Специалист по безопасности.

Здравствуйте, на мой Linux сервер была совершена DDOS, обнаруженная хостинг провайдером.  Как выяснилось, текущий админ не силен в этом. Я бы хотел принять меры по предотвращения атак.

Вот описание по атаке:

Subject: Exploitable LDAP server attack
A public-facing device on your network appears to operate a LDAP service responding on port 389 that participated in a large-scale attack against a customer of ours, generating UDP responses to spoofed requests that claimed to be from the attack target.

Please consider re-configuring this server.

Example responses from the host during this attack are given below.
Date/timestamps (far left) are UTC.

2018-08-02 09:16:28.562742 IP 192.111.154.174.389 > 192.223.25.x.12429: UDP, length 2955
0x0000: 4500 05dc 50b6 2000 7711 985c c06f 9aae E...P...w..\.o..
0x0010: c0df 1901 0185 308d 0b93 dca4 3084 0000 ......0.....0...
0x0020: 0b6f 0201 0764 8400 000b 6604 0030 8400 .o...d....f..0..
0x0030: 000b 5e30 8400 0000 2604 0b63 7572 7265 ..^0....&..curre
0x0040: 6e74 5469 6d65 3184 0000 0013 0411 3230 ntTime1.......20
0x0050: 3138 18
2018-08-02 09:16:28.933353 IP 192.111.154.174.389 > 192.223.25.x.36821: UDP, length 2955
0x0000: 4500 05dc 50c6 2000 7711 984c c06f 9aae E...P...w..L.o..
0x0010: c0df 1901 0185 8fd5 0b93 7d5b 3084 0000 ..........}[0...
0x0020: 0b6f 0201 0764 8400 000b 6604 0030 8400 .o...d....f..0..
0x0030: 000b 5e30 8400 0000 2604 0b63 7572 7265 ..^0....&..curre
0x0040: 6e74 5469 6d65 3184 0000 0013 0411 3230 ntTime1.......20
0x0050: 3138 18
2018-08-02 09:16:29.064720 IP 192.111.154.174.389 > 192.223.25.x.12429: UDP, length 2955
0x0000: 4500 05dc 50cd 2000 7711 9845 c06f 9aae E...P...w..E.o..
0x0010: c0df 1901 0185 308d 0b93 dca3 3084 0000 ......0.....0...
0x0020: 0b6f 0201 0764 8400 000b 6604 0030 8400 .o...d....f..0..
0x0030: 000b 5e30 8400 0000 2604 0b63 7572 7265 ..^0....&..curre
0x0040: 6e74 5469 6d65 3184 0000 0013 0411 3230 ntTime1.......20
0x0050: 3138 18

(The final octet of our customer's IP address is masked in the above output because some automatic parsers become confused when multiple IP addresses are included. The value of that octet is "1".)