Trivial mSQL/MySQL DoS method?

Stunt Pope (markjr@SHMOOZE.NET)
Thu, 26 Mar 1998 13:36:19 -0500

I noticed this awhile ago and meant to mention it, but then I forgot. (Until
last night when someone portscanned one of my servers and this behaviour
exhibited itself again.)

I have tested this on mSQL 1.0.16 and MySQL 3.20.20 on Slackware 2.0.27 and
the MySQL additionally on FreeBSD 2.2.2-current. (This has not been tested
on mSQL2.x)

It seems that if one wants to bring a website that relies heavily on mSQL or
MySQL to it's knees, simply telnet to the port the server listens on (1112
for mSQL or 3333 for MySQL) and then just sit there, forget about it.

Nothing on the server will be able to query any of the databases. The
admin shutdown or reload commands will hang, etc. As long as someone
keeps the null connection open to the SQL server's port, the only way
to resume database operations is to kill the parent process and restart
the daemon.

This seems to work regardless of what's in the acl files or tables.

A site using mod_auth_msql or mod_auth_mysql would be especially
inconvenienced.

-mark

---
Mark Jeftovic                   aka: mark jeff or vic, stunt pope.
markjr@shmOOze.net              http://www.shmOOze.net/~markjr
Private World's BOFH            http://www.PrivateWorld.com
irc: L-bOMb                     Keep `em Guessing