Password Recovery Procedure for the Cisco 2600 and 2800 Series Routers - Cisco
https://www.cisco.com/c/en/us/support/docs/routers/2600-series-multiservice-platforms/22188-pswdrec-2600.htmlIFM - Cisco IOS Enable Secret Type 5 Password Cracker
http://www.ifm.net.nz/cookbooks/cisco-ios-enable-secret-password-cracker.html