在实际工作中碰到一款PIX
506的防火墙，由于密码设置时间久远，客户公司中已经无人知道设备的密码，查阅CISCO资料及网上资料后，将密码破解，问题得以解决。
以下是破解的准备工作及过程：
准备工作：根据PIX IOS的版本下载以下文件
The appropriate binary file, depending on the PIX software
version you run:
np70.bin(7.x and 8.0 release)
np63.bin(6.3 release)
np62.bin(6.2 release)
np61.bin(6.1 release)
np60.bin(6.0 release)
np53.bin(5.3 release)
np52.bin(5.2 release)
np51.bin (5.1
release)
np50.bin (5.0
release)
np44.bin (4.4
release)
nppix.bin (4.3
and earlier releases)
Note: You need to determine what .bin file to
use, which depends upon the PIX code that your PIX currently runs
irrespective of the BIOS version.
具体步骤：（PIX Without a Floppy Drive）
Complete these steps to recover your password:
Install a serial terminal or a PC with terminal emulation
software on the PIX console port.
Verify that you have a connection with the PIX, and that
characters are going from the terminal to the PIX, and from the PIX
to the terminal.
Note: Because you are locked out, you only see
a password prompt.
Immediately after you power on the PIX Firewall and the startup
messages appear, send a BREAK character or press
the ESC key. The monitor> prompt is
displayed. If needed, type ? (question mark) to
list the available commands.
Use the interface command to specify which
interface the ping traffic should use. For floppiless PIXes with
only two interfaces, the monitor command defaults
to the inside interface.
Use the address command to specify the IP
address of the PIX Firewall's interface.
Use the server command to specify the IP
address of the remote TFTP server containing the PIX password
recovery file.
Use the file command to specify the filename of
the PIX password recovery file. For example, the 5.1 release uses a
file named np51.bin.
If needed, enter the gateway command to specify
the IP address of a router gateway through which the server is
accessible.
If needed, use the ping command to verify
accessibility. If this command fails, fix access to the server
before continuing.
Use the tftp command to start the download.
As the password recovery file loads, this message is
displayed:
Do you wish to erase the passwords? [yn]y Passwords have been erased.
Note: If there are Telnet or consoleaaa authentication commands in version 6.2, the
system also prompts to remove these.
The default Telnet password after this process is "cisco." There
is no default enable password. Go into configuration mode and issue
the passwd your_password command to change your
Telnet password and the enable password
your_enable_password command to create an enable password,
and then save your configuration.
monitor>interface 0
0: i8255X @ PCI(bus:0 dev:13
irq:10)1: i8255X @ PCI(bus:0 dev:14 irq:7 ) Using 0: i82559 @
PCI(bus:0 dev:13 irq:10), MAC:
0050.54ff.82b9
monitor>address 10.21.1.99
address
10.21.1.99
monitor>server 172.18.125.3
server
172.18.125.3
monitor>file np52.bin
file
np52.bin
monitor>gateway 10.21.1.1
gateway
10.21.1.1
monitor>ping 172.18.125.3
Sending 5,
100-byte 0xf8d3 ICMP Echoes to 172.18.125.3, timeout is 4
seconds:!!!!!Success rate is 100 percent
(5/5)
monitor>tftp
tftp np52.bin@172.18.125.3 via
10.21.1.1...................................Received 73728 bytes
Cisco Secure PIX Firewall password tool (3.0) #0: Tue Aug 22
23:22:19 PDT 2000Flash=i28F640J5 @ 0x300BIOS Flash=AT29C257 @
0xd8000 Do you wish to erase the passwords? [yn] yPasswords have
been erased. Rebooting....说明：当我们直连的时候也就不存在网关的概念了。