Cisco ASA Firewall Password Removal

  • Estimated Time: 2 – 30min
  • Number Of Commands: 8-9
  • Difficulty: 4
  • Requirements:
    • Console Cable
    • Cisco ASA Firewall
    • Putty
  • Notes: Correct baud rate must be set to ensure proper connection. Doing the procedure below will remove the password without losing configuration data.


Step 1: Preparation and Putty installation

Connect console cable to Cisco ASA Firewall and use Windows or Linux to establish a console connection.


Install putty via your package manager


Step 2: Launching putty and inputting connection info


putty -serial -sercfg 19200 /dev/ttyUSB0


Fill in the baud rate, the COM number listed in device manager for your serial cable and the baud speed; click open.

Step 3: Boot up Cisco ASA, Change Confreg and Reboot

Insert the power cord to your Cisco asa firewall and press the esc or pause break to enter rommon mode. After entering rommon mode, enter the command below

Confreg 0x41
(forces Cisco to ignore startup configuration)
(Reboots Cisco asa while ignoring the default startup configuration)

Step 4: Remove password and load old configuration, reboot to rommon

The Cisco asa should now be booted to the default prompt reading “ciscoasa>” or something similar depending on the version of the firewall.

(Enters enabled mode, a password prompt should now appear. The password will be either blank, Cisco or cisco as the device is running on the confreg 0x41 register to bypass startup config)
copy startup-config running-config
(Will load the old startup configuration into the Cisco asa but should still remain in enabled mode)
configure terminal
(Enters global configuration mode)
enable password cisco
(Changed the old enabled password that was set on the original configuration to your desired password. Here I am using cisco as the desired password.)
copy running-config startup-config
(Saves the current start up configuration that you modified to the default config 0x1 register, now reboot to rommon again)

Step 5: Change to original confreg register and reboot

after booting back into rommon mode by using the pause and break keys enter the following commands to set the Cisco asa back to the default register

confreg 0x1
(Change to original startup config)
(Reboot the device back into the original startup configuration, the password will now be what you set it to in the previous steps. Congratulations you removed the password from your Cisco asa firewall without losing valuable configuration data. )


%d bloggers like this: