简单的说一下 cisco路由器的密码破解

　　破解密码原则 只删除密码不破坏配置

　　1 重启 路由器 按 ctrl + pause break 键 进入mini IOS

　　2 修改寄存器值改变启动次序

　　rommon 1 > confreg 0x2142

　　3 在mini IOS下重启路由

　　rommon 2 > reset

　　System Bootstrap, Version 12.1(3r)T2, RELEASE SOFTWARE (fc1)

　　Copyright (c) 2000 by cisco Systems, Inc.

　　cisco 2621 (MPC860) processor (revision 0x200) with 60416K/5120K bytes of memory

　　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-I-M), Version 12.2(28), RELEASE SOFTWARE (fc5)

　　Technical Support: http://www.cisco.com/techsupport

　　Copyright (c) 1986-2005 by cisco Systems, Inc.

　　Compiled Wed 27-Apr-04 19:01 by miwang

　　cisco 2621 (MPC860) processor (revision 0x200) with 60416K/5120K bytes of memory

　　.

　　Processor board ID JAD05190MTZ (4292891495)

　　M860 processor: part number 0, mask 49

　　Bridging software.

　　X.25 software, Version 3.0.0.

　　2 FastEthernet/IEEE 802.3 interface(s)

　　2 Low-speed serial(sync/async) network interface(s)

　　32K bytes of non-volatile configuration memory.

　　16384K bytes of processor board System flash (Read/Write)

　　--- System Configuration Dialog ---

　　Continue with configuration dialog? [yes/no]: n

　　Press RETURN to get started!

　　Router>

　　看这里进入系统之后 直接就进入了用户模式 没要密码

　　Router>en

　　Router#copy start run

　　Destination filename [running-config]?

　　552 bytes copied in 0.416 secs (1326 bytes/sec)

　　ru1#

　　我们 输入enable 进入特权模式 输入命令 copy start run 从NVRAM 里面调用配置到内存中

　　下一步更换密码

　　ru1#conf t

　　Enter configuration commands, one per line. End with CNTL/Z.

　　ru1(config)#line console 0

　　ru1(config-line)#pass admin

　　ru1(config-line)#login

　　ru1(config-line)#exit

　　ru1(config)#line vty 0 4

　　ru1(config-line)#pass admin

　　ru1(config-line)#login

　　ru1(config-line)#exit

　　ru1(config)#enable pass admin

　　ru1(config)#enable secret admin

　　ru1(config)#service password-encryption

　　比如说我们将密码修改为admin 实验环境下 只采用这一个密码

　　下一步 更改寄存器值 恢复到正常的启动次序

　　ru1(config)#config-register 0x2102

　　下一步 保存配置到NVRAM里面

　　ru1(config)#exit

　　%SYS-5-CONFIG_I: Configured from console by console

　　ru1#copy run start

　　Destination filename [startup-config]?

　　Building configuration...

　　[OK]

　　ru1#

　　重启一下

　　ru1#rel

　　Proceed with reload? [confirm]

　　%SYS-5-RELOAD: Reload requested by console. Reload Reason: Reload Command.

　　System Bootstrap, Version 12.1(3r)T2, RELEASE SOFTWARE (fc1)

　　Copyright (c) 2000 by cisco Systems, Inc.

　　cisco 2621 (MPC860) processor (revision 0x200) with 60416K/5120K bytes of memory

　　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-I-M), Version 12.2(28), RELEASE SOFTWARE (fc5)

　　Technical Support: http://www.cisco.com/techsupport

　　Copyright (c) 1986-2005 by cisco Systems, Inc.

　　Compiled Wed 27-Apr-04 19:01 by miwang

　　cisco 2621 (MPC860) processor (revision 0x200) with 60416K/5120K bytes of memory

　　.

　　Processor board ID JAD05190MTZ (4292891495)

　　M860 processor: part number 0, mask 49

　　Bridging software.

　　X.25 software, Version 3.0.0.

　　2 FastEthernet/IEEE 802.3 interface(s)

　　2 Low-speed serial(sync/async) network interface(s)

　　32K bytes of non-volatile configuration memory.

　　16384K bytes of processor board System flash (Read/Write)

　　%LINK-5-CHANGED: Interface FastEthernet0/0, changed state to up

　　%LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0/0, changed state to up

　　%LINK-5-CHANGED: Interface FastEthernet0/1, changed state to up

　　%LINK-5-CHANGED: Interface FastEthernet0/0, changed state to administratively down

　　%LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0/0, changed state to down

　　%LINK-5-CHANGED: Interface FastEthernet0/1, changed state to administratively down

　　Press RETURN to get started!

　　User Access Verification

　　Password:

　　ru1>en

　　Password:

　　ru1#

　　最后解释一下 文中带下划线的为个人说明

　　阴影部分是必要的步骤 是要输入命令的