Reverse Engineering for Noobs Step by Step guide to crack A One Video to Audio convertor

Its been some time since I have written a reverse engineering tutorial, & I thought it would be good to cover one at the dead of night :) What I am going to teach you today, is a simple reverse engineering tutorial.We will be cracking A-one Video to Audio convertor today, with just simple cracking. You can also give a read to a step by step guide to crack Winrar to have an insight into reverse engineering & decompiling, however this one is completely different & requires little to no programming & ASM knowledge.

 

Disclaimer – By Reading this tutorial You agree that this tutorial is intended for educational purposes only and the author can not be held liable for any kind of damages done whatsoever to your machine, or damages caused by some other,creative application of this tutorial.

In any case you disagree with the above statement,stop here.

Requirements

• A-one Video to Audio convertor (Download from yaomingsoft.com)
• OllyDBG
• Time & Patience

Download & install A-one Video to Audio convertor. Now as you can see, its a trial version & once you try to register it, it gives an error <obviously>, & we need to find ways against it.

Now, to being with, fire up OllyDBG & load the A-one Video to Audio convertor EXE file in it.

Now, right click on

CPU window -> Search for -> All Referenced Text Strings

& in Text string window, right click -> paste the "Registration code is error" string (which pops when you input wrong serial) After you find it, double click it & navigate to the memory address.

Now, once you have reached the intended memory address, you can navigate a bit up to see the "register successful" string.

Navigating a bit above will get a simple logic which calls a specific function, & then the function returns a result which is compared to EAX

CMP EAX,1

& then jumps to 407A0F

JNZ SHORT 00407A0F

which is the "register failed" condition.

The whole scenario means that if value of EAX is anything less than or grater than one, the program will be a trial version & will not accept any invalid serial key.

Now, you can put a break point above the function call by pressing F2 & run the program, & enter the serial, the program will break & we can then navigate inside the function by pressing F7

You will get into function code. Add the breakpoint there by pressing F2 & restart the program again by pressing Ctrl + F9

Run it again & you will find that it will break it at 00406B40 (where you put the last breakpoint)

now, we will execute code step by step by pressing F8, once we go a bit down, we find

JNZ Video2Au.00406C4A

which jumps below to

POP EDI

& further we find that the value of EAX is XORed to 0.

so in order to insert a precise value into EAX, we will modify by double clicking

XOR EAX,EAX

& changing it to

MOV AL,1

which will set the accumulators value to 1 because

EAX        -    32 Bit reg <extended>
AX         -    16 Bit reg pair
AH / AL    -     8 Bit regs

where AL will represent the lower value, & setting it to one will set the accumulator to a precise value of 1, hence setting value of EAX to 1,which will lead to program being registered :)

now once you have done it, right click the code,

copy to executable-> selection.

In the coming window, right click again, save the file & you have a cracked working version of the software, paste it in program files directory & insert any serial.

it will work :D

 

I hope you liked it :)

like this post ? you can buy me a beer :)

Posted by XERO. ALL RIGHTS RESERVED.Source

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Romania and the Last Frontier Day 8 and 9 A Grand Finale

I have decided it it time to finally wrap up this trip to Romania in one extended blog post. All the photographs that follow are from day 8 of the trip as the ninth day was fully taken with travelling back home.

Another very early start saw myself and Rene heading back to the Northern Jackal hide for our last attempt on these enigmatic animals. Overcast conditions prevailed above once more but at least is was a white cloud rather than deep grey which increased the availability of light. The carp carcasses were staked out and once again within a short time a jackal head nervously appeared out of the longer grass and scrub area to the left of the hide. We had three jackals appear that morning which seemed to be a an adult male, a female and a sub-adult. These jackals are quite nervous animals and the large male seemed fairly possessive over the carp breakfast. I guess in total we had the jackals in front of us on and off for seemed to be around 20 - 30 minutes in total allowing plenty of time to get some more photos to add to those taken in the preceding days.

The jackals sloped back off into the scrub. Again the action was over relatively quickly and so we still had plenty of the morning session available. Once we were certain the jackals had completely left the area we called Luca who came and collected us. We had decided we would spend the rest of the morning in a reed clad  hide located closer to the hotel which overlooked a small reed lined pond with a scattering of lilies across its surface. The main target birds for this pond were Kingfisher and Pygmy Cormorant.

We were not sat there very long before we heard the distinctive high pitch call of the Kingfisher and a male bird came speeding in towards the hide and landed on a perch in the water in front of us.
The bird departed and flew across to a post in the middle of the pond where it dived a couple of time before returning in front of us and disappearing once more.

Whilst waiting for it to hopefully reappear there were some other birds in front of us. A Squacco Heron stalking through the reedbeds on the far bank and a pair of Ferruginous Duck. I concentrated my efforts on the ducks having taken so many heron photos in the previous days. The drake was preening and as with virtually all birds this was followed by the obligatory wing flap to shake down the feathers.

Another shrill call announced the return of the Kingfisher, a female this time.
At this point Rene and I part ways with him deciding to stay in the hide to see what else may arrive whilst I decided to walk about 20m away to where a pop-up hide had been placed next to a sandy depression in the bank for European Bee-eater. If you look carefully in the photograph below you can just see one of the birds perched in the tree behind.
Just for your interest, this was the camera few from the hide. Always a pleasure to have these colourful birds in the camera viewfinder.
There were no nest holes in the bank and at first it did not look very promising but there were plenty of birds gliding around nearby and it was not long before I had a pair perched up in front of me. Having taken a few portrait photographs of these technicolour birds that look like they have flown through a wet rainbow, I spent a little time trying for a couple of landing photographs. The birds were just beginning a nest excavation in the bank as you can see by the small depression in front of this bird.
The birds were being fairly un-cooperative for the landing photos but this partly resulted from the perch being too long giving them to much choice of where to alight.
The sun was getting high now, the light harsh and the air becoming wobbly with the rapid rising temperature outside the hide, so I decided to bring the morning session to an end and head back to the hotel for a coffee.

Over another tasty lunch we all sat down and discussed our plans for the final afternoon / evening session. Rene, Paul and Kevin decided they would go off site with Luca and Zoltan with a drive of around 40 minutes to an area with Collared Pratincole. I decided I would stay and take out one of the electric buggies and see what I could find to photograph around Ultima Frontiera.

Mid-afternoon accompanied by the whir of an electric motor I headed down to the south end of the site to start my afternoon in a hide for that had been set up for Marsh Harrier.

My transport for the afternoon

The hide was a strange one! A tiny box raised up on long supports overlooking a vast area of reeds with an old tree branch a short distance in front. This was not a hide for the claustrophobic as it was so small I had to leave my bag outside at the foot of the entry ladder. Once settle in it was obvious flight photos were going to be nearly difficult as the slight breeze was not in an ideal direction and there was a fair amount of heat and water vapour haze rising up off the reeds. I had seen a couple of harriers at distance and continued to wait cramped into the box. A male bird suddenly appeared from nowhere and settled on the perch.

This was the first time I had seen a Marsh Harrier that was not in flight and they are such an attractive bird of prey.

The male stayed a short while  but did not really do much beyond the above photo except rearrange a couple of feathers before taking flight once more. I decided under the conditions I was not really going to get much more out of the hide and had a growing need to stretch my legs. Under some better conditions the potential for this hide to provide some amazing harrier photographs would be very good.

What to try next? I remembered there was a hide nearer the hotel set amongst a series of old square fish ponds where the previous day Luca had managed a nice photograph of a Purple Heron and Rene and Paul had seen some Musk Rat. I convinced myself it was worth checking. This hide was not ideal sited as it was set up quite high on the bank and therefore not providing the ideal viewpoint of anything in front of it. It was very quiet except for a family of Mute swans including a very aggressive male. My hopes were raised when an adult purple heron flew in behind some reeds to the left but this was soon flushed by a herd of free ranging cattle. After staying in the hide a while I decided my efforts would be better directed elsewhere and remembered the Penduline Tit nest that was just around the corner that Zoltan had showed me the previous day.

Getting photographs of this tiny masked bird was a trial of patience as it zipped around between nest, low bushes and reeds but eventually I managed to get some photographs I was happy with.
The evening was starting to draw in now so I decided I would go off on one big final circuit and just see what I could find along the way.

The first photo opportunity was with a beautifully coloured Red-backed Shrike which was glowing in the late sun. The bird was quite difficult to photograph as it was one of those that just wanted to stay a little too distant in front of me, as it flipped between low bushes, and as I tried to creep up on it in the electric buggy. Eventually it paused on top of a bush for a moment allowing me to get close and a couple of shots. Such a shame these birds have been lost from the UK.
Moving along one of the southern tracks, a European Roller was perched in a low tree. I expected it to peel away in flight and a blur of blue as I approached but it just sat there in apparent curiosity. I really like these birds, which are about the size of a jackdaw, but they do spend long periods sitting around doing not very much.
After a while the curiosity seemed to get the better of the bird and it flew down to a bush right next to me. By this time I was standing at the back of the buggy which I was trying to use as some cover. Such a pleasure to be so close to one of these birds. It just sat there cocking its head to the sides and inspecting me before another flew by which it joined.

I was heading back to the hotel now as the light was dropping fast. On the final approach a Hoopoe  made me stop briefly and I got a nice full sequence of photographs as it dispatched another mole cricket excavated from the sandy track below. These were to be my last bird photographs of the trip and a fine way to finish.
If you look back up this post at the variety of photographs taken in a single day it shows was an amazing place Ultima Frontiera can be for the wildlife photographer,

The following morning, it was time to wave goodbye to Danube Delta and make the long journey home. We all decided we would try and squeeze in one more brief Golden Jackal session and we would literally have around 30 minutes in the hide. A heavily overcast sky and a jackal that ran in and ripped the staked carp from the ground in one move meant that the few photographs taken ended up in the computer trash bin. However, it was good, even though very briefly, to see a jackal for one last time before we left.

The journey home was a reverse of the one coming to the Delta with a combination of boat, minibus, two planes and a car before I was putting the keys in the front door 18 hours later. What a superb and memorable trip it had been spent in great company with some truly wonderful and memorable wildlife encounters.

So I would like to express a big thank you to a number of people:

• Rene, Paul and Kevin for their great company. 
• Zoltan and Luca for their tireless efforts.
• Sakertour (website here ) for another brilliantly organised trip
• Skua Nature (website here ) for making the stay at Ultima Frontiera such a pleasure
• The chef at Ultima Frontiera for not serving fish!

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