Re: local telnetd DoS

[signal11 () MEDIAONE NET (Signal 11)]

Zo0mer wrote:
> Hi,i found local DoS that Crash telnetd (tested on Slackware 4.0, RH 5.2)
> type
> telnet localhost | telnet localhost | telnet localhost ...... about 50 times
> result will be 'Connection Refused' , telnetd crash.

That's not a telnet DoS - you're hitting inetd's builtin connection limit.
The default is to shutdown the service if more than 40 instances are started
in a 60 second period.  *Any* service under inetd will halt if more than the max number of instances are started.

Change this line in inetd.conf:
telnet stream  tcp     nowait  root    /usr/sbin/tcpd  in.telnetd
To:
telnet  stream  tcp     nowait.256 root /usr/sbin/tcpd in.telnetd

And try your "DoS" again.


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