SpyNetReporting = {Default Value}
- HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows Defender\Real-Time Protection
- SubmitSamplesConsent = 0
- SubmitSamplesConsent = {Default Value}
- HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows Defender\Features
- TamperProtection = 4
- TamperProtection = {Default Value}
- HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows Defender
- DisableAntiSpyware = 1
- DisableAntiSpyware = 0
- HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Windows Defender
- DisableAntiSpyware = 1
- DisableAntiSpyware = 0
- HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Policies\System
- legalnoticecaption = Welcome
- legalnoticecaption = {Default value}
- HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Policies\System
- legalnoticecaption = Welcome aboard
- legalnoticecaption = {Default value}
- HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Terminal Server\WinStations\RDP-TCP
- PortNumber = 4000
- PortNumber = {Default value}
- HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\TrendMicro\PC-cillinNTCorp\CurrentVersion\Misc.
- Allow Uninstall = 1
- Allow Uninstall = 0
Step 4
Scan your computer with your Trend Micro product to delete files detected as Trojan.PS1.SILENTKILL.THHOIBC. 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:
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