configuring rules

[Sharif Uddin <Sharif.Uddin () spectrumasa com>]

Hello


I needs some help in writing some rules to test my network.


I have set up snort, barnyard2, snorby on centos 7


My home network is

ipvar HOME_NET 
[172.16.0.0/22,172.16.12.0/24,172.16.13.0/24,31.221.13.192/29,62.49.167.0/29,62.49.167.8/29,192.168.254.0/24,192.168.202.0/24,192.168.218.0/24,10.0.2.0/24,10.0.3.0/24,192.168.15.0/24,172.16.64.0/18,172.16.15.0/24,172.16.16.0/22,10.0.0.0/24,10.0.1.0/24,192.168.252.0/24,172.16.171.0/24,10.40.135.0/24,172.16.8.0/24,172.16.9.0/24,192.168.0.0/24,172.0.0.0/24,105.0.0.0/24,192.168.1.1/24,192.168.224.0/20,212.103.166.96/30]



The following are some test rules which I put in local.rules


alert icmp !$HOME_NET any <> $HOME_NET any (msg:"ICMP"; sid: 1000001; rev:1;) # external ping to internal network?
alert tcp $HOME_NET any <> $HOME_NET any (content:"|00 01 86 a5|"; msg:"mountd access";sid:1000002;rev:1;)  # found a 
sample online which has not responded to anything
alert tcp !$HOME_NET :139 <> $HOME_NET any (msg:"NetBIOS Session";sid:1000003;rev:1;) # test external ip trying to mount
alert tcp !$HOME_NET :445 <> $HOME_NET any (msg:"SMB over TCP";sid:1000004;rev:1;) # test external ip trying to mount


Have I written them correctly?


For my samba alerts I have found it also includes internal network, when I look at the source port on snorby, its not 
always 139 or 445. What am I doing wrong?



Sharif



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