A Guide To OSI Model

Credits: prtablegm[HF]

This guide is not meant to be all encompassing. It is a reference to give someone who is interested in network security, but does not know where to start, some guidance of how to begin learning about the vast field of network security and where to look for information. The important thing to keep in mind is stay focused and learn little by little. It is easy to become intimidated when looking at the big picture and all that it entails. Focus on each section and gradually increase your knowledge base.



OSI Layers Explained

The Open Systems Interconnection model (OSI model) is a product of the Open Systems Interconnection effort at the International Organization for Standardization. It is a way of sub-dividing a communications system into smaller parts called layers. A layer is a collection of similar functions that provide services to the layer above it and receives services from the layer below it. (That part is a direct quote from Wikipedia for I could not say it better my self)

Physical Layer: The physical layer is at the bottom of this data networking model. It deals with crude data that is in the form of electrical signals. The data bits are sent as 0's and 1's. 0's correspond to low voltage signals and 1's correspond to high voltage signals. The mechanical aspects of communication, such as wires or connectors come under this layer. The physical layer also deals with how these wires, connectors, and voltage electrical signals work. Also, the process that is required for these physical aspects are taken into account in this layer itself. Read more on ethernet cable wiring.

The Data Link Layer: The transmission of the data over the communication medium is the responsibility of this layer. The 0's and 1's that are used in the communication are grouped into logical encapsulation. This encapsulation is called frames. The data is transported in frames. The responsibility of these frames is that of the data link layer.

Network Layer: All over the world, there are many different types of ethernets. These networks are connected to each other through various media. When a data packet wants to reach a particular destination, it has to traverse through these networks. Essentially, there are lot of operations that are taking place between the connected networks. Also, the packet data which is traversing, has to choose an optimum route, and the addressing of these packets has to be proper. The various operations between the networks, packet data issues, addressing and routing are handled by this network layer.

Transport Layer: The transport layer ensures quality and reliability of the communication. The data packet switching is entirely handled by the transport layer. There are basically two types of packet switching. They are connectionless packet switching and connection oriented packet switching. In connectionless packet switching, the packet data is allowed to choose the route in which it is going to reach the destination. Obviously, the packet in itself cant do this. Physical devices like routers are mainly responsible for the behavior of packets, but the packets formed from the same datum can reach their destination in different ways. Whereas, in connection oriented packet switching, once the route is decided, then all the packets have to follow the same route. Examples of connectionless packet switching are text messages in mobile phones, and the example of connection oriented switching is a direct voice call.

The Sessions Layer: The sessions layer is mainly responsible for creating, maintaining and destroying the communication link. PDU (Protocol Data Unit), in which various protocols are defined, that have to be followed during communication, are the responsibility of the sessions layer. The applications that use RPC's (remote procedure calls) are taken care of by the sessions layer.

Presentation Layer: There are various techniques of data compression which are used to send and receive the optimized data. For example, if certain data is repeating itself for a number of times, then it is logical to send the data only once, and specify the number of times it is repeated. This bundling of the repeated data is one of the techniques of compressions. The compression and decompression of the data is handled by the presentation layer. Also, encryption and decryption techniques used to thwart malicious attacks on data are handled by the presentation layer.

Application Layer: This is the topmost layer of the OSI reference model. This layer comes into picture when there is a process to process communication. Whenever a user invokes any application, all the associated processes are run. Many a times, when an application wants to communicate with another application, then there has to be communication between these associated processes. The application layer is responsible for this interprocess communication.

Thank you Keith Barker for this story.

Title:
King invites King to lunch.

Once upon a time, there were two Kings. King A and King B. They lived in separate kingdoms, kingdom A and kingdom B.

One day, King A, decided to invite King B to a lunch. No telephones were available, and King A doesn't have to ride a horse all the way over to kingdom B to personally invite King B, as both kings have a huge staff of 7 workers. So here is what happens for the invitation.

King A calls for staff member 7, the scribe (application layer), and the scribe writes down the message indicating that the local King A, wants to invite the remote King B to a lunch. The scribe puts this message into a container, such as an envelope. Staff member 7, the scribe, then hands it to the next staff member 6, the translator.

Staff member 6, the translator (presentation layer), simply ensures that the language that the scribe used, is appropriate for the language understood by King B?s staff on remote side. The translator puts the results in another envelope, and hands it to staff member 5, the negotiator.

Staff member 5, the negotiator (session layer), knows how to deal with people, and the rules for engagement for communicating with other kingdoms. He adds his 2 cents, and puts the results in yet another envelope. He hands this envelope to staff member 4, to the middle manager.

Staff member 4, the middle manager (transport layer) is very concerned about making sure that the envelope it received makes it all the way to kingdom B. In fact, if the envelope is quite large, the middle manager, staff member 4, may divide the envelope into 2, and label them 1 of 2, and 2 of 2 with the intent of getting an acknowledgment from the middle manager on the remote side (kingdom b), to verify that all the pieces got there. If the messages are not too important, the middle manager may just send the information, and not even ask for an acknowledgment. Depends on the rules for the specific message. Either way, the middle manager, hands the envelope(s) down to staff member 3, which is Google maps guy, who only has the ability to the world from a 5,000 foot view, and no closer.

Staff member 3, looking at the view of the countryside from 5,000 feet (network layer), and seeing that the envelope is to be delivered to kingdom b, sees that kingdom b is absolutely remote, (not local), and adds information regarding whether the message needs to travel North, South, East or West. In this example, lets say that staff member 3 made the decision that the message needs to go east. After adding that, he hands the envelope to staff member 2, which is the mail room guy.

Staff member 2, the mail room guy (data link layer), knowing that the message needs to go east, takes a look at all of his carriers, (FedEx, UPS, USPS, Carrier Pigeon, etc), and if there is only 1 that is going east, he prepares the message for that carrier. It if is FedEx, staff member 2 puts the message in the appropriate FedEx envelope (frame), and puts it in the pile for FedEx pickup.

FedEx isn't really a staff member, but if they were, they would be staff member 1 (physical layer), who takes the data and causes it to actually leave kingdom A, on its way (finally) to kingdom B.

Now, let's go on a road trip, and see what happens in Kingdom B, when the message arrives there.

The package, finally arrives at kingdom b, and is received at kingdom B's mail room and follows this process:

Mail room receives L1 via FedEx, or possibly another carrier that FedEx handed off to in transit.

Mail room (L2)verifies that the package is for us, at this castle based on the house (castle) number, and hands it to google maps guy at L3.

Google maps guy (L3), looks at the map and says, yup, this envelope doesn't need to be forwarded to any remote location, as it is destined to us. I will just remove the google map info, and hand it up to L4. (Note, if the message needed to go to a different street , the google maps guy would add new information, such as north, south, east or west, and push it back down to the mail room to be sent.)

Middle manager, (L4) is nervous, as the envelope says 1 of 2, and he wants to keep his job. He puts a sticky note on his monitor, that says look for envelope labeled 2 of 2, and if that second envelope doesn't arrive, he may take the initiative to send a little message back to the middle manager at kingdom A, asking for a resend of that information. As data does arrive, middle manager removes any information applied by the remote middle manager, (such as information regarding 1 of 2, and 2 of 2), and pushed the info up to L5.

The negotiator, (L5), understanding the politics and rules for engagement, accepts the contents of the envelope, using any special rules that the negotiator on the remote side may have imposed or recommended. Removing any L5 specific information, he pushes the rest of the data to L6.

The translator (L6) sees that the sender used English, and our local kingdom understands English. He also noticed that there was some short hand used by L6 on the remote side, so the local side decompresses that, and hands the results up to L7.

The scribe (L7) takes the message, approaches King B, and reads? King A, invites you to lunch!?

All that for a lunch invitation!

Any ideas on what process happens if King B responds?

Same logic on virtually all media types.



Ways to remember the OSI Model

Please Do Not Trouble Steve's Pet Alligator
Please Do Not Throw Sausage Pizza Away
All People Seem To Need Dominos Pizza
American Pu**y Seems To Need Deeper Penetration
All People Seem To Need Data Processing
All Prostitutes Seem To Need Double Penetration

Yes it just keeps going. Whatever it takes to remember the OSI model.
Enjoy...

Unlock Memory Card Password (NEW)

As You know,
There is almost no way yet known to hack the memory card password in case of these types of phone but there is a way to do it some of the Nokia s60 3rd edition phones and almost all the E-series phones.
The remote lock option in E-Series phone allws you to unlock your phone by sending a sms.
The only thing you have to do is to activate this feature by going to Tools | Settings | Security | Phone and SIM | Allow remote lock menu. The password of your memory card will be your remote lock message.
So you have to just send a sms containing your remote lock message that will automatically change your memory card password.

Enjoy...

Difference Between FTP and Shells

Difference between FTP & Shells:

Many times I see that some of us know how to use the shell but once they have uploaded they get confused. So to start with, Let me give you some information about FTP:

File Transfer Protocol

Whenever you want to open your website, the first thing you will do is to get some web hosting for your self. That cud be either free or paid. When your get your hosting services, you create a website on your computer first and then upload it to your hosting server so it becomes a World Wide Web. This process of uploading the documents from your computer to your hosting server is done through FTP [File Transfer Protocol]. It basically looks like a program with 2 columns, one column shows your computer files and another shows your servers files. Just like when you copy the stuffs from some USB drive to your computer. So here, I will show you an example is how you would connect if you own go4expert. So when you want to connect your self to your web hosting server, following information is required in order to authenticate yourself:

Server : ftp.hosting.com
Username: ankit_world
password: whatever

So, once you put in this information, server understands that you are shabbir and gives you access to all the files on the server so you can work on it.

Shells:

Since you understand the FTP now, we know that none of us will get access to Go4expert's server because we don't have the username and password authenticate yourself. Somehow we can manage to get the access to G4E's FTP we can easily remove/edit/replace files. So we can destroy this entire forum and upload our own stuffs. That is when shells comes into the picture. Shells are a malicious PHP files which you will need to upload to any website, and once you execute it you will get access to its server directly WITHOUT authenticating your self.

Moral of the Story:

I wrote the difference between FTP and shells so that you guyz can understand it, because lots of people tends to get confused between them. So again to make it clear, you can following thing:

Quote:

FTP is a protocol that lets you connect your computer to your hosting server so that you can upload/edit/delete/replace your files. Since we wouldn't have the username & password to connect to any website's ftp, thats why we will use the SHELL to get access. SO SHELL IS NOT FTP BUT IT GIVES YOU ACCESS TO THE HOSTING SERVER.

Funny Incidents:

Let me tell you guyz why i gave time to write this much about FTP in this article. In my forum, i reelased a couple of videos about "hacking with shells" etc .etc. So some guyz saw it and just copied what I was doing without understanding the logic.

I remember i saw couple of threads which said following thing:
" Hi guyz, i managed to hack my 1st website today! YAY, I am really happy! But theres only 1 problem, i uploaded the shell and ran it and it worked fine. The only problem is i dont have access to FTP."

Y0, i hacked a website today, uploaded a shell and it worked fine, now i am trying to get access to FTP 
 

Enjoy...

Become SYSTEM User in Windows Xp

If you think Administrator has the largest privileges onto the computer, then you're wrong. there is a user who is named SYSTEM.

System has full control of the operating process and it’s kernel. in case you open windows task manager (press ctrl+alt and delete) you will notice that SYSTEM User controls several processes. These processes can't be closed by Administrator.

In this tutorial they will see how to trick Windows into jogging our desktop as process. So we’ll obtain a much greater privileges over computer.

1.Open Command Prompt. Go to Start , then Run. In Run option type cmd and click OK. After this will openCommand Prompt, or Start->All Programs ->Accessories->Command Prompt
 

2. In Command Prompt write at 13:55 /interactive “cmd.exe” and press enter , the time is usually a minute or five ahead of your present time in the 24 hours format.

After a minute or five will appear new Comand Prompt Window wit different title bar. it's changed from cmd.exe to svchost.exe.
 
3. End current explorer.exe method. Open Task Manager, select explorer.exe and click End method.
 
4. In new Comand Prompt with title svchost.exe write cd.. and press enter , then write explorer.exe and press enter.

After this you will become process user,

Enjoy...

The Ultimate Guide to PC Security

Being a hacker, you're coming face to face with some of the most malicious programs on the internet every day. You want to be secure. Most of the programs you'll be downloading will be malicious, so how can you tell if the program will be working against you or for you?
This guide will be looking at the scanning of malicious files, as well as a guide to anti-viruses & firewalls and a brief introduction to sandboxing and anonymity. So yep, you're in for quite a bit of reading. Grab a drink, maybe a cigarette.
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Being secure is important. Just because you call yourself a hacker, it doesn't mean you're immune to attacks towards your computer. Without my anti-virus, I doubt I'd actually be typing this now - I'd probably be searching through my registries and screaming like a chicken on speed. I'm like that.
Not all anti-viruses work the same way. Some anti-virus programs are bad; some are good, and some are just plain useless. We'll be looking at which ones are the best of the best, and which ones are just plain fail.
Being infected with something can also put your friends and family at risk, other users of your computer could be having their login & credit card details stolen without any knowledge of it. Worms can also spread to your email contacts and friends on popular websites such as Facebook.


Downloads & Scanning
For example, you download a program and the poster is claiming that it is a clean botnet controller. If we can this, it will come up with results such as "Win32/RBot" etc.. This means that the file should be what we wanted.
Now, if the botnet-controller scan came up as something like "Win32/trojan.agent.a", we can tell that this is a malicious program that will work against us. This is an example of a download you do not want to use.
All in all, the scan should show results similar to what you were downloading.
You should always be careful what you download. You may often be downloading malicious software without even realizing sometimes. Trust me, this happens to a lot more people
Web-scanners such as "VirusTotal" and "NoVirusThanks" are becoming increasingly popular with the amount of anonymous downloads posted all over the internet.
If you want to scan a file you find suspicious, you can go to either http://virustotal.com or http://novirusthanks.org to do so.
VirusTotal will send samples of the file to the antivirus companies, so this is not recommended if you want to keep your file undetectable.
NoVirusThanks has an "Advanced options" area where you can choose to not distribute your file to the antivirus companies, this is handy for keeping things fully undetectable, but if it's a file you don't trust and don't want yourself or others to be infected by it in the future, I suggest you allow them to distribute it to the antivirus companies. I respect what these websites and the malware fighting websites do, and so should you.


When opening emails, you should also be cautious. Just because it's an email from your friend - it doesn't mean you can trust it! You may see some emails asking you to update your bank details -- your banks should never ask you to do that via email. The details you enter will be sent out to someone who is going to exploit your details, so steer away from these emails.
Worms can be spread via email. For example, you open an email from Bob containing a worm, this worm is then sent to all of your contacts. This is how most worms will work, and it is suggested that you change your emailing service if it could be vulnerable. You can use Microsoft's live hotmail service which is excellent, it will also disable any harmful content from downloading onto your computer. You can find this service at http://mail.live.com
Sandboxing
By using a sandbox, everything that is downloaded onto your computer will remain in the sandbox. It will not escape, meaning that malicious downloads cannot harm your computer. Sandboxing is a great way to test whether or not a website can be trusted. I rarely do this, but it's so useful sometimes.
Sandboxing will also protect your cookies, history and cached temporary files from being leaked. Downloads are isolated, meaning that they are trapped and your computer is protected.
Here is a download I posted for Sandboxie v3.32

http://www.4shared.com/file/71942764/d1b6ca41/Sandboxiev332.html?s=1
The main use of a firewall is to prevent incoming traffic, which will stop things like 'telnet' from reaching your connection, and can also stop worms etc. from accessing your network. Firewalls will also block the backdoors that trojans create, so if you find yourself unlucky enough to have a RAT (Remote Access Trojan) on your computer, the backdoor should be blocked by your firewall, Having a firewall does not mean you are secure, many firewalls can be easily disabled or bypassed by malware. Do not think you're secure just because you have a firewall, this is a common misconception with firewalls. Too many people think that by installing a highly popular firewall, they'll instantly be secure against the latest intrusions, but this is not at all true.
you may notice a difference when you get a firewall, but the download speed may remain normal on users with slower speeds. This effect can vary between users, and depends on the connection. It's best to try several firewalls to find out which one suits you best - reviews are personal and will not always be the same for everyone.
One of the favourite firewalls is "ZoneAlarm" which is very popular and has a free version. The paid version is obviously better, but it isn't necessary at all.
If you're using Windows Vista, I'd recommend choosing ZoneAlarm as your firewall. The same goes for XP, but you might want to get your hands on a "BlackIce" crack instead, if possible.
Another great Firewall is "Comodo" which is also free can be found here...
Comodo: http://www.personalfirewall.comodo.com/
Z

one Alarm: http://www.zonealarm.com/store/content/c...wall_b.jsp
Ghost: http://www.ghostsecurity.com/ghostwall/
Essential Additions.
There's a few more tools which I'm sure you'll definetely want to get.
HijackThis is a tool used to scan the areas of your computer which viruses are often located in. It will also scan the registry areas which hold the legitimate programs and, quite often, the infections. It is best not to delete ('fix checked') any entries on HijackThis unless you know what you're doing, as you may be removing something which is a required part of your system.
Another good thing about HijackThis is the fact that it's so lightweight, it uses barely any memory, it's easy to use, and you don't need to keep it running!
This is a great area to check if a process is harmful or not: http://www.bleepingcomputer.com/startups/
HijackThis can be found here: http://www.trendsecure.com/portal/en-US/...hijackthis

thankss...