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Cracking the System - Scanning


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#1 Showstopper

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Posted 13 July 2009 - 03:47 PM

This is the next part of the guide which will cover scanning.

Cracking the System - Scanning:
by Showstopper


The next thing to do when trying to gain access to a system is scanning. Note that when scanning you are touching the system and scans can easily be picked up by an IDS. Scanning in short gives a layout of the targets network.

As stated scanning is detected but most administrators ignore or dont even know what they are looking at.

The most used scanning tool is nmap, but there are many.

TCP connection:
When you scan your target using TCP communication, there are six TCP flags can be utilized during packet transmission. A flag will indicate whether the sent packets are syn, fin, urg, psh, ack or rst packets.

Lets talk about the most common TCP Scan types. There are full scan, half open scan, stealth scan, and ack scan.

full: Completes 3 way TCP. Gives accurate results, but picked up easily.

half open: If the remote replies back to you after you have sent syn request, this means the port is open.

stealth: Scan ports randomly and reduces the speed.

There are many others these are just some main ones.

Next is UDP & ICMP Scanning UDP and ICMP connections most of the times are blocked at the firewall level.

UDP works by sending the packet and forgetting it. Say we came across a port and its open then that port on the system will not reply back because UDP doesnt give you the delivery packets during communication. Since there was no reply then it is probably open.

That is the basics of scanning. If you have any questions on anything let me know and I will do my best to help you.
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#2 Guest_Jordan_*

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Posted 13 July 2009 - 05:08 PM

Very informative, +rep! At CodeCall, if you scan the servers it will automatically ban your IP, forever. This means your TCP/UDP requests are dropped completely. Be careful who you scan if you care not to be blocked
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#3 Deathcry

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Posted 14 July 2009 - 11:06 AM

do you know a good tutorial that will discuss this topic in depth in c++.
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the code is with you

#4 Showstopper

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Posted 14 July 2009 - 12:04 PM

do you know a good tutorial that will discuss this topic in depth in c++.


Port scanning?
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#5 relapse

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Posted 14 July 2009 - 01:33 PM

So, once you've got all of the open ports, what next?
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#6 Showstopper

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Posted 14 July 2009 - 07:32 PM

So, once you've got all of the open ports, what next?


That is in the next tutorial which I have already submitted, just waiting for someone to accept it.
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#7 bbqroast

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Posted 21 July 2011 - 06:59 PM

Very informative, +rep! At CodeCall, if you scan the servers it will automatically ban your IP, forever. This means your TCP/UDP requests are dropped completely. Be careful who you scan if you care not to be blocked

Meh, turn off my router turn it back on. Ban FAILED
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Please, write clearly with proper structure. Double spacing makes the text feel un-jointed, Capitalizing Every Word Means People Stop Before Every Word Sub-Consciously Which Is A Pain In The Backside, and use code tags! (The right most styling box).




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