SSHD 보안
SSHD를 어쩔 수 없이 외부에 공개를 해야하는 경우, 반드시 보안처리를 해야한다. 예상하는 것보다 상당히 많은 해킹시도를 하기 때문이다. 최소한 아래 2가지 처리는 해주면 그나마 좀 낫지 않을까? 그러나, 가능하다면, SSHD 포트를 열어주지 말고, VPN을 이용하기 바란다.
- root 로그인 막기
# vi /etc/ssh/sshd_config PermitRootLogin no # /etc/init.d/sshd restart
- DenyHosts
- Install (CentOS)
# yum install denyhosts
- 동작 확인 : 어떤 IP를 통해서 로그인 실패하였는지 확인, 사실, denyhosts는 /var/log/secure 로그를 확인하여 처리하지만, lastb 로 확인하여도 그다지 상관없을 것이다.
# lastb -i root ssh:notty 123.140.148.160 Mon Jul 4 06:49 - 06:49 (00:00) root ssh:notty 123.140.148.160 Mon Jul 4 06:49 - 06:49 (00:00) root ssh:notty 123.140.148.160 Mon Jul 4 06:49 - 06:49 (00:00) root ssh:notty 123.140.148.160 Mon Jul 4 06:49 - 06:49 (00:00) root ssh:notty 123.140.148.160 Mon Jul 4 06:49 - 06:49 (00:00) root ssh:notty 178.18.19.114 Sun Jul 3 14:17 - 14:17 (00:00) root ssh:notty 178.18.19.114 Sun Jul 3 14:17 - 14:17 (00:00) root ssh:notty 178.18.19.114 Sun Jul 3 14:17 - 14:17 (00:00) root ssh:notty 178.18.19.114 Sun Jul 3 14:16 - 14:16 (00:00) root ssh:notty 178.18.19.114 Sun Jul 3 14:16 - 14:16 (00:00) root ssh:notty 178.18.19.114 Sun Jul 3 14:16 - 14:16 (00:00) root ssh:notty 211.214.218.118 Sun Jul 3 10:00 - 10:00 (00:00) root ssh:notty 211.214.218.118 Sun Jul 3 10:00 - 10:00 (00:00) root ssh:notty 193.253.228.193 Sun Jul 3 06:05 - 06:05 (00:00) root ssh:notty 193.253.228.193 Sun Jul 3 06:04 - 06:04 (00:00) wcostiga ssh:notty 195.70.27.20 Sun Jul 3 01:14 - 01:14 (00:00) wcostiga ssh:notty 195.70.27.20 Sun Jul 3 01:14 - 01:14 (00:00) root ssh:notty 221.10.252.53 Sun Jul 3 01:14 - 01:14 (00:00) jroyds ssh:notty 195.70.27.20 Sun Jul 3 01:14 - 01:14 (00:00) jroyds ssh:notty 195.70.27.20 Sun Jul 3 01:14 - 01:14 (00:00) root ssh:notty 221.10.252.53 Sun Jul 3 01:14 - 01:14 (00:00) cdimasci ssh:notty 195.70.27.20 Sun Jul 3 01:14 - 01:14 (00:00) cdimasci ssh:notty 195.70.27.20 Sun Jul 3 01:14 - 01:14 (00:00) root ssh:notty 221.10.252.53 Sun Jul 3 01:14 - 01:14 (00:00) goodrich ssh:notty 195.70.27.20 Sun Jul 3 01:14 - 01:14 (00:00) root ssh:notty 221.10.252.53 Sun Jul 3 01:14 - 01:14 (00:00) goodrich ssh:notty 195.70.27.20 Sun Jul 3 01:14 - 01:14 (00:00) root ssh:notty 221.10.252.53 Sun Jul 3 01:14 - 01:14 (00:00) btmp begins Sun Jul 3 01:14:34 2011
차단 등록된 IP 확인# cat /etc/hosts.deny # # hosts.deny This file describes the names of the hosts which are # *not* allowed to use the local INET services, as decided # by the '/usr/sbin/tcpd' server. # # The portmap line is redundant, but it is left to remind you that # the new secure portmap uses hosts.deny and hosts.allow. In particular # you should know that NFS uses portmap! sshd: 221.10.252.53 sshd: 195.70.27.20 sshd: 193.253.228.193 sshd: 211.214.218.118 sshd: 178.18.19.114 sshd: 123.140.148.160
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