On Thu, 2005-04-07 at 09:14 +0300, Dotan Cohen wrote: > As I'm still new to linux I like to open things and see what they are > / do. So I opened the KDE System Logs program, clicked on over to > Security logs, and found a bunch of these: > > Apr 4 02:15:03 localhost sshd[26567]: Failed password for invalid > user test from ::ffff:219.238.239.10 port 3429 ssh2 This is a script kiddie trying to crack passwords on your ssh server. > and these: > > Apr 5 04:47:24 localhost sshd[7287]: reverse mapping checking > getaddrinfo for h169-210-68-8.adcast.com.tw failed - POSSIBLE BREAKIN > ATTEMPT! This is because reverse DNS for 210.68.8.169 (source of one of the script kiddie attacks) points to the hostname h169-210-68-8.adcast.com.tw but that name does not resolve. Not terribly uncommon with incompetent ISPs. > and many more like it. Is this something to worry about? Yes it is, but it's nothing personal. Everyone running a ssh server that isn't firewalled off except for specific IPs is probably getting them. I know I am. Suggestions: 1. Disable root logins in ssh (you can still log in as a regular user and use "su") by putting "PermitRootLogin no" in /etc/ssh/sshd_config. 2. Make sure you use strong passwords for *all* accounts. 3. Consider turning off password authentication altogether and using certificates instead. > Chkrootkit > didn't find anything suspicious, so that makes me feel a little > better, but as I am unable to start firestarter I am a little nervous. > > By the way, what is the difference between chkrootkit and chkrootkitX? > They both run in the terminal (I thought that chkrootkitX would open > up in a gui or something). Don't know; I've never used chkrootkit. > Is it unsafe to put a copy of the log on my site and post a link to it > here? it spans about 1500 lines, so I do not want to email it to the > list. Probably fairly safe but not very useful. Paul. -- Paul Howarth <paul@xxxxxxxxxxxx>
