[求助] 这些日志都是什么意思？

xiaoxiao0

Jul 22 19:35:31 www sshd[7573]: pam_unix(sshd:auth): authentication failure; logname= uid=0 euid=0 tty=ssh ruser= rhost=123.138.37.68  user=root
Jul 22 19:35:33 www sshd[7573]: Failed password for root from 123.138.37.68 port 50792 ssh2
Jul 22 11:35:38 www sshd[7574]: Received disconnect from 123.138.37.68: 11: Bye Bye
Jul 22 19:35:44 www sshd[7576]: Did not receive identification string from 123.138.37.68
Jul 22 11:36:37 www sshd[7579]: Connection closed by 123.138.37.68
Jul 22 20:17:20 www sudo:    wdcpu : TTY=unknown ; PWD=/www/wdlinux/wdcp/sys ; USER=root ; COMMAND=/www/wdlinux/wdphp/bin/php /www/wdlinux/wdcp/task/wdcp_sv.php
Jul 22 20:17:27 www sudo:    wdcpu : TTY=unknown ; PWD=/www/wdlinux/wdcp/sys ; USER=root ; COMMAND=/www/wdlinux/wdphp/bin/php /www/wdlinux/wdcp/task/wdcp_sv.php
Jul 22 20:18:11 www sudo:    wdcpu : TTY=unknown ; PWD=/www/wdlinux/wdcp/sys ; USER=root ; COMMAND=/www/wdlinux/wdphp/bin/php /www/wdlinux/wdcp/task/wdcp_sr.php

文件太多，超过限制，所以作为附件上传，老大帮忙看下，是不是被攻击或者有人登录服务器

admin

ssh那些应该是一些猜解机了

wdcpu这些是后台调用的