Linux Server Hacked, Bandwidth Eating Machine...
 

Hi, I just put up my Mandrake 9.2 Server, its been running for about 3 weeks and its collocated at my school. According to the morning administrator it eats the students bandwidth so bad and lags them that they unplug me. I read the logs and I find that there has been people trying to gain access by FTP, TELNET... I also see MYSQL propogation worm was detected and caught I believe... anywayz I also get tons of CyberKit 2.2 ICMP pings. What Could be making my server eat bandwdith like that? What do I to stop my server from being hacked.. Its almost like its running a D O S Attack.

HELP this linux boy in bewilderment. :Pengy:

First off, if you want to be secure never run an FTP or Telnet server. Use SSH for file transfer and external logins. Setup an IP Tables firewall (there are a million and one how-to's on the net). What you want to do is block all ports other then the ones you are using (80 for HTTP probably, 22 for SSH, maybe others for SHTTP, IMAP-SSL, SMTP, whatever). Don't bind things like mysql to external ports unless you really need to (ie you connect to your database from outside your machine).

Also, make sure you run all you servers (like apache) under there own user. This way if somebody can figure out a way to exploit the program they have very limited ability to effect anything else.

ICMP CyberKit. blah blah is the Welchia/Nachi worm trying to propagate. Looks like your school has a lot more problems than just your Linux box, that's a Windows worm. No wonder the network is so slow.

Actually, were the pings going from your box or to your box? It could be that someone compromised your box and was trying to use it as a platform to scout the Windows machines for other potential vulnerabilities.

Sounds like you probably need to wipe and reinstall, this time be more concious of security. Don't install any software you don't need right now. Run the Mandrake update to make sure you get all the security patches available. Run a firewall (I think Shorewall comes with Mandrake) and configure it properly (plenty of tips for firewall configurations here). Actually, just search this forum for tips of system hardening. Check out unSpawn's security references, too. There are a ton.