No Service Password-Recovery

The No Service Password-Recovery feature is a security enhancement that prevents anyone with console access from accessing the router configuration and clearing the password. It also prevents anyone from changing the configuration register values and accessing NVRAM.

Finding Feature Information

Your software release may not support all the features documented in this module. For the latest caveats and feature information, see Bug Search Tool and the release notes for your platform and software release. To find information about the features documented in this module, and to see a list of the releases in which each feature is supported, see the feature information table.

Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to www.cisco.com/go/cfn. An account on Cisco.com is not required.

Prerequisites for No Service Password-Recovery

You must download and install ROM monitor (ROMMON) version 12.2(11)YV1 before you can use this feature.

Information About No Service Password-Recovery

Cisco Password Recovery Procedure

The Cisco IOS software provides a password recovery procedure that relies upon gaining access to ROMMON mode using the Break key during system startup. When the router software is loaded from ROMMON mode, the configuration is updated with the new password.

The password recovery procedure enables anyone with console access, the ability to access the router and its network. The No Service Password-Recovery feature prevents the completion of the Break key sequence and the entering of ROMMON mode during system startups and reloads.

Configuration Registers and System Boot Configuration

The lowest four bits of the configuration register (bits 3, 2, 1, and 0) form the boot field. The boot field determines if the router boots manually from ROM or automatically from flash or the network. For example, when the configuration register boot field value is set to any value from 0x2 to 0xF, the router uses the boot field value to form a default boot filename for autobooting from a network server.


Note

By default, the no confirm prompt and message are not displayed after reloads.

How to Enable No Service Password-Recovery

Upgrading the ROMMON Version

If your router or access server does not find a valid system image to load, the system will enter ROMMON mode. ROMMON mode can also be accessed by interrupting the boot sequence during startup.

Another method for entering ROMMON mode is to set the configuration register so that the router automatically enters ROMMON mode when it boots. For information about setting the configuration register value, refer to the Cisco IOS Configuration Fundamentals Configuration Guide and Cisco IOS Network Management Configuration Guide .

Perform this task to upgrade your version of ROMMON.

SUMMARY STEPS

  1. reload
  2. set tftp-file ip-address ip-subnet-mask default-gateway tftp-server
  3. sync
  4. tftpdnld -u
  5. boot

DETAILED STEPS

  Command or Action Purpose
Step 1

reload

Example:


Router> reload

Reloads a Cisco IOS image. After you issue this command and respond to the system prompts as necessary, the system will begin reloading the system software image.

  • While the system is reloading, press the Break key or a Break key-combination just after the “Compiled <date> by” message appears. Pressing the Break key interrupts the boot sequence and puts the router into ROMMON mode.

Note 

The default Break key combination is Ctrl-C, but this may be configured differently on your system.

Step 2

set tftp-file ip-address ip-subnet-mask default-gateway tftp-server

Example:


ROMMON> set tftpabc 10.10.0.0 255.0.0.0 10.1.1.0 10.29.32.0

Displays all the created variables. The arguments are as follows:

  • tftp-file --Location of the new ROMMON image on the TFTP server. The length of the filename is a maximum of 45 characters.

  • ip-address --IP address on the router to connect to the TFTP server.

  • ip-subnet-mask --IP subnet mask of the router.

  • default-gateway --IP address of the gateway of the TFTP server.

  • tftp-server --IP address of the TFTP server from which the image will be downloaded.

Note 

This command is not supported on the Cisco ASR 1000 and Cisco 800 series routers.

Step 3

sync

Example:


ROMMON> sync

Saves the changes to the image.

Step 4

tftpdnld -u

Example:


ROMMON> tftpdnld -u

Downloads the new ROMMON image from the TFTP server.

  • Reset if prompted.

Step 5

boot

Example:


ROMMON> boot

Boots the router with the Cisco IOS image in flash memory.

Verifying the Upgraded ROMMON Version

To verify that you have an upgraded version of ROMMON, use the show version command: 


Router# show version
Cisco IOS Software, C828 Software (C828-K9OS&6-M), Version 12.3 (20040702:094716)
[userid 168]
Copyright (c) 1986-2004 by Cisco Systems, Inc.
ROM: System Bootstrap, Version 12.2(11)YV1, Release Software (fc1)
Router uptime is 22 minutes
System returned to ROM by reload
.
.
.

Enabling No Service Password-Recovery


Note

As a precaution, a valid Cisco IOS image should reside in the bootflash before this feature is enabled.

If you plan to enter the no service password-recovery command, Cisco recommends that you save a copy of the system configuration file in a location away from the device.

Before you begin

Perform this task to enable the No Service Password-Recovery feature:

SUMMARY STEPS

  1. enable
  2. show version
  3. configure terminal
  4. config-register value
  5. no service password-recovery
  6. exit

DETAILED STEPS

  Command or Action Purpose
Step 1

enable

Example:


Router> enable

Enables privileged EXEC mode.

  • Enter your password if prompted.

Step 2

show version

Example:


Router# show version

Displays information about the system software, including configuration register settings.

  • The configuration register must be set to autoboot before entering the no service password-recovery command.

Step 3

configure terminal

Example:


Router# configure terminal

Enters global configuration mode.

Step 4

config-register value

Example:


Router(config)# config-register 0x2102

(Optional) Changes the configuration register setting.

  • If necessary, change the configuration register setting so the router is set to autoboot.

Step 5

no service password-recovery

Example:


Router(config)# no service password-recovery

Disables password-recovery capability at the system console.

Step 6

exit

Example:


Router(config)# exit

Exits global configuration mode and returns to EXEC mode.

Recovering a Device from the No Service Password-Recovery Feature

To recover a device once the No Service Password-Recovery feature has been enabled, use the telnet client only (SSH is not supported). This telnet client is capable of breaking out of the current session by pressing “Ctrl+]” keys together to arrive at the “telnet>” prompt. At this prompt, you can send multiple strings of “send break” during the “#####” boot up window followed by the “Self decompressing the image :” message. You must send five to seven strings of “send break” during the break out session to arrive at the “Do you want to reset the router to factory default configuration and proceed [y/n] ?” prompt. Answer “yes” for the device to boot with the factory default configuration. If Putty client is used for the telnet session, use the break command from the drop down menu. For SecureCRT client with telnet session, press the “Ctrl +break” keys on the full keyboard. The router will not go into ROMmon mode during this recovering process.

If you do not confirm the Break key action, the router boots normally with the No Service Password-Recovery feature enabled.

Examples

This section provides the following examples of the process:

Confirmed Break

PASSWORD RECOVERY FUNCTIONALITY IS DISABLED
program load complete, entry point: 0x80013000, size: 0x8396a8
Self decompressing the image : ######################################################################
###################################################################### [OK]
telnet> send break
telnet> send break
telnet> send break
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-IPBASE-M), Version 12.3(26), RELEASE SOFTWARE (fc2)  
Technical Support: http://www.cisco.com/techsupport  
Copyright (c) 1986-2008 by cisco Systems, Inc.  
Compiled Mon 17-Mar-08 15:24 by dchih  
PASSWORD RECOVERY IS DISABLED.  
Do you want to reset the router to factory default configuration and proceed [y/n] ?  
Reset router configuration to factory default.
This product contains cryptographic features and is subject to United States and local country laws governing import, export, transfer and use. Delivery of Cisco cryptographic products does not imply third-party authority to import, export, distribute or use encryption.
Importers, exporters, distributors and users are responsible for compliance with U.S. and local country laws. By using this product you agree to comply with applicable laws and regulations. If you are unable to comply with U.S. and local laws, return this product immediately.
A summary of U.S. laws governing Cisco cryptographic products may be found at:
http://www.cisco.com/wwl/export/crypto/tool/stqrg.html
If you require further assistance please contact us by sending email to export@cisco.com.
Cisco C831 (MPC857DSL) processor (revision 0x00) with 46695K/2457K bytes of memory.
Processor board ID 0000 (1314672220), with hardware revision 0000 CPU rev number 7
3 Ethernet interfaces
4 FastEthernet interfaces
128K bytes of NVRAM.
24576K bytes of processor board System flash (Read/Write)
2048K bytes of processor board Web flash (Read/Write)
         --- System Configuration Dialog ---
Would you like to enter the initial configuration dialog? [yes/no]: no
!Start up configuration is erased.
SETUP: new interface FastEthernet1 placed in “up” state
SETUP: new interface FastEthernet2 placed in “up” state
SETUP: new interface FastEthernet3 placed in “up” state
SETUP: new interface FastEthernet4 placed in “up” state
Press RETURN to get started!
Router>
Router> enable
Router# show startup configuration
startup-config is not present
Router# show running-config | in
cl service
no service pad
service timestamps debug datetime msec
service timestamps log datetime msec
no service password-encryption
!The “no service password-recovery” is disabled.
Unconfirmed Break

PASSWORD RECOVERY FUNCTIONALITY IS DISABLED
telnet> send break
program load complete, entry point: 0x80013000, size: 0x8396a8
Self decompressing the image : ##################################################################################### [OK]
telnet> send break
telnet> send break
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-IPBASE-M), Version 12.3(26), RELEASE SOFTWARE (fc2)  
Technical Support: http://www.cisco.com/techsupport  
Copyright (c) 1986-2008 by cisco Systems, Inc.  
Compiled Mon 17-Mar-08 15:24 by dchih  
PASSWORD RECOVERY IS DISABLED.  
Do you want to reset the router to factory default configuration and proceed [y/n] ?  
PASSWORD RECOVERY IS DISABLED.
Do you want to reset the router to factory default configuration and proceed [y/n] ? 
!The user enters “N” here.
This product contains cryptographic features and is subject to United States and local country laws governing import, export, transfer and use. Delivery of Cisco cryptographic products does not imply third-party authority to import, export, distribute or use encryption.
Importers, exporters, distributors and users are responsible for compliance with U.S. and local country laws. By using this product you agree to comply with applicable laws and regulations. If you are unable to comply with U.S. and local laws, return this product immediately.
A summary of U.S. laws governing Cisco cryptographic products may be found at: http://www.cisco.com/wwl/export/crypto/tool/stqrg.html
If you require further assistance please contact us by sending email to export@cisco.com.
Cisco C831 (MPC857DSL) processor (revision 0x00) with 46695K/2457K bytes of memory.
Processor board ID 0000 (1314672220), with hardware revision 0000
CPU rev number 7
3 Ethernet interfaces
4 FastEthernet interfaces
128K bytes of NVRAM.
24576K bytes of processor board System flash (Read/Write)
2048K bytes of processor board Web flash (Read/Write)
Press RETURN to get started!
!The Cisco IOS software boots as if it is not interrupted.
Router> enable
Router#
Router# show startup config
Using 984 out of 131072 bytes
!
version 12.3
no service pad
service timestamps debug datetime msec
service timestamps log datetime msec
no service password-encryption
no service password-recovery
!
hostname Router
!
boot-start-marker
boot-end-marker
!
memory-size iomem 5
!
no aaa new-model
ip subnet-zero
!
ip ips po max-events 100
no ftp-server write-enable
!
interface Ethernet0
 no ip address
 shutdown
!
interface Ethernet1
 no ip address
 shutdown
 duplex auto
!
interface Ethernet2
 no ip address
 shutdown
!
interface FastEthernet1
 no ip address
 duplex auto
 speed auto
!
interface FastEthernet2
 no ip address
 duplex auto
 speed auto
!
interface FastEthernet3
 no ip address
 duplex auto
 speed auto
!
interface FastEthernet4
 no ip address
 duplex auto
 speed auto
!
ip classless
!
ip http server
no ip http secure-server
!
control-plane
!
line con 0
 no modem enable
 transport preferred all
 transport output all
line aux 0
line vty 0 4
!
scheduler max-task-time 5000
end
Router# show running-config | incl service
no service pad
service timestamps debug datetime msec
service timestamps log datetime msec
no service password-encryption
no service password-recovery
end

Configuration Examples for No Service Password-Recovery

Disabling Password Recovery Example

The following example shows how to obtain the configuration register setting (which is set to autoboot), disable password recovery capability, and then verify that the configuration persists through a system reload: 


Router# show version
Cisco Internetwork Operating System Software 
IOS (tm) 5300 Software (C7200-P-M), Version 12.3(8)YA, RELEASE SOFTWARE (fc1)
TAC Support: http://www.cisco.com/tac
Copyright (c) 1986-2004 by Cisco Systems, Inc.
Compiled Wed 05-Mar-04 10:16 by xxx
Image text-base: 0x60008954, data-base: 0x61964000
ROM: System Bootstrap, Version 12.3(8)YA , RELEASE SOFTWARE (fc1)
.
.
.
125440K bytes of ATA PCMCIA card at slot 0 (Sector size 512 bytes).
8192K bytes of Flash internal SIMM (Sector size 256K).
Configuration register is 0x2102
Router# configure terminal
Router(config)# no service password-recovery
WARNING:
Executing this command will disable the password recovery mechanism.
Do not execute this command without another plan for password recovery.
Are you sure you want to continue? [yes]: yes
.
.
.
Router(config)# exit
Router#
Router# reload
Proceed with reload? [confirm] yes
00:01:54: %SYS-5-RELOAD: Reload requested
System Bootstrap, Version 12.3...
Copyright (c) 1994-2004 by cisco Systems, Inc.
C7400 platform with 262144 Kbytes of main memory
PASSWORD RECOVERY FUNCTIONALITY IS DISABLED
.
.
.

Additional References

The following sections provide references related to the No Service Password-Recovery feature.

Related Documents

Related Topic

Document Title

Setting, changing, and recovering lost passwords

“ Configuring Security with Passwords, Privilege Levels, and Login Usernames for CLI Sessions on Networking Devices ” feature module

Loading system images and rebooting

“ Using the Cisco IOS Integrated File System ” feature module

Security commands: complete command syntax, command mode, command history, defaults, usage guidelines, and examples

Cisco IOS Security Command Reference

Cisco IOS commands

Cisco IOS Master Commands List, All Releases

Standards

Standards

Title

None

--

MIBs

MIBs

MIBs Link

None

To locate and download MIBs for selected platforms, Cisco IOS releases, and feature sets, use Cisco MIB Locator found at the following URL:

http://www.cisco.com/go/mibs

RFCs

RFCs

Title

No new or modified RFCs are supported by this feature.

--

Technical Assistance

Description

Link

The Cisco Support website provides extensive online resources, including documentation and tools for troubleshooting and resolving technical issues with Cisco products and technologies.

To receive security and technical information about your products, you can subscribe to various services, such as the Product Alert Tool (accessed from Field Notices), the Cisco Technical Services Newsletter, and Really Simple Syndication (RSS) Feeds.

Access to most tools on the Cisco Support website requires a Cisco.com user ID and password.

http://www.cisco.com/cisco/web/support/index.html

Feature Information for No Service Password-Recovery

The following table provides release information about the feature or features described in this module. This table lists only the software release that introduced support for a given feature in a given software release train. Unless noted otherwise, subsequent releases of that software release train also support that feature.

Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to www.cisco.com/go/cfn. An account on Cisco.com is not required.
Table 1. Feature Information for No Service Password-Recovery

Feature Name

Releases

Feature Information

No Service Password-Recovery

12.3(8)YA

12.3(14)T

15.1(1)SY

Cisco IOS XE Release 3.10

The No Service Password-Recovery feature is a security enhancement that prevents anyone with console access from accessing the router configuration and clearing the password. It also prevents anyone from changing the configuration register values and accessing NVRAM.

This feature was introduced in Cisco IOS Release 12.3(8)YA.

This feature was integrated into Cisco IOS Release 12.3(14)T.

This feature was integrated into Cisco IOS Release 15.1(1)SY.

The following command was introduced: service password-recovery .

This feature was integrated into Cisco IOS XE Release 3.10 for Cisco ASR 1000 Series Aggregation Services Routers.

The following command was modified: service password-recovery . The strict keyword was added to the no form of this command.