How to recover a lost f5 c secret

If your familiar with a BIGIP F5, once you apply the   secret for  RADIUS or TACACS it is hash.

The quick and sure way to recover these secrets is to build a radius health check and set the debug option and  monitor the output. This is great if you have ucs config file &  with a secret that's unknown or not recorded.

The output within the  debug message will display the  text of the secret. The steps are;

1: craft a radius-health monitor and include some type of secret and enable the  'debug'

2: from the tmsh  list the radius monitor and edit the ltm monitor radius <mon-name> and replace the earlier  secret with the  hashed secret you want to decrypt.


e.g

 edit ltm monitor radius TEST

3:  From  F5 the unix bash shell find the debugged output after you have apply the  health monitor a defined pool, cat the  output and that would be your recovered secret. This works for recovering both RADIUS or TACACS secrets.

NOTE: this does not work for  users or admin  accounts, they are hashed using a one crypt function.


Ken Felix

NSE ( network security expert) and Route/Switching Engineer
kfelix  -----a----t---- socpuppets ---dot---com

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