安全 - Linux的audit.log日志审计

Question

我在阿里云买了一台主机,然后最近发现数据库被删了.查看audit.log时候发现一些可疑IP的ssh远程登录.例如下面这些信息,是否可以断定被黑客入侵了.

type=USER_LOGIN msg=audit(1483695199.639:6342): pid=xxxxxxx uid=0 auid=xxxxxxx ses=xxxxxxx msg='op=login acct=xxxxxxx exe="/usr/sbin/sshd" hostname=? addr=xxxxxxx terminal=ssh res=failed'
type=USER_AUTH msg=audit(1483695199.643:6343): pid=xxxxxxx uid=0 auid=xxxxxxx ses=xxxxxxx msg='op=PAM:authentication grantors=? acct="?" exe="/usr/sbin/sshd" hostname=xxxxxxx addr=xxxxxxx terminal=ssh res=failed'
type=USER_AUTH msg=audit(1483695201.437:6344): pid=xxxxxxx uid=0 auid=xxxxxxx ses=xxxxxxx msg='op=password acct=xxxxxxx exe="/usr/sbin/sshd" hostname=? addr=xxxxxxx terminal=ssh res=failed'
type=USER_AUTH msg=audit(1483695201.749:6345): pid=xxxxxxx uid=0 auid=xxxxxxx ses=xxxxxxx msg='op=PAM:authentication grantors=? acct="?" exe="/usr/sbin/sshd" hostname=xxxxxxx addr=xxxxxxx terminal=ssh res=failed'
type=USER_AUTH msg=audit(1483695204.151:6346): pid=xxxxxxx uid=0 auid=xxxxxxx ses=xxxxxxx msg='op=password acct=xxxxxxx exe="/usr/sbin/sshd" hostname=? addr=xxxxxxx terminal=ssh res=failed'
type=USER_AUTH msg=audit(1483695204.464:6347): pid=xxxxxxx uid=0 auid=xxxxxxx ses=xxxxxxx msg='op=PAM:authentication grantors=? acct="?" exe="/usr/sbin/sshd" hostname=xxxxxxx addr=xxxxxxx terminal=ssh res=failed'
type=USER_AUTH msg=audit(1483695205.943:6348): pid=xxxxxxx uid=0 auid=xxxxxxx ses=xxxxxxx msg='op=password acct=xxxxxxx exe="/usr/sbin/sshd" hostname=? addr=xxxxxxx terminal=ssh res=failed'
type=CRYPTO_KEY_USER msg=audit(1483695206.255:6349): pid=28805 uid=0 auid=xxxxxxx ses=xxxxxxx msg='op=destroy kind=session fp=? direction=both spid=xxxxxxx suid=xxxxxxx rport=xxx laddr=xxxxxxx lport=22  exe="/usr/sbin/sshd" hostname=? addr=xxxxxxx terminal=? res=success'
type=CRYPTO_KEY_USER msg=audit(1483695206.256:6350): pid=28805 uid=0 auid=xxxxxxx ses=xxxxxxx msg='op=destroy kind=server fp=xxxxxxx direction=? spid=xxxxxxx suid=0  exe="/usr/sbin/sshd" hostname=? addr=xxxxxxx terminal=? res=success'
type=CRYPTO_KEY_USER msg=audit(1483695206.256:6351): pid=28805 uid=0 auid=xxxxxxx ses=xxxxxxx msg='op=destroy kind=server fp=xxxxxxx direction=? spid=xxxxxxx suid=0  exe="/usr/sbin/sshd" hostname=? addr=xxxxxxx terminal=? res=success'

Answer 1

Curious what does CRYPTO_KEY_USER mean? There are some very unfamiliar IPs in my logs, and the last one is success. Does it mean that I have been logged in?

Answer 2

It can basically be confirmed, and it should be entered into your machine through brute force

Nowadays, many hacker machines on the Internet blast the entire IP range 24 hours a day, scan for weak passwords and try to log in automatically, so try not to use weak passwords and limit the number of logins in a short period of time.

Answer 3

Consider ordinary users using public keys to log in, and prohibit password and root user login.