Easy solution to password forgetting switch password cracking

Vswitches are still commonly used, so I have studied some questions about vswitch password cracking. I will share them with you here, hoping they will be useful to you. As we all know, both vswitches and vrouters require certain security guarantees. That is to say, we need to configure a reasonable password for them in a timely manner. What should we do if this password is forgotten? I have met this time. Due to job transfer, the former network administrator left the department, but set a password on the switch, and did not tell me the network administrator who took over. What should we do? Sending it back to the vendor for switch password cracking is too troublesome.

I. Network Environment:

The company uses a 3500 series vswitch with a specific model of 3548) to connect a Huawei 2621 vro to the vswitch and access the Internet through optical fiber cables of China Telecom. The actual situation is that the vswitch 3548 was set by the previous network administrator and didn't tell me. Therefore, switch password cracking becomes the core of this article.

2. preparations:

Because the entire work needs to be disconnected, after all, operations such as restarting the switch are involved, so the time is am after work. In addition, because password cracking and other such operations must be set using the CONSOLE line, the location can only be a central data center. I have found all the tools related to devices up to 3548, including installation instructions and CONSOLE control lines.

Iii. Actual password cracking:

According to my previous experience, the usage and Operation Command statements of all devices should be similar to those of CISCO devices. Therefore, I thought it would be easy to crack the password of CISCO devices. Who knows the difference is not small. Generally, CISCO devices use the configuration register to crack passwords. The configuration register does not exist in the real-time switch. After querying the information, we found that the original real-time switch was used to modify the Super Terminal Configuration to crack the switch password.

Step 1: connect the CONSOLE control line of the real-time switch to the CONSOLE management interface of the device.

Step 2: disconnect another line of control on the CONSOLE to the COM serial port of the notebook used for debugging by the network administrator.

Step 3: Go to the desktop of the notebook system and click Start> All Programs> accessories> communication> Super Terminal ". 1)

Step 4: after starting the Super Terminal of the system, we can name the new connection. 2)

Step 5: select the port that you just connected to using the CONSOLE control line from the drop-down menu in the "use during connection" Area of the connection settings. For example, COM1 port. 3)

Step 6: In the COM1 property settings window, configure the connection parameters. Generally, we normally connect to a vswitch using 9600 bits per second, 8 data bits, no parity check, 1 Stop bits, and no data flow control. However, if you want to crack the switch password, you need to modify these values. Set the serial port speed of the PC Super Terminal to 57600, and set the speed to the same as that written above.

Step 7: Use the terminal to connect to the vswitch, and then turn on the power of the vswitch. After the vswitch is started, immediately press the "ESC" Key multiple times to enter the monitoring mode of the vswitch. Multiple options are displayed on the terminal interface, including some basic initialization settings.

TIPS: At the beginning, I did not succeed in following step 7. The Super Terminal interface always displays many "...". Later, it was discovered that the switch had to be connected to the Super Terminal before it could be powered on. If the switch was first connected to the Super Terminal, it would not be able to enter the monitoring mode.

Step 8: Upload the configuration file config. text to the notebook used by the network administrator according to the menu prompt, and then delete the configuration file Config. text on the switch.

Step 9: Open the downloaded config. text file in the system hard disk in the notebook and run the following statement: enable secret level 1 5! E, 1u _; C9 &-8U0H, enable secret level 15 5 * r_1u _; C3vW8U0H, delete, save, and exit.

Step 10: Download the modified config. text in the notebook to the switch according to the prompt in the switch monitoring mode.

Step 2: Set the serial port speed of the Super Terminal of the notebook to 11th again, and keep the default parameters for others. After the vswitch is powered on and restarted, you can go to the vswitch configuration page and find that you can reconfigure the vswitch password, including the management password for remote TELNET and the privilege password of the local machine. After that, the switch password will be changed to the one you just configured, while other configurations will remain unchanged and will not affect any usage.

TIPS: in actual use, I found that the upload and download functions in the monitoring mode of the 3550 switch are not stable, and transmission failures often occur. Therefore, the author simply deletes config. text in monitoring mode, and then restarts the switch to reconfigure all the switch information. This situation applies to the fact that the vswitch does not have many configurations and is not complex. In addition, the network administrator must be familiar with the setting statements.

Summary:

After the actual switch password cracking operation, the author once again understands that for the routing switch device, the operating procedures and steps of different vendors are absolutely different, even if the command statements are similar, they are quite different in other advanced operations. Therefore, all the content introduced in this article is only for real-time routers and switches. If you encounter other devices, you need to use other methods to solve them.