Posts Tagged ‘scanner’

This is just some quick script I hacked up to scan TCP ports using different source ports. The aim of the script is to find badly configured firewalls that allow traffic from certain source ports. This is for instance explained in the NMAP book. I’ve done it in scapy (yeah I know python ones again) and still admire scapy, it’s a wonderful piece of software. Here are some nice references if you decide to write your own networking stuff in scapy:

#   – http://www.secdev.org/projects/scapy/doc/usage.html
#   – http://www.secdev.org/conf/scapy_pacsec05.pdf
#   – https://cs.uwindsor.ca/~rfortier/CRIPT/uploads/slides/Python_Scapy.pdf

You can find the source here.

I chose manual output analysis, this means that the script doesn’t have any logic whatsoever and you will have to decide, if it allows or doesn’t allow traffic from different source ports yourself. Example output:

Received 34 packets, got 8 answers, remaining 28 packets
srcport, dstport, flags, humanflags
20,80,18,[‘SYN’, ‘ACK’]
20,443,18,[‘SYN’, ‘ACK’]
53,80,18,[‘SYN’, ‘ACK’]
53,443,18,[‘SYN’, ‘ACK’]
67,80,18,[‘SYN’, ‘ACK’]
67,443,18,[‘SYN’, ‘ACK’]
88,80,18,[‘SYN’, ‘ACK’]
88,443,18,[‘SYN’, ‘ACK’]

Hope it’s also useful for someone out there.

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Well it certainly is true, why not? That question never has a correct answer imo. It is the same question I asked myself yesterday. I was like thinking what to write on my blog (I was bored and thought that blog writing could help) after a while I just gave up (so lesson learned: only write when you actually have something to write). So today I fired up my browser(for the ones wondering, this is a personal opinion, I use: Opera {FTW!}, IE {nice}, FF {sucks}, I use them depending on what I need) and the first things I saw was this. Which is funny since it’s just a couple of days ago since I posted about python and now I see a nice and small python script to do funky stuff.

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