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    The "Dupe"

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    Youngcha
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    The "Dupe"

    Post by Youngcha on 09.09.11 15:13

    Well, as i'm sure all of you know there's been a duping outbreak. What i'm sure almost non of you know, is I actually run my own 2d game and was curious about it to stop it from happening to my game. I contacted a accused duper here, and asked him about it, explained who i am, what I do, my intentions etc. I told him several times "I don't care if you do or don't dupe, that's not really my concern and I'd prefer not to actually know. But, you do strike me as the type of guy who knows about it" He came right out and said he duped and wasn't fond of giving out how to do it. I started asking him about the software for it, if he has any idea what it's functions are, the idea and logic behind it, and he told me there was no software. Basically what I've got from it will be posted below, I will not be putting how to type.. he told me now I rather he didn't.

    As I explained to Hayley and Hantz, everything you do on the net is in packets. A packet has separate parts that act like a literal piece of physical mail.

    First, you have your sender and destination IP's which act as your Names in the letter, exactly the same.
    Second, you have your sender and destination MAC's which act as your Addresses in the letter, exactly the same.
    Third, you have the data, the composed letter which gives packet info such as RNG data (Drop rates, Crit, etc) the next is FTP (Messages, Damage encoders which are also set in an RNG range, etc)
    The last bit, is know as the CRC and PAD.
    The CRC is key in my line of work, which is packet manipulation. Basically, if you've ever sent a text in a no service area and after 20 seconds it says can not be sent and drops the text, that's a CRC.
    The CRC pings the server basically saying "Hello, I has a message for you, this is the type of file, will you accept it?" it continuously sends this to the server until it accepts, kind of like your kids screaming "Mommy, Mommy, Mommy, Mommy, Mommy, Mommy!" The CRC has a max life time of 20.17 seconds. It can be as short as 18.34 seconds.
    The PAD is basically a data filler, I've never really messed with it but it has bitten me in the ass. Basically, the PAD is what makes you send x2 texts when you only sent one. After a certain data rate, it starts a new packet to send. If you say for instance have my phone which is a max of 160 letters and you only send 54, the PAD will inject 0's after the ASCII to fill the data rate. That's about it.

    Now, you understand packets. I first thought that it was use of software that basically clipped the CRC and made an x2 packet creating two items. Basically the packet sends twice, and since you cut the CRC and the server already accepted the packet, you can force a new one in. However, it's not that at all. I won't explain the process, but basically due to logging out it can force a roll back to prior to say an exchange which drops the packet and goes through with the exchange, but also creates another because the server never fully got it all.

    The fix, i'm currently working on a fix for my game testing a similar process that is not working... (Go go better coding of drops.ini) What I plan on doing is making a check that cross references item ID's and their custom stats to make sure within a certain percential they are not the same. Of course to do this perfectly without deleting anything, I will have to extend the item ID's from say 462 which in my game is a weapon called "The Force" to say 462-1 for the first weapon, say if I dupe 462-1 and it is found to be a dupe, the code will then change to 462-1x

    I plan to send Nexon the code and system when it's finished, but knowing them they won't go through the work of adding it. I do however believe that it is beneficial for everyone to understand what is going on and how beneficial things work rather than sitting in the dark, this is why i'm posting this when it has no bearing on really anyone in the guild.
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    thetavi
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    Re: The "Dupe"

    Post by thetavi on 09.09.11 15:23

    Awesome, that's really interesting. I already kinda knew how the dupers were doing it, didn't know the whole packets thing though. Am I arrogant for saying it really doesn't sound all that complicated? o.O
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    Youngcha
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    Re: The "Dupe"

    Post by Youngcha on 09.09.11 15:50

    Nope, I have this gift to simplify things with using unlogical advances? It somehow makes sense to people, kind of why I want to become a professor. I used to teach at a high school, they didn't understand packets so I explained it that way. They were in the top 1% in the nation on their NOCTII's for packets, top 5% for overall scores. Every single student.
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    Carlos
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    Re: The "Dupe"

    Post by Carlos on 09.09.11 16:05

    Maplestory was designed to be hacked/exploited. It's just a matter of who chooses to hack/exploit and who doesn't and that's what separates the players. From my understanding, manual duping is when you send the server a packet that doesn't make any sense and it crashes the channel. Example, the cake vs pie dupe where you'd send a packet to be on the other team's side while the NPC gave teamed you up to the other side. Boom, crash. Another one was the Newbie character gift. Record the packet to receive the cash item on a new character, send it on an old character; boom, crash. I've seen so many people do this stuff. There were other methods but I don't really know what they are. There is a current method that I was told of that was tested and worked in Windia recently. I don't know if any of this information will help you but if you need information on any other dupe methods I'll see what I can dig up.
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    Youngcha
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    Re: The "Dupe"

    Post by Youngcha on 09.09.11 17:53

    Carlos wrote:Maplestory was designed to be hacked/exploited. It's just a matter of who chooses to hack/exploit and who doesn't and that's what separates the players. From my understanding, manual duping is when you send the server a packet that doesn't make any sense and it crashes the channel. Example, the cake vs pie dupe where you'd send a packet to be on the other team's side while the NPC gave teamed you up to the other side. Boom, crash. Another one was the Newbie character gift. Record the packet to receive the cash item on a new character, send it on an old character; boom, crash. I've seen so many people do this stuff. There were other methods but I don't really know what they are. There is a current method that I was told of that was tested and worked in Windia recently. I don't know if any of this information will help you but if you need information on any other dupe methods I'll see what I can dig up.

    You're right, games like this are made to be exploited. I'm not looking up how to fix it, just how to track and prevent it. Basically, my system sends a search for x packet's, when it finds it, it tracks it back to where it doesn't make sense, there it logs and reports the info to be determined by a gm (Me) that way you can find out who's duping then put in a patch to prevent the current dupe.
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    Luis
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    Re: The "Dupe"

    Post by Luis on 10.09.11 0:51

    =( so... much... to read T_T

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