However, many network equipment providers include light-weight Telnet systems that have not been adequately checked. Likewise, Telnet services for Windows frequently do not have enough security checks to prevent this problem. Defense Look at the list below to see if you have products that are vulnerable to these attacks. If so, download a patch from the vendor. Also, Telnet is an extremely dangerous protocol to leave exposed to the Internet.
Hackers frequently scan for it .
The username and password are passed across the network in clear-text, so they are easy to sniff from the wire. Telnet exploits Other exploits against the Telnet service. It will crash if the login name is more than 3090 characters. Buffer overflow in BFTelnet allows remote attackers to cause a denial of service via a long username. Buffer overflow in GoodTech Telnet Server NT allows remote users to cause a denial of service via a long login name.