W32/Sdbot-NB is a worm which attempts to spread to remote network shares. It also contains backdoor Trojan functionality, allowing unauthorised remote access to the infected computer via IRC channels while running in the background as a service process.
W32/Sdbot-NB copies itself to the Windows system folder as SAGE.EXE and creates the following registry entry to run itself on system startup:
Laptop Access = Sage.exe
W32/Sdbot-NB spreads to network shares with weak passwords as a result of the backdoor Trojan element receiving the appropriate command from a remote user.
W32/Tzet-B is a network worm.
W32/Tzet-B searches the local network for computers with weak or no passwords on the administrator or admin accounts to which it can copy itself.