1) if you've just forgotten the netrangr user password, you can login as root, su to netrangr, then change the password (passwd).

2) If you've lost the root password, then you'll need to use unix utilities to recover the password

Password Recovery

http://www.cisco.com/warp/public/474/34.html

3) If you don't mind losing your config, then the simplest thing to do is pop your 3.0 recovery cd in the cd player and power off and power on. It will reimage your sensor, including installing solaris 8, with the default root password of attack. You may not even lose your config if you are using CSPM or the Unix director. After you load the recovery cd, run sysconfig-sensor, then just push down the old config from CSPM or the Unix director.

HTH

Jeff