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ASA 5555-X Password Recovery

johnlloyd_13
Level 9
Level 9

hi,

i got locked out on a new ASA 5555-X running in multiple mode when i applied AAA on the admin context. i tried to reboot the primary/active but got stuck troubleshooting the secondary standby.

so i did a password recovery. but after issuing boot, the config on on the ASA system context were gone. i issued a copy start run but it didn't retrieve the old config (still ciscoasa#).

i was able to retrieve admin context configuration when i reconfigured the admin url-config.

can someone advise what is the correct procedure for the password recovery on a 5555-X?

 

rommon #0> confreg

Current Configuration Register: 0x00000001
Configuration Summary:
  boot default image from Flash

Do you wish to change this configuration? y/n [n]: y
enable boot to ROMMON prompt? y/n [n]:
enable TFTP netboot? y/n [n]:
enable Flash boot? y/n [n]:
select specific Flash image index? y/n [n]:
disable system configuration? y/n [n]: y
go to ROMMON prompt if netboot fails? y/n [n]:
enable passing NVRAM file specs in auto-boot mode? y/n [n]:
disable display of BREAK or ESC key prompt during auto-boot? y/n [n]:

Current Configuration Register: 0x00000040
Configuration Summary:
  boot ROMMON
  ignore system configuration

Update Config Register (0x40) in NVRAM...

rommon #1> boot
Launching BootLoader...
Boot configuration file contains 1 entry.

 

!! 5555-X went to ciscoasa>     !! CHANGE BACK config-register to 0x00000001 AND ISSUED write memory

3 Replies 3

netcoms
Level 1
Level 1

Just for reference if someone else is looking for an answer, the procedure you followed seems to be correct.

This guide provides more details on how to recover the password on the ASA: https://www.cisco.com/c/en/us/td/docs/security/asa/asa93/configuration/general/asa-general-cli/basic-hostname-pw.html#91949

 

 

moses_og
Level 1
Level 1

You skipped a few steps at the end. You shouldn't copy old confreg value back to the default until you have done

 

1. copy startup-config

2. Made your password changes

 

Now you can put your confreg values back

and then reload your switch

 

To recover passwords for the ASA, perform the following steps:

 

Step 1 Connect to the ASA console port according to the instructions in "Accessing the Command-Line Interface" section."

 

Step 2 Power off the ASA, and then power it on.

 

Step 3 After startup, press the Escape key when you are prompted to enter ROMMON mode.

 

Step 4 To update the configuration register value, enter the following command:

 

rommon #1> confreg 0x41

 

Update Config Register (0x41) in NVRAM...
 

 

Step 5 To set the ASA to ignore the startup configuration, enter the following command:

 

rommon #1> confreg
 

 

The ASA displays the current configuration register value, and asks whether you want to change it:

 

Current Configuration Register: 0x00000041
Configuration Summary: 
  boot default image from Flash
  ignore system configuration
 
Do you wish to change this configuration? y/n [n]: y
 

 

Step 6 Record the current configuration register value, so you can restore it later.

 

Step 7 At the prompt, enter Y to change the value.

 

The ASA prompts you for new values.

 

Step 8 Accept the default values for all settings. At the prompt, enter Y.

 

Step 9 Reload the ASA by entering the following command:

 

rommon #2> boot
Launching BootLoader...
Boot configuration file contains 1 entry.
Loading disk0:/asa800-226-k8.bin... Booting...Loading...

 

 

 

The ASA loads the default configuration instead of the startup configuration.

 

Step 10 Access the privileged EXEC mode by entering the following command:

 

hostname> enable
 

 

Step 11 When prompted for the password, press Enter.

 

The password is blank.

 

Step 12 Load the startup configuration by entering the following command:

 

hostname# copy startup-config running-config
 

 

Step 13 Access the global configuration mode by entering the following command:

 

hostname# configure terminal
 

 

Step 14 Change the passwords, as required, in the default configuration by entering the following commands:

 

hostname(config)# password password
hostname(config)# enable password password
hostname(config)# username name password password
 

 

Step 15 Load the default configuration by entering the following command:

 

hostname(config)# no config-register 
 

 

The default configuration register value is 0x1.

 

Step 16 Save the new passwords to the startup configuration by entering the following command:

 

hostname(config)# copy running-config startup-config

 

 

Disabling Password Recovery

 

You might want to disable password recovery to  ensure that unauthorized users cannot use the password recovery  mechanism to compromise the ASA.

 

On the ASA, the no service password-recovery command prevents a user from entering ROMMON mode with the configuration intact. When a user enters ROMMON mode, the ASA  prompts the user to erase all Flash file systems. The user cannot enter  ROMMON mode without first performing this erasure. If a user chooses  not to erase the Flash file system, the ASA  reloads. Because password recovery depends on using ROMMON mode and  maintaining the existing configuration, this erasure prevents you from  recovering a password. However, disabling password recovery prevents  unauthorized users from viewing the configuration or inserting different  passwords. In this case, to restore the system to an operating state,  load a new image and a backup configuration file, if available.

 

source from https://community.cisco.com/t5/security-documents/asa-password-recovery/ta-p/3126046

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