Sometimes you do not need a detailed log-analysis but several simple one-liners that you can adjust without too much thinking how it works, what you did last time, etc. The examples below are absolutely NOT optimal, but rather modular for easy line-editing.
1. Allowed traffic:
cat asa.log | grep permitted | grep access-list |
sed -e 's/^.*permitted//' -e 's/hit-cnt.*$//' |
sed -e 's/([0-9][0-9]*) ->/ ->/' | less
Result:
tcp outside/10.2.8.30 -> inside/10.1.141.23(8080)
tcp outside/10.2.8.30 -> inside/10.1.141.23(8080)
tcp outside/10.2.8.35 -> inside/10.1.140.137(13000)
udp outside/10.2.8.25 -> inside/10.1.9.14(137)
udp outside/10.2.8.25 -> inside/10.1.81.15(137)
tcp outside/10.2.8.44 -> inside/10.1.140.137(13000)
tcp outside/10.2.8.31 -> inside/10.1.140.149(13000)
Noticed the “permitted” strings?
2. Denied traffic:
cat asa.log | grep denied | grep access-list |
sed -e 's/^.*denied//' -e 's/hit-cnt.*$//' |
sed -e 's/([0-9][0-9]*) ->/ ->/' | less
Result:
tcp inside/10.1.140.159 -> outside/10.2.8.24(515)
tcp inside/10.1.140.159 -> outside/10.2.8.24(515)
tcp inside/10.3.241.116 -> outside/10.2.8.251(1541)
tcp inside/10.3.241.116 -> outside/10.2.8.251(1547)
tcp inside/10.1.140.159 -> outside/10.2.8.24(515)
3. The most popular permitted traffic:
cat asa.log | grep permitted | grep access-list |
sed -e 's/^.*permitted//' -e 's/hit-cnt.*$//' |
sed -e 's/([0-9][0-9]*) ->/ ->/' |
awk ' {conn[$0]++;} END { for ( i in conn ) print conn[i]," ",i;}' | sort +0nr | less
Result (the first column is the amount of corresponding log entries):
21170 tcp outside/10.2.8.40 -> inside/10.1.140.149(13000)
18023 tcp outside/10.2.8.34 -> inside/10.1.140.149(13000)
17981 tcp outside/10.2.8.31 -> inside/10.1.140.149(13000)
11034 tcp inside/10.1.140.251 -> outside/10.2.8.68(10001)
10652 tcp outside/10.2.8.43 -> inside/10.1.140.137(13000)
10628 tcp outside/10.2.8.44 -> inside/10.1.140.137(13000)
10484 tcp outside/10.2.8.47 -> inside/10.1.140.137(13000)
10437 tcp outside/10.2.8.23 -> inside/10.1.140.137(13000)
7618 tcp outside/10.2.8.25 -> inside/10.1.140.137(13000)
7550 tcp outside/10.2.8.27 -> inside/10.1.140.137(13000)
7515 tcp outside/10.2.8.49 -> inside/10.1.140.137(13000)
7496 tcp outside/10.2.8.29 -> inside/10.1.140.137(13000)
6826 tcp outside/10.2.8.30 -> inside/10.1.141.23(8080)
6011 tcp outside/10.2.8.35 -> inside/10.1.140.137(13000)
5896 tcp outside/10.2.8.40 -> inside/10.1.141.23(8080)
5809 tcp outside/10.2.8.30 -> inside/10.1.140.137(13000)
4. Modification for versions 8.2+:
cat asa.log | grep Deny | grep access-group | sed -e 's/^.*Deny//' -e 's/by.*$//' | sed -e 's/dst/ ->/' -e 's/src//' | less
You can use this method to generate a policy based on the current traffic.
Additional “greps” will allow you to filter for specific ports or IP-addresses.
Replace “permitted” with “denied” and you’ll get the “most popular denied traffic”.
