This KB will help with the SRX root password recovery process

Clients might have issues with their Radius server and have password as their second option. This might result in not being able to log into their SRX.

1) Reboot the box and press SPACE when you see the following screen to get to the loader prompt.

writing to flash...
Protected 1 sectors
Loading /boot/defaults/loader.conf
/kernel data=0x9f5c18+0xd8d68 syms=[0x4+0x7e350+0x4+0xb49c7]

Hit [Enter] to boot immediately, or space bar for command prompt.
Booting [/kernel] in 1 second...

Type '?' for a list of commands, 'help' for more detailed help.
loader>

2) Type “boot -s” in this prompt

loader>boot -s

3) After a while you will see a screen like below. Type “recovery” to continue

System watchdog timer disabled
Enter full pathname of shell or 'recovery' for root password recovery or RETURN

After that, you will get access to the SRX CLI and configure modes:

Starting CLI ...
root> configure 
Entering configuration mode

root# set system root-authentication plain-text-password 
New password:
Retype new password:

Note:

If you don’t see the prompt for recovery but instead “Enter root password”, then password recovery must have been disabled via the configuration “set system ports console insecure” which means you can’t recover the password via this method.