I have installed Snort and it does not detect majority of attacks, such as nmap port scans, downloading exe files, opening documents containing keyword "root".

I use Snort together with Pulled Pork and Barnyard2. Everything seems to function and I can see alerts on the website that is powered by BASE.

The problem is that I can only trigger 3 different alerts. Everything else is simply not detected. I want obviously to be able to get alerts when someone performs port scanning, trying to attempt to perform DDOS attack and so on. This I cannot trigger. Do I have to enable something somewhere?...

I have made my own local.rules file, which contains a single rule - monitoring of ICMP echo packets.

Pulled Pork does show that it has downloaded over 20000 rules and over 5000 rules are enabled. This can be seen in snort.rules file, which I included in snort.conf file.

The 3 alerts I am able to trigger are:

  • stream5: TCP Small Segment Threshold Exceeded (this is due to my old Win SCP client)
  • ssh: Protocol mismatch (this is due to my old Putty client)
  • ICMP test (my own rule from local.rules)

My snort.conf can be found on the following website (had to move it there, because i reached max chars list): https://paste.ee/p/RTUgY

My pulledpork.conf can be found on the following website: https://paste.ee/p/ixZqW

My local.rules looks like this (which does work):

alert icmp any any -> $HOME_NET any (msg:"ICMP test"; sid:10000001; rev:001;)

1 Answer 1


Ok Break your Question with its solution into parts.

  1. PortScan

    There are some configurations that you need to change to enable nmap portscan open the snort configuration file with sudo gedit /etc/snort/snort.conf.

    uncomment and modify this line ( #428 usually ) :

    Portscan detection. For more information, see README.sfportscan

    preprocessor sfportscan: proto { all } memcap { 10000000 } sense_level { medium } logfile { /var/log/snort/portscan.log }

    sudo service snort restart

  2. Downloading exe file

    You need to find rules or write your own rule.It mostly present in ET or Snort rules by default you need to find it and uncomment it.

You can find each type of rule for the purpose you are requiring there /etc/snort/rules/snort.rules (In most cases) You need to find your own file.

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