topic Block Telnet in Network Security

Block Telnet

Waheed Bahaduri — Sun, 10 Mar 2019 12:59:08 GMT

Hello Experts,

I want to create a custom-signature to block all TELNET traffic going across my IOS IPS. I tried alot but it didnt work for me. i created a sig with String-Tcp engine > added regex and telnet port=23 but it does not work.

can any one help me, plz ?

Block Telnet

Seeker123_2 — Thu, 20 Jun 2013 09:27:44 GMT

Hope that this suites you.

http://www.cisco.com/en/US/tech/tk648/tk361/technologies_configuration_example09186a0080100548.shtml#denytelnettraffic

Post something if you have some doubts.

Source: http://www.cisco.com/en/US/tech/tk648/tk361/technologies_configuration_example09186a0080100548.shtml#intro

Best Regards

Hugo Rodrigues

Block Telnet

Imran Ahmad — Thu, 20 Jun 2013 17:26:36 GMT

What you have posted is blocking telnet through normal router ios . but my question was how to block telnet through IOS IPS.

Block Telnet

mark.barrett — Thu, 20 Jun 2013 21:24:36 GMT

Try using Atomic IP engine, for any packet using TCP/23 drop the packet.

There's also some signatures which detect Telnet over non-standard ports which you might consider turning on.

Block Telnet

Imran Ahmad — Sat, 22 Jun 2013 16:07:28 GMT

I used Atomic ip engine aswell, but that is also not working. i tried droping all packets for TCP/23 but it is not blocking telnet traffic. but on other hand if i try blocking the whole ip then telnet will be blocked. but if i try blocking only port tcp/23 it does not get any effect

any help, this is a ccie lab question and i have to work it out asap