Technical Information
To ensure autorun and distribution
Modifies the following registry keys
- [<HKLM>\SOFTWARE\Wow6432Node\Microsoft\Windows NT\CurrentVersion\Winlogon] 'Shell' = 'Explorer.exe RVHOST.exe'
- [<HKCU>\Software\Microsoft\Windows\CurrentVersion\Run] 'Yahoo Messengger' = '<SYSTEM32>\RVHOST.exe'
Creates or modifies the following files
- %WINDIR%\tasks\at1.job
- <SYSTEM32>\tasks\at1
Creates the following files on removable media
- <Drive name for removable media>:\new folder.exe
Malicious functions
To complicate detection of its presence in the operating system,
blocks execution of the following system utilities:
- Windows Task Manager (Taskmgr)
- Registry Editor (RegEdit)
modifies the following system settings:
- [<HKCU>\Software\Microsoft\Windows\CurrentVersion\Policies\Explorer] 'NofolderOptions' = '00000001'
Executes the following
- '%WINDIR%\syswow64\at.exe' /delete /yes
- '%WINDIR%\syswow64\at.exe' 09:00 /interactive /EVERY:m,t,w,th,f,s,su <SYSTEM32>\RVHOST.exe
Modifies file system
Creates the following files
- %WINDIR%\syswow64\rvhost.exe
- %WINDIR%\rvhost.exe
- %LOCALAPPDATA%\microsoft\windows\<INETFILES>\low\desktop.ini
- %LOCALAPPDATA%\microsoft\windows\<INETFILES>\low\content.ie5\desktop.ini
- %LOCALAPPDATA%\microsoft\windows\history\low\desktop.ini
- %LOCALAPPDATA%\microsoft\windows\history\low\history.ie5\desktop.ini
- %LOCALAPPDATA%\microsoft\windows\<INETFILES>\low\content.ie5\index.dat
- %LOCALAPPDATA%\microsoft\windows\<INETFILES>\low\content.ie5\z4swx2cb\desktop.ini
- %LOCALAPPDATA%\microsoft\windows\<INETFILES>\low\content.ie5\34odw0aj\desktop.ini
- %LOCALAPPDATA%\microsoft\windows\<INETFILES>\low\content.ie5\ap4kxwj1\desktop.ini
- %LOCALAPPDATA%\microsoft\windows\<INETFILES>\low\content.ie5\s33c6t25\desktop.ini
- %APPDATA%\microsoft\windows\cookies\low\index.dat
- %LOCALAPPDATA%\microsoft\windows\history\low\history.ie5\index.dat
Sets the 'hidden' attribute to the following files
- %WINDIR%\syswow64\rvhost.exe
- %LOCALAPPDATA%\microsoft\windows\<INETFILES>\low\desktop.ini
- %LOCALAPPDATA%\microsoft\windows\<INETFILES>\low\content.ie5\desktop.ini
- %LOCALAPPDATA%\microsoft\windows\<INETFILES>\low\content.ie5\z4swx2cb\desktop.ini
- %LOCALAPPDATA%\microsoft\windows\<INETFILES>\low\content.ie5\34odw0aj\desktop.ini
- %LOCALAPPDATA%\microsoft\windows\<INETFILES>\low\content.ie5\ap4kxwj1\desktop.ini
- %LOCALAPPDATA%\microsoft\windows\<INETFILES>\low\content.ie5\s33c6t25\desktop.ini
- %LOCALAPPDATA%\microsoft\windows\history\low\history.ie5\desktop.ini
- %LOCALAPPDATA%\microsoft\windows\history\low\desktop.ini
Network activity
TCP
HTTP GET requests
- http://www.fr###ebs.com/nhattruongquang/setting.nql
- http://www.microsoft.com/pki/certs/MicRooCerAut_2010-06-23.crt
- http://www.fr###ebs.com/nhattruongquang/setting.xls
UDP
- DNS ASK nh######glan2.0catch.com
- DNS ASK fr###ebs.com
- DNS ASK microsoft.com
Miscellaneous
Creates and executes the following
- '%WINDIR%\syswow64\cmd.exe' /C AT /delete /yes' (with hidden window)
- '%WINDIR%\syswow64\cmd.exe' /C AT 09:00 /interactive /EVERY:m,t,w,th,f,s,su <SYSTEM32>\RVHOST.exe' (with hidden window)
Executes the following
- '%WINDIR%\syswow64\cmd.exe' /C AT /delete /yes
- '%WINDIR%\syswow64\cmd.exe' /C AT 09:00 /interactive /EVERY:m,t,w,th,f,s,su <SYSTEM32>\RVHOST.exe
- '%WINDIR%\syswow64\rundll32.exe' "%WINDIR%\syswow64\Wininet.dll",DispatchAPICall 1
