本主题介绍如何配置 TCP fin-no-ack 攻击检测。设置了 FIN 标志但未设置 ACK 标志的 TCP 报头是异常的 TCP 行为。
要启用没有 ACK 位 IDS 选项的 FIN 位检测：
- 配置接口并为接口分配 IP 地址。
[edit]
user@host# set interfaces ge-0/0/1 unit 0 family inet address 192.0.2.0/24
user@host# set interfaces ge-0/0/3 unit 0 family inet address 198.51.100.0/24
- 配置安全区域 trustZone 并为 untrustZone 其分配接口。
[edit]
user@host# set security zones security-zone trustZone host-inbound-traffic system-services all
user@host# set security zones security-zone trustZone host-inbound-traffic protocols all
user@host# set security zones security-zone trustZone interfaces ge-0/0/1.0
user@host# set security zones security-zone untrustZone host-inbound-traffic system-services all
user@host# set security zones security-zone untrustZone host-inbound-traffic protocols all
user@host# set security zones security-zone untrustZone interfaces ge-0/0/3.0
- 配置从 untrustZone 到 trustZone的安全策略。
[edit]
user@host# set security policies from-zone untrustZone to-zone trustZone policy policy1 match source-address any
user@host# set security policies from-zone untrustZone to-zone trustZone policy policy1 match destination-address any
user@host# set security policies from-zone untrustZone to-zone trustZone policy policy1 match application any
user@host# set security policies from-zone untrustZone to-zone trustZone policy policy1 then permit
user@host# set security policies default-policy deny-all
- 配置安全屏幕并将其附加到 untrustZone。
[edit]
user@host# set security screen ids-option untrustScreen tcp fin-no-ack
user@host# set security zones security-zone untrustZone screen untrustScreen
user@host# set security screen ids-option untrustScreen alarm-without-drop
- 配置 syslog。
[edit]
user@host# set system syslog file syslog any any
user@host# set system syslog file syslog archive size 10000000
user@host# set system syslog file syslog structured-data
user@host# set security policies from-zone untrustZone to-zone trustZone policy policy1 then log session-init
user@host# set security policies from-zone untrustZone to-zone trustZone policy policy1 then log session-close
- 提交配置。
