检查Linux服务器是否被攻击的常用命令及方法

1. 使用last命令查看登录服务器的用户记录。

[root@centos8 ~]# last
rusking  pts/2        192.168.1.102    Sun Aug 23 18:38   still logged in
rusking  pts/2        192.168.1.102    Sun Aug 23 18:08 - 18:14  (00:05)
rusking  pts/2        192.168.1.102    Sun Aug 23 18:05 - 18:07  (00:01)
rusking  pts/2        192.168.1.102    Sun Aug 23 17:38 - 17:58  (00:19)
rusking  pts/2        192.168.1.102    Sun Aug 23 16:41 - 17:38  (00:56)
rusking  pts/1        192.168.1.82     Sun Aug 23 16:33   still logged in
root     web console                   Sun Aug 23 15:03 - 15:18  (00:15)
rusking  pts/0        192.168.1.82     Sun Aug 23 14:49   still logged in
root     tty1                          Sun Aug 23 14:49   still logged in
reboot   system boot  4.18.0-193.14.2. Sun Aug 23 14:48   still running
rusking  pts/0        192.168.1.82     Sat Aug 15 09:07 - 18:30 (2+09:22)
rusking  tty1                          Sat Aug 15 09:07 - crash (8+05:40)
reboot   system boot  4.18.0-193.14.2. Sat Aug 15 09:06   still running

2. 使用who命令查看当前登录的用户。

[root@centos8 ~]# who -a
           system boot  2020-08-23 14:48
root     + tty1         2020-08-23 14:49 03:59        2059
rusking  + pts/0        2020-08-23 14:49 00:51        3193 (192.168.1.82)
           web console  2020-08-23 15:18              9190 id=919   term=0 exit=0
rusking  + pts/1        2020-08-23 16:33   .          3193 (192.168.1.82)
rusking  + pts/2        2020-08-23 18:38 00:10       96080 (192.168.1.102)
[root@centos8 ~]# 

3.查看命令执行记录 。
# tail -n 200 ~/.bash_history | more #查看当前帐户的操作命令。-n 200显示最近200条记录。

# tail -n 200 /home/rusking/.bash_history | more #查看指定用户名为rusking的操作命令记录。 可以将rusking替换成其它用户。

4. 查看最近2天修改过的文件
# find /etc /var -mtime -2

5.使用netstat 命令查看本机各端口连接情况。
#netstat -aplunt 常用命令,关注LISTEN和ESTABLISHED情况。

[root@centos8 ~]# netstat -aplunt
Active Internet connections (servers and established)
Proto Recv-Q Send-Q Local Address           Foreign Address         State       PID/Program name    
tcp        0      0 0.0.0.0:9090            0.0.0.0:*               LISTEN      1/systemd           
tcp        0      0 0.0.0.0:5355            0.0.0.0:*               LISTEN      1972/systemd-resolv 
tcp        0      0 0.0.0.0:111             0.0.0.0:*               LISTEN      1/systemd           
tcp        0      0 192.168.122.1:53        0.0.0.0:*               LISTEN      2400/dnsmasq        
tcp        0      0 127.0.0.1:631           0.0.0.0:*               LISTEN      1415/cupsd          
tcp        0      0 0.0.0.0:8888            0.0.0.0:*               LISTEN      1414/sshd           
tcp        0    248 192.168.1.101:8888      192.168.1.82:54949      ESTABLISHED 3193/sshd: rusking  
tcp        0      0 192.168.1.101:8888      192.168.1.102:53426     ESTABLISHED 96080/sshd: rusking 
udp        0      0 0.0.0.0:45742           0.0.0.0:*                           1029/avahi-daemon:  
udp        0      0 0.0.0.0:5353            0.0.0.0:*                           1029/avahi-daemon:  
udp        0      0 0.0.0.0:5355            0.0.0.0:*                           1972/systemd-resolv 
udp        0      0 192.168.122.1:53        0.0.0.0:*                           2400/dnsmasq        
udp        0      0 127.0.0.53:53           0.0.0.0:*                           1972/systemd-resolv 
udp        0      0 0.0.0.0:67              0.0.0.0:*                           2400/dnsmasq        
udp        0      0 0.0.0.0:111             0.0.0.0:*                           1/systemd          

6. 使用lsof命令查看打开的文件。

# lsof -i

# lsof -p pid

[root@centos8 ~]# lsof -i
COMMAND     PID            USER   FD   TYPE DEVICE SIZE/OFF NODE NAME
systemd       1            root   42u  IPv4  18941      0t0  TCP *:sunrpc (LISTEN)
systemd       1            root   43u  IPv4  18942      0t0  UDP *:sunrpc 
systemd       1            root   51u  IPv4  22690      0t0  TCP *:websm (LISTEN)
rpcbind     960             rpc    4u  IPv4  18941      0t0  TCP *:sunrpc (LISTEN)
rpcbind     960             rpc    5u  IPv4  18942      0t0  UDP *:sunrpc 
avahi-dae  1029           avahi   15u  IPv4  25088      0t0  UDP *:mdns 
avahi-dae  1029           avahi   16u  IPv4  25099      0t0  UDP *:45742 
sshd       1414            root    5u  IPv4  27123      0t0  TCP *:ddi-tcp-1 (LISTEN)
cupsd      1415            root   10u  IPv4  27305      0t0  TCP localhost:ipp (LISTEN)
systemd-r  1972 systemd-resolve   12u  IPv4  29589      0t0  UDP *:hostmon 
systemd-r  1972 systemd-resolve   13u  IPv4  29590      0t0  TCP *:hostmon (LISTEN)
systemd-r  1972 systemd-resolve   16u  IPv4  29593      0t0  UDP 127.0.0.53:domain 
dnsmasq    2400         dnsmasq    3u  IPv4  32237      0t0  UDP *:bootps 
dnsmasq    2400         dnsmasq    5u  IPv4  32240      0t0  UDP centos8.test.com:domain 
dnsmasq    2400         dnsmasq    6u  IPv4  32241      0t0  TCP centos8.test.com:domain (LISTEN)
sshd       3193            root    5u  IPv4  34113      0t0  TCP centos8.test.com:ddi-tcp-1->UltraPower:54949 (ESTABLISHED)
sshd       3210         rusking    5u  IPv4  34113      0t0  TCP centos8.test.com:ddi-tcp-1->UltraPower:54949 (ESTABLISHED)
sshd      96080            root    5u  IPv4 252937      0t0  TCP centos8.test.com:ddi-tcp-1->192.168.1.102:53426 (ESTABLISHED)
sshd      96083         rusking    5u  IPv4 252937      0t0  TCP centos8.test.com:ddi-tcp-1->192.168.1.102:53426 (ESTABLISHED)
[root@centos8 ~]# lsof -p 96083
COMMAND   PID    USER   FD   TYPE             DEVICE SIZE/OFF     NODE NAME
sshd    96083 rusking  cwd    DIR              253,0      265      128 /
sshd    96083 rusking  rtd    DIR              253,0      265      128 /
sshd    96083 rusking  txt    REG              253,0  1228192  3786429 /usr/sbin/sshd
sshd    96083 rusking  mem    REG              253,0   906648   640148 /usr/lib64/libnss_systemd.so.2
sshd    96083 rusking  mem    REG              253,0 10406312 34621674 /var/lib/sss/mc/initgroups
......

7. 使用ps命令查看当前系统中正在运行的进程信息。

#ps -aux  

[root@centos8 ~]# ps -aux | grep rusking
root        3193  0.0  0.3 161180 10768 ?        Ss   14:49   0:00 sshd: rusking [priv]
rusking     3197  0.0  0.3  93812  9400 ?        Ss   14:49   0:00 /usr/lib/systemd/systemd --user
rusking     3199  0.0  0.1 251456  3760 ?        S    14:49   0:00 (sd-pam)
rusking     3208  0.0  0.3 300224  9324 ?        Ssl  14:49   0:00 /usr/bin/pulseaudio --daemonize=no
rusking     3210  0.0  0.2 161180  6084 ?        S    14:49   0:01 sshd: rusking@pts/0,pts/1
rusking     3211  0.0  0.1  24696  5432 pts/0    Ss   14:49   0:00 -bash
rusking     3266  0.0  0.1  74292  4480 ?        Ss   14:49   0:00 /usr/bin/dbus-daemon --session --address=systemd: --nofork --nopidfile --systemd-activation --syslog-only
rusking    46209  0.0  0.1  24696  5220 pts/1    Ss   16:33   0:00 -bash
root       96080  0.0  0.3 161180 10760 ?        Ss   18:38   0:00 sshd: rusking [priv]
rusking    96083  0.0  0.1 161180  5352 ?        S    18:38   0:00 sshd: rusking@pts/2
rusking    96084  0.0  0.1  24712  5336 pts/2    Ss+  18:38   0:00 -bash
root      102735  0.0  0.0  12108  1072 pts/1    S+   18:55   0:00 grep --color=auto rusking

8. 使用top或htop命令查看进程对CPU/内存的消耗情况。

注意消耗CPU/内存较高的进程。

[root@centos8 ~]# top 
top - 18:56:58 up  4:08,  4 users,  load average: 0.00, 0.00, 0.00
Tasks: 145 total,   1 running, 144 sleeping,   0 stopped,   0 zombie
%Cpu(s):  0.2 us,  0.3 sy,  0.0 ni, 99.2 id,  0.0 wa,  0.2 hi,  0.2 si,  0.0 st
MiB Mem :   2834.8 total,   1845.2 free,    301.6 used,    688.0 buff/cache
MiB Swap:   3072.0 total,   3072.0 free,      0.0 used.   2356.1 avail Mem 

    PID USER      PR  NI    VIRT    RES    SHR S  %CPU  %MEM     TIME+ COMMAND                                                     
 103380 root      20   0   64536   4452   3768 R   0.3   0.2   0:00.01 top                                                         
      1 root      20   0  177912  11676   8100 S   0.0   0.4   0:11.04 systemd                                                     
      2 root      20   0       0      0      0 S   0.0   0.0   0:00.00 kthreadd                                                    
      3 root       0 -20       0      0      0 I   0.0   0.0   0:00.00 rcu_gp                                                      
      4 root       0 -20       0      0      0 I   0.0   0.0   0:00.00 rcu_par_gp                                                  
      6 root       0 -20       0      0      0 I   0.0   0.0   0:00.00 kworker/0:0H-kblockd                                        
      8 root       0 -20       0      0      0 I   0.0   0.0   0:00.00 mm_percpu_wq                                                
      9 root      20   0       0      0      0 S   0.0   0.0   0:00.25 ksoftirqd/0                                                 
     10 root      20   0       0      0      0 I   0.0   0.0   0:01.49 rcu_sched                                                   
     11 root      rt   0       0      0      0 S   0.0   0.0   0:00.03 migration/0                                                 
     12 root      rt   0       0      0      0 S   0.0   0.0   0:00.01 watchdog/0                                                  
     13 root      20   0       0      0      0 S   0.0   0.0   0:00.00 cpuhp/0                                                     
     14 root      20   0       0      0      0 S   0.0   0.0   0:00.00 cpuhp/1                                                     
     15 root      rt   0       0      0      0 S   0.0   0.0   0:00.01 watchdog/1                                                  
     16 root      rt   0       0      0      0 S   0.0   0.0   0:00.04 migration/1                                                 
     17 root      20   0       0      0      0 S   0.0   0.0   0:00.15 ksoftirqd/1                                                 
     19 root       0 -20       0      0      0 I   0.0   0.0   0:00.00 kworker/1:0H-kblockd    
...

9. 查看SSH登录日志。
centos/RHEL Linux查看Secure和audit日志。
/var/log/secure
关键字”Accepted password“

/var/log/audit/audit.log
关键字:”type=USER_AUTH“

其它LInux查看auto.log日志
/var/log/auth.log

10. 查看以下目录下是否有特殊文件。
# ls /tmp/ -la
# ls /dev/shm -la
# ls /var/tmp -la

11. 查看cronjob配置文件是否有异常的job

# crontab -l
# cat /etc/crontab
# ls /etc/cron 查看以下所有目录下是否有异常文件,以及这些文件的内容是否被修改。
cron.d/ cron.daily/ cron.deny cron.hourly/ cron.monthly/ crontab cron.weekly/

12. 使用nmap命令查看打开的端口
#nmap localhost 注意是否有异常开启的端口。

[root@centos8 ~]# nmap localhost
Starting Nmap 7.70 ( https://nmap.org ) at 2020-08-23 19:00 +04
Nmap scan report for localhost (127.0.0.1)
Host is up (0.0000080s latency).
Other addresses for localhost (not scanned): ::1
Not shown: 996 closed ports
PORT     STATE SERVICE
111/tcp  open  rpcbind
631/tcp  open  ipp
8888/tcp open  sun-answerbook
9090/tcp open  zeus-admin

Nmap done: 1 IP address (1 host up) scanned in 1.70 seconds

  

posted on 2020-08-23 23:03  遠離塵世の方舟  阅读(432)  评论(0编辑  收藏

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