Optimize user security of the UbuntuServer System

Article Title: Security Optimization Methods for users of the deletuserver system. Linux is a technology channel of the IT lab in China. Including desktop applications, Linux system management, kernel research, embedded systems and open-source systems. After installing LAMP Server in Ubuntu server, Ubuntu adds unnecessary users to the system, excessive users leave the possibility for hackers to obtain the shell. disabling unnecessary User shell permissions can reinforce the security of Ubuntu services to a certain extent.
　
After the installation is complete, the default/etc/passwd file content is as follows:
　
QUOTE:
　
Root: x: 0: 0: root:/bin/bash
　
Daemon: x: 1: 1: daemon:/usr/sbin:/bin/sh
　
Bin: x: 2: 2: bin:/bin/sh
　
Sys: x: 3: 3: sys:/dev:/bin/sh
　
Sync: x: 4: 65534: sync:/bin/sync
　
Games: x: 5: 60: games:/usr/games:/bin/sh
　
Man: x: 6: 12: man:/var/cache/man:/bin/sh
　
Lp: x: 7: 7: lp:/var/spool/lpd:/bin/sh
　
Mail: x: 8: 8: mail:/var/mail:/bin/sh
　
News: x: 9: 9: news:/var/spool/news:/bin/sh
　
Uucp: x: 10: 10: uucp:/var/spool/uucp:/bin/sh
　
Proxy: x: 13: 13: proxy:/bin/sh
　
Www-data: x: 33: 33: www-data:/var/www:/bin/sh
　
Backup: x: 34: 34: backup:/var/backups:/bin/sh
　
List: x: 38: 38: Mailing List Manager:/var/list:/bin/sh
　
Irc: x: 39: 39: ircd:/var/run/ircd:/bin/sh
　
Nobody: x: 65534: 65534: nobody:/nonexistent:/bin/sh
　
Syslog: x: 101: 102:/home/syslog:/bin/false
　
Klog: x: 102: 103:/home/klog:/bin/false
　
Mysql: x: 103: 104: MySQL Server,:/var/lib/mysql:/bin/false
　
Admin: x: 1000: 1000: Administrator,:/home/admin:/bin/bash
　
The specific content varies depending on the services selected for installation. Ubuntu creates more than 20 accounts by default. Most users do not know the specific purpose of these accounts. Several accounts are generally unnecessary for a web server, you can disable logon to these accounts by changing the shell (/bin/false ):
　
QUOTE:
　
Root: x: 0: 0: root:/bin/bash
　
Daemon: x: 1: 1: daemon:/usr/sbin:/bin/sh
　
Bin: x: 2: 2: bin:/bin/sh
　
Sys: x: 3: 3: sys:/dev:/bin/sh
　
Sync: x: 4: 65534: sync:/bin/sync
　
Games: x: 5: 60: games:/usr/games:/bin/false
　
Man: x: 6: 12: man:/var/cache/man:/bin/sh
　
Lp: x: 7: 7: lp:/var/spool/lpd:/bin/false
　
Mail: x: 8: 8: mail:/var/mail:/bin/false
　
News: x: 9: 9: news:/var/spool/news:/bin/false
　
Uucp: x: 10: 10: uucp:/var/spool/uucp:/bin/false
　
Proxy: x: 13: 13: proxy:/bin/sh
　
Www-data: x: 33: 33: www-data:/var/www:/bin/sh
　
Backup: x: 34: 34: backup:/var/backups:/bin/sh
　
List: x: 38: 38: Mailing List Manager:/var/list:/bin/false
　
Irc: x: 39: 39: ircd:/var/run/ircd:/bin/false
　
Nobody: x: 65534: 65534: nobody:/nonexistent:/bin/false
　
Syslog: x: 101: 102:/home/syslog:/bin/false
　
Klog: x: 102: 103:/home/klog:/bin/false
　
Mysql: x: 103: 104: MySQL Server,:/var/lib/mysql:/bin/false
　
Admin: x: 1000: 1000: Administrator,:/home/admin:/bin/bash
　
Of course, if the service is needed, do not change the shell.