- Cisco Networking: Password recovery

 

Introduction

This document describes the procedure for recovering an enable password or enable secret passwords. These passwords are used to protect          access to privileged EXEC and configuration modes. The enable password password can be recovered but the enable secret password is encrypted  and can only be replaced with a new password using the procedure below.

Note: This password recovery procedure works for the following Cisco products:

Cisco 806 Cisco 827 Cisco uBR900 Cisco 1003 Cisco 1004 Cisco 1005 Cisco 1400 Cisco 1600 Cisco 1700 Cisco 2600 Cisco 3600 Cisco 4500 Cisco 4700

Cisco AS5x00 Cisco 6x00 Cisco 7000 (RSP7000) Cisco 7100 Cisco 7200 Cisco 7500 Cisco uBR7100 Cisco uBR7200 Cisco uBR10000 Cisco 12000 Cisco LS1010 Catalyst 2948G-L3 Catalyst 4840G

Catalyst 4908G-L3 Catalyst 5500 (RSM) Catalyst 8510-CSR Catalyst 8510-MSR Catalyst 8540-CSR Catalyst 8540-MSR Cisco MC3810 Cisco NI-2 Cisco VG200 Analog Gateway Route Processor Module

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Step-by-Step Procedure

1. Attach a terminal or PC with terminal emulation to the console port of the router. Use the following terminal settings:
   9600 baud rate
   No parity
   8 data bits
   1 stop bit
2. If you still have access to the router, type show version and record the setting of the configuration register; it is usually 0x2102 or 0x102.


3. If you don't have access to the router (because of a lost login or tacacs password), you can safely consider that your configuration register is set to 0x2102.


4. Using the power switch, turn off the router and then turn it back on. Important: To simulate step 4 on a Cisco 6400, pull out and then replace the Node Route Processor (NRP) or Node Switch Processor (NSP) card. Important: To simulate step 4 on a Cisco 6x00 using NI-2, pull out and     then replace the NI-2 card.

 

5. Press Break on the terminal keyboard within 60 seconds of the power-up to put the router into ROMMON. If the break sequence doesn't work, see Possible            Key Combinations for Break Sequence During Password Recovery for other key combinations.

 

6. Type confreg 0x2142 at the rommon 1> prompt to boot from Flash without loading the configuration.


7. Type reset at the rommon 2> prompt. The router reboots but ignores its saved configuration.                                        
8. Type enable at the Router> prompt. You'll be in enable mode and see the Router# prompt.
9. Important: Type configure memory or copy startup-config running-config to copy the nonvolatile RAM (NVRAM) into memory.
10. Type write terminal or show running-config. The show running-config and write terminal commands show the configuration of the router. In this configuration you see under all the interfaces the shutdown command, which means all interfaces are currently shutdown. Also, you can see the passwords (enable password, enable secret, vty, console passwords, and so on) either in encrypted or unencrypted format.The unencrypted passwords can be re-used, the encrypted ones will have to be changed with a new one.
11. Type configure terminal and make the changes. The prompt is now hostname(config)#.
12. Type enable secret <password> to change the enable secret password, for example.
13. Issue the no shutdown command on every interface that is used. If you issue a show ip interface brief command, every interface that you want to use should be "up up".  
14. Type config-register 0x2102, or the value you recorded in step            2.
15. Press Ctrl-z or end to leave the configuration mode.The prompt is now hostname#.
16. Type write memory or copy running-config startup-config to commit the changes.

Type no after each setup question or press Ctrl-C to skip the initial setup procedure. 

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Example of Password Recovery Procedure

The example below presents an actual password recovery procedure. We created this example using a Cisco 2600. Even if you are not using a Cisco 2600, this example will be almost exactly what you experience on your product.

Router>enable
Password:
Password:
Password:
% Bad secrets

#Router>show versionCisco Internetwork Operating System Software
IOS (tm) C2600 Software (C2600-IS-M), Version 12.0(7)T, RELEASE SOFTWARE (fc2)
Copyright (c) 1986-1999 by cisco Systems, Inc.
Compiled Tue 07-Dec-99 02:21 by phanguye
Image text-base: 0x80008088, data-base: 0x80C524F8

ROM: System Bootstrap, Version 11.3(2)XA4, RELEASE SOFTWARE (fc1)

Router uptime is 3 minutes
System returned to ROM by abort at PC 0x802D0B60
System image file is "flash:c2600-is-mz.120-7.T"

cisco 2611 (MPC860) processor (revision 0x202) with 26624K/6144K bytes of memory.
Processor board ID JAB031202NK (3878188963)
M860 processor: part number 0, mask 49
Bridging software.
X.25 software, Version 3.0.0.
Basic Rate ISDN software, Version 1.1.
2 Ethernet/IEEE 802.3 interface(s)
2 Serial(sync/async) network interface(s)
1 ISDN Basic Rate interface(s)
32K bytes of non-volatile configuration memory.
8192K bytes of processor board System flash partition 1 (Read/Write)
8192K bytes of processor board System flash partition 2 (Read/Write)
Configuration register is 0x2102Router>

!--- The router was just powercycled and during bootup a
!--- break sequence was sent to the router.!

*** System received an abort due to Break Key ***

signal= 0x3, code= 0x500, context= 0x813ac158
PC = 0x802d0b60, Vector = 0x500, SP = 0x80006030
rommon 1 > confreg 0x2142

You must reset or power cycle for new config to take effect

rommon 2 > reset

System Bootstrap, Version 11.3(2)XA4, RELEASE SOFTWARE (fc1)
Copyright (c) 1999 by cisco Systems, Inc.
TAC:Home:SW:IOS:Specials for info
C2600 platform with 32768 Kbytes of main memory

program load complete, entry point: 0x80008000, size: 0x6fdb4c

Self decompressing the image : ###############################
##############################################################
##############################################################
##############################################################
############################### [OK]

Restricted Rights Legend

Use, duplication, or disclosure by the Government is
subject to restrictions as set forth in subparagraph
(c) of the Commercial Computer Software - Restricted
Rights clause at FAR sec. 52.227-19 and subparagraph
(c) (1) (ii) of the Rights in Technical Data and Computer
Software clause at DFARS sec. 252.227-7013.

cisco Systems, Inc.
170 West Tasman Drive
San Jose, California 95134-1706

Cisco Internetwork Operating System Software
IOS (tm) C2600 Software (C2600-IS-M), Version 12.0(7)T, RELEASE SOFTWARE (fc2)
Copyright (c) 1986-1999 by cisco Systems, Inc.
Compiled Tue 07-Dec-99 02:21 by phanguye
Image text-base: 0x80008088, data-base: 0x80C524F8

cisco 2611 (MPC860) processor (revision 0x202) with 26624K/6144K bytes of memory.
Processor board ID JAB031202NK (3878188963)
M860 processor: part number 0, mask 49
Bridging software.
X.25 software, Version 3.0.0.
Basic Rate ISDN software, Version 1.1.
2 Ethernet/IEEE 802.3 interface(s)
2 Serial(sync/async) network interface(s)
1 ISDN Basic Rate interface(s)
32K bytes of non-volatile configuration memory.
8192K bytes of processor board System flash partition 1 (Read/Write)
8192K bytes of processor board System flash partition 2 (Read/Write)

--- System Configuration Dialog ---

Would you like to enter the initial configuration dialog? [yes/no]: n

Press RETURN to get started!

Router>

Router>enableRouter#copy startup-config running-config
Destination filename [running-config]?
1324 bytes copied in 2.35 secs (662 bytes/sec)
Router#
00:01:24: %LINEPROTO-5-UPDOWN: Line protocol on Interface BRI0/0:1, changed state to down
00:01:24: %LINEPROTO-5-UPDOWN: Line protocol on Interface BRI0/0:2, changed state to down
Router#configure terminalEnter configuration commands, one per line. End with CNTL/Z.
Router(config)#enable secret cisco
Router(config)#^Z
00:01:54: %SYS-5-CONFIG_I: Configured from console by console

Router#show ip interface brief
Interface      IP-Address        OK?     Method     Status                   Protocol
Ethernet0/0    10.200.40.37      YES     TFTP       administratively down    down
Serial0/0      unassigned        YES     TFTP       administratively down    down
BRI0/0         193.251.121.157   YES     unset      administratively down    down
BRI0/0:1       unassigned        YES     unset      administratively down    down
BRI0/0:2       unassigned        YES     unset      administratively down    down
Ethernet0/1    unassigned        YES     TFTP       administratively down    down
Serial0/1      unassigned        YES     TFTP       administratively down    down
Loopback0      193.251.121.157   YES     TFTP       up                       up
Router#configure terminal
Enter configuration commands, one per line. End with CNTL/Z.
Router(config)#interface Ethernet0/0
Router(config-if)#no shutdown
Router(config-if)#
00:02:14: %LINK-3-UPDOWN: Interface Ethernet0/0, changed state to up
00:02:15: %LINEPROTO-5-UPDOWN: Line protocol on Interface Ethernet0/0, changed state to up
Router(config-if)#interface BRI0/0
Router(config-if)#no shutdown
Router(config-if)#
00:02:26: %LINK-3-UPDOWN: Interface BRI0/0:1, changed state to down
00:02:26: %LINK-3-UPDOWN: Interface BRI0/0:2, changed state to down
00:02:26: %LINK-3-UPDOWN: Interface BRI0/0, changed state to up
00:02:115964116991: %ISDN-6-LAYER2UP: Layer 2 for Interface BR0/0, TEI 68 changed to up
Router(config-if)#^Z
Router#
00:02:35: %SYS-5-CONFIG_I: Configured from console by console

Router#copy running-config startup-config
Destination filename [startup-config]?
Building configuration...
[OK]

Router#show version
Cisco Internetwork Operating System Software
IOS (tm) C2600 Software (C2600-IS-M), Version 12.0(7)T, RELEASE SOFTWARE (fc2)
--- output truncated ---
2 Ethernet/IEEE 802.3 interface(s)
2 Serial(sync/async) network interface(s)
1 ISDN Basic Rate interface(s)
32K bytes of non-volatile configuration memory.
8192K bytes of processor board System flash partition 1 (Read/Write)
8192K bytes of processor board System flash partition 2 (Read/Write)
Configuration register is 0x2142Router#configure terminal
Enter configuration commands, one per line. End with CNTL/Z.
Router(config)#config-register 0x2102
Router(config)#^Z
00:03:20: %SYS-5-CONFIG_I: Configured from console by console

Router#show version
Cisco Internetwork Operating System Software
IOS (tm) C2600 Software (C2600-IS-M), Version 12.0(7)T, RELEASE SOFTWARE (fc2)
--- output truncated ---
2 Ethernet/IEEE 802.3 interface(s)
2 Serial(sync/async) network interface(s)
1 ISDN Basic Rate interface(s)
32K bytes of non-volatile configuration memory.
8192K bytes of processor board System flash partition 1 (Read/Write)
8192K bytes of processor board System flash partition 2 (Read/Write)

Configuration register is 0x2142 (will be 0x2102 at next reload)
Router#