[Snort-sigs] I need a rule for synk4.c attack
WirthJe at ...511...
Wed Apr 10 08:51:08 EDT 2002
> How can I write a snort (snort 1.8.6) rule for the synk4.c syn flood
> (with spoofed IP) attack program ?
> Here is the tcpdump of the attack:(destination port 80 supplied as an
> cat TCP\:1368-80
> 04/09-17:05:43.860348 10.10.10.10:1368 -> 10.15.0.27:80
> TCP TTL:30 TOS:0x0 ID:29579 IpLen:20 DgmLen:40
> 1*****S* Seq: 0x28376839 Ack: 0x0 Win: 0xFFFF TcpLen: 20
Flags set = S (SYN) and 1 (Reserve bit)
> I have tried the above rule to detect the attack, but It doesn't
> recognize it (I have changed the sequence number of the original rule)
> alert tcp $HOME_NET any <> $EXTERNAL_NET any (msg:"DDOS shaft
> flags: S; seq: 674719801; reference:arachnids,253;
> classtype:attempted-dos; sid:241; rev:2;)
Shouldn't the flags option be: "flags: 1S"
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