Red Hat Bugzilla – Bug 30046
telnetd double echo in local echo mode
Last modified: 2007-04-18 12:31:50 EDT
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User-Agent: Mozilla/4.76 [en] (X11; U; Linux 2.2.17-8-HBS i686)
When telnetd is told "DONT ECHO" during Telnet option negotiations,
it appears that the pseudo terminal (pty) is not configured properly.
After a successful login, characters typed at a shell prompt appear
twice: once from the local Telnet client and once from the shell.
Other Unix operating systems do not exhibit this behavior. I've
tested SCO OpenServer 5.0.5 and IBM AIX 4.3.3.
This "double echo" bug is present in Red Hat Linux 6.1 with
telnet-0.10-31 and in Red Hat Linux 7.0 with telnet-server-0.17-7.
Steps to Reproduce:
1. You need a Telnet client set to echo locally. It must not allow
the server to echo.
2. Open a telnet connection to a Linux host. Enter your username and
password. You will see the password as you type it.
3. At the shell prompt, type something like "date". You will see
Could you please retry with:
Bonus: security fixes to the recently discovered vulnerabilities