How to break password of Cisco 3750 switch without rebooting.

[Nikhilkhandekar]

I have a Cisco 3750 switch in my network. Previous administrative did not share the configuration backup neither credentials to login into the device. Also I am not sure whether configuration was saved in the startup config. Is there any way where I could break the password and take the configuration backup without rebooting the switch ?

[Moses Fernandes]

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@Nikhilkhandekar wrote:
Is there any way where I could break the password and take the configuration backup without rebooting the switch ?

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Tell the HR to call him and inform him that his F&F (full and final settlement) wont be done unless he share the password.

Its a simple trick and work most of the time. Only catch here is that they should call him before his F&F is done.

One of the other options to recover password is provided here:

https://www.cisco.com/c/en/us/td/docs/switches/lan/catalyst3750/software/release/12-2_25_sec/configuration/guide/3750scg/swtrbl.html#wp1021182

https://www.cisco.com/c/en/us/td/docs/switches/lan/catalyst3750/software/release/12-2_55_se/configuration/guide/scg3750/swtrbl.html#25330

Also try your luck by accessing switch via the consol port. TRY!!!

Hope thats helpful.

Regards,

Moses.

[pieterh]

NO.

all password recovery procedures require you to
- reboot the switch.
- interrupt the boot process
- boot without loading the configuration (hence without the password)

the best option left is if you have physical access tot the console port and try if there is no login enabled on the console. but i guess you already tried that without luck.

other strategy could be using a second stack member
this does not break the password, but you can retrieve the configuration

also you can replace the switch with a switch with a known password.

- prepare a switch with NO configuration, preferrably the same ios version as the existing switch.

- add this switch to the stack as member 2
- remove stack member 2
  now you have a switch with a copy of the configuration of the complete stack including the configuration of member 1
- do password recovery on member 2 and view/save  the configuration
- if desired modify member 2 to replace member 1 (renumber switch etc)

[Leo Laohoo]

A dictionary or brute force could but this will take time. 

I'd rather say that the switch "crashed" and perform the password recovery.