Im Being DDOSED

riccardo123 · Mon Sep 22, 2014 1:27 am

Hi
I am new in this forum but i have a big problem. I work for a company and we have different websites hosted and o ther services.
I own a RB1100 ahx2 . In last week we have suffered a big ddos attack which was type of dns amplification attack.It consumed all by 30MB bandwidth and also my isp bandwidth. It was 1-2GB/s attack. After this i am beeing ddosed from all over the world on my webpage. I have tried all online solution for mikrotik to stop this ddos but cant. I have >10000 Unreplied connections even i have drop invalid packets. I have already configured syn flood attack defense,ddos attack defense on my firewall but still they are able to make my site "service unavaiable".

My setup is in short
2 WANS- 1LAN
All my servers are reachable from both wans.

I f anyone can help me with a complete bulletproff firewall i will be very thankfull.Im going crazy in last week.

my pubblic ip which is being ddosed is replaced with wan1
I have exported from terminal its a bit mesy and some rules are dissabled and comments are wrong because i have been experimenting a lot these nights,

 0 X ;;; Block dns
     chain=input action=drop protocol=udp src-address-list=!DNS Server 
     dst-port=53 

 1 X chain=input action=jump jump-target=syn-flood protocol=tcp 
     dst-address=wan1 

 2 X chain=syn-flood action=accept connection-limit=32,32 

 3 X chain=syn-flood action=add-src-to-address-list tcp-flags="" protocol=tcp 
     src-address-list=!LAN address-list=Dos_flood address-list-timeout=1d30m 

 4 X chain=input action=drop protocol=tcp dst-address=wan1 
     src-address-list=Dos_flood dst-port=80 

 5 X chain=forward action=drop protocol=tcp dst-address=wan1 
     src-address-list=invalid dst-port=80 

 6 X chain=input action=drop protocol=tcp dst-address=wan1 
     src-address-list=Dos_flood dst-port=80 

 7 X chain=forward action=reject reject-with=icmp-network-unreachable 
     connection-state=invalid protocol=tcp src-address=192.168.1.235 
     src-port=80 

 8 X ;;; Block dns
     chain=input action=drop protocol=tcp dst-address=wan1 
     src-address-list=ddoser2 dst-port=80 

 9 X ;;; Block dns
     chain=input action=jump jump-target=block-ddos2 connection-state=new 
     dst-address=wan1 in-interface=Itiran 2 

10 X ;;; Block dns
     chain=block-ddos2 action=return connection-state=new limit=10,10 

11 X ;;; Block dns
     chain=block-ddos2 action=return src-address-list=LAN 

12 X ;;; Block dns
     chain=block-ddos2 action=add-src-to-address-list address-list=ddoser2 
     address-list-timeout=40m 

13 X ;;; Block dns
     chain=input action=add-src-to-address-list tcp-flags=syn protocol=tcp 
     address-list=Dos_flood address-list-timeout=30m in-interface=Itiran 2 
     connection-limit=100,32 

14 X ;;; Block dns
     chain=input action=drop src-address-list=Dos_flood in-interface=Itiran 2 

15 X ;;; Bllokuar
     chain=input action=jump jump-target=block-ddos tcp-flags=syn 
     connection-state=new protocol=tcp dst-port=80 

16 X chain=input action=drop dst-address=wan1 src-address-list=ddoser 

17 X chain=forward action=drop dst-address=wan1 
     src-address-list=ddoser 

18 X chain=block-ddos action=return connection-state=new protocol=tcp 
     connection-limit=10,32 

19 X chain=block-ddos action=return src-address-list=LAN 
     dst-limit=50,50,src-and-dst-addresses/1m40s 

20 X chain=block-ddos action=add-dst-to-address-list address-list=ddosed 
     address-list-timeout=10h10m 

21 X chain=block-ddos action=add-src-to-address-list address-list=ddoser 
     address-list-timeout=10h10m 

22   chain=input action=drop connection-state=invalid 

23   chain=input action=accept connection-state=established 

24   chain=input action=accept connection-state=related 

25   ;;; Accept Established
     chain=forward action=drop connection-state=invalid 

26   ;;; Block dns
     chain=input action=add-src-to-address-list tcp-flags=syn 
     connection-state=new protocol=tcp address-list=blocksyn 
     address-list-timeout=30m connection-limit=5,24 

27   ;;; Block dns
     chain=input action=drop src-address-list=blocksyn 

28   ;;; Block dns
     chain=input action=tarpit protocol=tcp src-address-list=Black 

29   ;;; Block dns
     chain=input action=add-src-to-address-list protocol=tcp 
     address-list=Black address-list-timeout=23h30m connection-limit=10,32 

30   ;;; Accept Established
     chain=forward action=accept connection-state=established 

31   ;;; Accept Related
     chain=forward action=accept connection-state=related 

32   ;;; Block dns
     chain=input action=drop protocol=udp in-interface=Itiran 2 dst-port=53 

33   ;;; Block dns
     chain=input action=reject reject-with=icmp-network-unreachable 
     protocol=udp in-interface=Itiran 2 dst-port=80 

34   ;;; Block dns
     chain=input action=drop protocol=tcp in-interface=Itiran 2 dst-port=53 

35   ;;; Block dns
     chain=input action=drop protocol=udp in-interface=Primo dst-port=53 

36   ;;; Block dns
     chain=input action=drop protocol=tcp in-interface=Primo dst-port=53 

37 X ;;; Block dns
     chain=forward action=drop protocol=udp src-address-list=!Internet 
     dst-address-list=!DNS Server dst-port=53 

38 X ;;; Block dns
     chain=input action=drop protocol=udp src-address=23.0.0.0/8 dst-port=53 

39   ;;; Reject Spammer
     chain=forward action=drop protocol=tcp src-address-list=spammer 
     dst-port=25 

40   ;;; Block dns
     chain=input action=drop protocol=udp src-address-list=!DNS Server 
     in-interface=Itiran 2 src-port=53 

41   ;;; Block dns
     chain=forward action=drop protocol=udp dst-address-list=!DNS Server 
     out-interface=Itiran 2 dst-port=53 

42   ;;; Conficker
     chain=forward action=drop protocol=udp dst-port=135 

43   ;;; Conficker
     chain=forward action=drop protocol=tcp dst-port=135 

44   ;;; Conficker
     chain=forward action=drop protocol=tcp dst-port=4691 

45   ;;; Conficker
     chain=forward action=drop protocol=tcp dst-port=445 

46   ;;; Conficker
     chain=forward action=drop protocol=tcp dst-port=5933 

47   ;;; Conficker
     chain=forward action=drop protocol=tcp dst-port=139 

48   ;;; Conficker
     chain=forward action=drop protocol=udp dst-port=445 

49   ;;; Conficker
     chain=forward action=drop protocol=udp dst-port=138 

50   ;;; Conficker
     chain=forward action=drop protocol=udp dst-port=137 

51   ;;; Detect SMTP virus spammer
     chain=forward action=add-src-to-address-list protocol=tcp 
     src-address=!192.168.1.198 address-list=spammer address-list-timeout=1d 
     in-interface=LAN dst-port=25 

52 X ;;; Bllokuar - Baste live
     chain=forward action=drop protocol=tcp content=lottoalbania 

53 X ;;; Baste live
     chain=forward action=log protocol=tcp src-address=46.183.120.1 
     dst-port=23232 log-prefix="kom6" 

54 X ;;; Baste live
     chain=forward action=log src-address=192.168.1.194 out-interface=!LAN 
     log-prefix="xxxxxx" 

55 X ;;; Detect SMTP virus spammer
     chain=forward action=accept out-interface=ITIRANA 

56 X ;;; Detect SMTP virus spammer
     chain=forward action=accept out-interface=Primo 

57 X ;;; Detect SMTP virus spammer
     chain=forward action=drop 

58 X ;;; Detect SMTP virus spammer
     chain=forward action=log protocol=tcp src-address=192.168.1.83 
     log-prefix="VVVVVVV" 

59 X ;;; Detect SMTP virus spammer
     chain=forward action=log dst-address=192.168.1.253 log-prefix="aaaaaa" 

60 X chain=forward action=drop protocol=tcp src-address=192.168.1.65 
     content=youtube 

61   ;;; Hapur - Reject Spammer
     chain=forward action=drop protocol=tcp src-address-list=Dos_flood 

62 X ;;; Bllokuar -  Reject Spammer
     chain=forward action=drop protocol=udp src-address=188.138.96.47 
     dst-port=5060 

63 X chain=forward action=log protocol=tcp in-interface=LAN dst-port=25 
     log-prefix="email" 

64   ;;; fb
     chain=forward action=drop protocol=tcp src-address-list=!Perjashtime 
     layer7-protocol=fb dst-port=80 

65   ;;; fb
     chain=forward action=drop protocol=tcp src-address-list=!Perjashtime 
     dst-address-list=fejsbuk 

66 X ;;; Bllokuar - Ultra Surf Servers
     chain=input action=drop protocol=tcp dst-address=91.210.138.162 
     src-address-list=UltraSurfServers in-interface=ITIRANA 

67 X chain=input action=drop protocol=tcp dst-address=213.207.45.34 
     src-address-list=UltraSurfServers in-interface=Primo 

68 X chain=output action=drop protocol=tcp src-address=91.210.138.162 
     dst-address-list=UltraSurfServers out-interface=ITIRANA 

69 X chain=output action=drop protocol=tcp src-address=213.207.45.34 
     dst-address-list=UltraSurfServers out-interface=Primo 

70 X ;;; ultrasurf
     chain=forward action=drop protocol=tcp src-address-list=UltraSurfUsers 

71 X ;;; drop proxy
     chain=forward action=drop protocol=tcp src-address-list=UltraSurfUsers 
     dst-address-list=UltraSurfProxies 

72   ;;; Drop FTP
     chain=input action=drop protocol=tcp src-address-list=!LAN dst-port=21 

73   ;;; Drop SSH
     chain=input action=drop protocol=tcp src-address-list=!LAN dst-port=22 

74   ;;; Drop Telnet
     chain=input action=drop protocol=tcp src-address-list=!LAN dst-port=23 

75   ;;; Shto FTP Src
     chain=input action=add-src-to-address-list protocol=tcp 
     src-address-list=!LAN address-list=ftp_blacklist address-list-timeout=2d 
     dst-port=21 

76   ;;; Shto SSH Src
     chain=input action=add-src-to-address-list protocol=tcp 
     src-address-list=!LAN address-list=ssh_blacklist address-list-timeout=2d 
     dst-port=22 

77   ;;; Shto telnet Src
     chain=input action=add-src-to-address-list protocol=tcp 
     src-address-list=!LAN address-list=telnet_blacklist 
     address-list-timeout=2d dst-port=23 

78   ;;; Hapur - Port scanners list
     chain=forward action=add-src-to-address-list protocol=tcp psd=21,3s,3,1 
     src-address-list=!LAN address-list=port_scanners address-list-timeout=2d 

79   ;;; NMAP FIN Stealth Scan
     chain=forward action=add-src-to-address-list 
     tcp-flags=fin,!syn,!rst,!psh,!ack,!urg protocol=tcp 
     src-address-list=!LAN address-list=port_scanners address-list-timeout=2w 

80   ;;; FIN/PSH/URG scan
     chain=forward action=add-src-to-address-list 
     tcp-flags=fin,psh,urg,!syn,!rst,!ack protocol=tcp src-address-list=!LAN 
     address-list=port_scanners address-list-timeout=2w 

81   ;;; NMAP NULL Scan
     chain=forward action=add-src-to-address-list 
     tcp-flags=!fin,!syn,!rst,!psh,!ack,!urg protocol=tcp 
     src-address-list=!LAN address-list=port_scanners address-list-timeout=2w 

82   ;;; Drop Dos list
     chain=input action=tarpit protocol=tcp src-address-list=Dos_flood 
     connection-limit=3,32 

83   ;;; Shto Dos Host
     chain=input action=add-src-to-address-list protocol=tcp 
     src-address-list=!LAN address-list=Dos_flood address-list-timeout=1d 
     connection-limit=200,32 

84   ;;; Drop Port scaners
     chain=forward action=drop src-address-list=port_scanners 

85   ;;; Drop Viruses
     chain=forward action=drop protocol=tcp dst-port=135-139 

86   chain=forward action=drop protocol=udp dst-port=135-139 

87   chain=forward action=drop protocol=tcp dst-port=444 

88   chain=forward action=drop protocol=udp dst-port=444 

89   chain=forward action=drop protocol=tcp dst-port=996-999 

90   chain=forward action=drop protocol=udp dst-port=996-999 

91   chain=forward action=drop protocol=tcp dst-port=3127 

92   chain=forward action=drop protocol=tcp dst-port=3129-3149 

93   chain=forward action=drop protocol=udp dst-port=3127-3149 

94   chain=forward action=drop protocol=tcp dst-port=445 

95   chain=forward action=drop protocol=udp dst-port=445 

96   chain=forward action=drop protocol=tcp dst-port=1434 

97   chain=forward action=drop protocol=udp dst-port=1434 

98   chain=forward action=drop protocol=tcp dst-port=113 

99   chain=forward action=drop protocol=udp dst-port=80 

100   ;;; conficker A/B
     chain=input action=drop protocol=tcp layer7-protocol=conficker A 
     dst-port=80 

101   chain=input action=drop protocol=tcp layer7-protocol=conficker B 
     dst-port=80 

102   ;;; conficker A/B

101   chain=input action=drop protocol=tcp layer7-protocol=conficker B 
     dst-port=80 

102   ;;; conficker A/B
     chain=forward action=drop protocol=tcp layer7-protocol=conficker A 
     dst-port=80 

103   chain=forward action=drop protocol=tcp layer7-protocol=conficker B 
     dst-port=80 

104   ;;; NetBEUI
     chain=forward action=drop protocol=tcp dst-port=445 

105   chain=forward action=drop protocol=udp dst-port=137-139 

106   chain=input action=drop protocol=udp layer7-protocol=conficker A 
     dst-port=137-139 

107   chain=input action=drop protocol=udp layer7-protocol=conficker B 
     dst-port=137-139 

108   ;;; conficker A/B
     chain=output action=drop protocol=tcp layer7-protocol=conficker A 
     dst-port=80 

109   chain=output action=drop protocol=tcp layer7-protocol=conficker B 
     dst-port=80 
-- [Q quit|D dump|up]

joegoldman · Mon Sep 22, 2014 1:53 am

Are the packets actually making it past your router and hitting the server?

In any case - a DDoS will continue to down any part of your network as far as it can go. You need to ask your upstream to ask their upstream etc to curb the attack all the way up to Tier1/2 level if needed (someone who has bandwidth to absorb it).

No matter how good your firewall is configured - if the traffic is hitting your router it will continue to flood your WAN links.

The other option is DDoS scrubbing providers such as Black Lotus and others, but these take some setting up and are not quick.

We recently underwent a 1gbit/s DDoS attack for nearly 2 weeks, and was helped by 3 levels above us co-operating and blackholing the attack.

CelticComms · Mon Sep 22, 2014 1:57 am

If you have already taken all the steps that you can at your end of the WAN connection then you may need your ISP / upstream to help. If you are already dropping the traffic as efficiently as possible and not doing anything which is assisting the attack then the attack needs to be dropped before it hits the limited bandwidth WAN link. A change of IP may help.

riccardo123 · Mon Sep 22, 2014 10:04 am

Thanks for your reply. ABout DNS amplification attack i know that i cant do much if it comes to my door. But what is happening now i am being ddos attacked on 1 of my webservers. It doesnt consumes trafic but i have thousand ip that open connection and they dont get replied.I have alot of connections which says unreplied and in my iis these stays as Time_wait. One thing i have noticed is that there are no multiple connections per ip. They are all different ip. I need some help to block these unreplied ip so they dont get to my server. We also changed the ip but as i see they attack our host which it doesnt matter if i change ip. I have tried syn flood protection with different limits but no help. And some times i block legitimate users. So some basic firewall rules which maybe can help block some of these connections.

Mon Sep 22, 2014 10:29 am

If you have changed IP it means IMHO that something is poisoned on the LAN side. How the attacker could know the new address ?
I have been experiencing same kind of attack. You need help from your ISPs and be patient. Drop or reject all DNS connections and wait....wait...wait
Do not forget to drop UDP and TCP port 53 from WAN side.

There was the disscussion what is better: to drop or to reject connections. There is no good solution.
I prefer rejecting with "no host" or "no net" as attacking machines could (sic!!!) be fooled that is worthless to send such packets and amplification
could be stoped.

riccardo123 · Mon Sep 22, 2014 10:44 am

Thanks for the answer. Problem is i am not worried about DNS amplfication attack.I am worried for the flood on my webserver.It makes it go unresponsive. usually we have max 400-500 users which navigate. But i am having 23000 connections on my webserver. All of them are unreplied beacuse they close the connection. How can i filter these addreses? Knowing the new ip is easy if myhost.com old ip 2.2.2.2 and if i change it just a simple ping can show my new ip.

kcybulski · Mon Sep 22, 2014 2:54 pm

Thanks for the answer. Problem is i am not worried about DNS amplfication attack.I am worried for the flood on my webserver.It makes it go unresponsive. usually we have max 400-500 users which navigate. But i am having 23000 connections on my webserver. All of them are unreplied beacuse they close the connection. How can i filter these addreses? Knowing the new ip is easy if myhost.com old ip 2.2.2.2 and if i change it just a simple ping can show my new ip.

Hi,

What is your SYN received timeout ? Can you lower it?

Best Regards
Krzysiek

CelticComms · Mon Sep 22, 2014 3:56 pm

If you detect the incomplete handshake and add the source address to an address list you can simply block those addresses for a time (days) so the future SYN attempts never get to the web server. Servers typically allocate resources when the connection starts so by blocking those requests the web server uses fewer resources. Whether this approach helps largely depends on how many zombies the DDOS network has.

Zorro · Tue Sep 23, 2014 5:01 am

from naives there was DNS and NTP amp attcks attempts aswell as syn-flood.
raw bruteforce may be nastier to deal with.
also there was several explioits in linux kernel itself, frequently exploited and relatively fixed in only latest kernles.

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