Virus

W32/Opaserv.E

Analysis

  • Virus is 32bit, with a size of 24064 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 Brasil.pif and modifies the registry to load at Windows startup -
  • HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\
    CurrentVersion\Run
    Brasil = Windows\Brasil.pif

  • 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 Brasil.pif

  • The virus will modify the WIN.INI configuration file to load the dropped virus at Windows startup