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访问列表防御 1.创建访问列表 access-list 101 deny udp any any eq 1434 access-list 101 permit ip any any 2.匹配访问列表和数据包长度 class-map match-all slammer_worm match access-group 101 match packet length min 404 max 404 3.丢弃所匹配的数据包 policy-map drop-slammer-worm class slammer_worm police 1000000 31250 31250 conform-action drop exceed-action drop violate-action drop NBAR 1. Create custom protocol ip nbar port-map custom-01 udp 1434 2. Create class-map class-map match-all slammer_worm match protocol custom-01 match packet length min 404 max 404 3. Use class-based policing to drop the matching packets at the ingress interface policy-map drop-slammer-worm class slammer_worm police 1000000 31250 31250 conform-action drop exceed-action drop violate-action drop NetFlow Router# config t Router# (config) interface serial 0/1 Router#(config-if) ip route-cache flow Router#(config-if) exit Router#(config) exit Router# 输出统计表 Router# (config) ip flow-export 192.168.155.1 700 To view NetFlow statistics for port 1434: Router# show ip cache flow | include 059A CAR Router# (config) access-list 150 deny udp any any eq 1434 Router# (config) access-list 150 permit ip any any Router# (config) interface fastEthernet 0/0 Router# (config-if) rate-limit input access-group rate-limit 150 8000 1500 20000 conform-action drop exceed-action drop Router# (config-if) exit Router# (config) exit Router# ACL补充 access-list 115 deny udp any any eq 1434 access-list 115 permit ip any any int ip access-group 115 in ip access-group 115 out 注意,如果你想追踪来源,最好使用netflow,而不要使用log。 病毒发送大量随机地址,如果路由器接口使用了“ICMP unreachable”命令的话,对这些大量的无效地址响应将导致路由器性能下降。因此,推荐使用以下命令: Router(config)# interface Router(if-config)# no ip unreachables ICMP unreachable 的补充 如果某些情况,如IP 隧道(tunnel)必须使用ICMP unreachable 命令,则推荐使用 Router(config)# ip icmp rate-limit unreachable 6500 上防御 set security acl ip WORM deny udp any eq 1434 any set security acl ip WORM deny udp any any eq 1434 set security acl ip WORM permit any commit security acl WORM set security acl map WORM 查看 show security acl info all CatOS SUPII 和 MLS CatOS SUPII 和 MLS 源码: switch> (enable) sh mls statistics entry ip Last Used Destination IP Source IP Prot DstPrt SrcPrt Stat-Pkts Stat-Bytes 10.81.176.91 172.16.34.35 UDP 1434 2776 0 0 172.31.171.82 172.16.34.35 UDP 1434 2776 0 0 168.192.57.204 172.16.188.61 UDP 1434 3460 1 404 172.17.136.55 172.16.34.135 UDP 1434 2917 0 0 从上面的显示我们可以发现,MLS可以帮助我们找到内部受感染主机 PIX access-list acl_out permit udp any host eq 1434 或者 conduit permit udp any any eq 1434
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