W32/Opaserv.D

Analysis

• Virus is 32bit, with a size of 27,136 bytes and is a minor variant to W32/Opaserv.A
  
• Virus icon is that of a standard 32bit executable
  
• Virus attempts to connect to opasoft.com and update itself however the hard-coded URL is no longer available
  
• Virus copies itself to the Windows folder as ScrSvr.exe and modifies the registry to load at Windows startup -

  HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\
  CurrentVersion\Run
  ScrSvr = Windows\ScrSvr.exe

• The virus will attempt to use SMB through NetBIOS seeking machines on the same IP subnet
  
• The virus will scan IP addresses within the same domain for other shares, using NetBIOS via TCP port 137, seeking systems with open shares
  
• If a system is found with an open share, the virus will copy itself to that machine in the Windows folder as ScrSvr.exe
  
• The virus will modify the WIN.INI configuration file to load the dropped virus at Windows startup