In Cisco IOS Release 12.3(8)T, support for roll-back of the AutoSecure configuration is introduced. Roll-back enables a router to revert back to its preautosecure configuration state if the AutoSecure configuration fails.
System Logging Messages capture any changes or tampering of the AutoSecure configuration that were applied on the running configuration.
Note Prior to Cisco IOS Release 12.3(8)T, roll-back of the AutoSecure configuration is unavailable; thus, you should always save the running configuration before configuring AutoSecure.
http://www.cisco.com/univercd/cc/td/doc/product/software/ios124/124cr/hsec_r/sec_c1h.htm#wp1159652