Instruction at 0x00401310 checks if there is a command line argument. There is an irritating sleep function, you could either NOP the function or change the argument to 0. Next there is a reference to 0x417550 and then a Jump to the actual code.

On inspecting the memory at 0x417550, a plain text is received (274 bytes) when XOR-ed with 0x55.

“Good job! Keep going….Good luck!”

Next, it checks that the name of the program is princesswarrior.exe, you can just bypass that or rename the executable, then the length of the string is checked, it should be 0x32.

Lastly, the fun part, so

x1 = your string.

x2 = string at 4174E8

x3 = string at 417664

So the key => x1  = (x3 xor x2) – 12

For example if example@gmail.com sends an email to username@facebook.com it will be sent to username@gmail.com (considering the person owning username@facebook.com has set username@gmail.com as his primary email address.) However, if the person clicks on reply, the email is sent as username@gmail.com. This is the default setting.

However, gmail allows you to send mail as any id as long as you can click on a link send to that email id. 3:)

Just follow these steps to be able to send as username@facebook.com :

1. Click on Settings Button in your gmail account > settings > Accounts and Imports

2.  In accounts and imports click on ‘add another email address you own’

3. Enter the your facebookusername@facebook.com and uncheck “Treat as an alias”.

4. Click Next and in the next set of options select “Send through gmail.”

5. Wait for the confirmation email to be forwarded to your gmail id and once it arrives click on the link and close this pop up!

You are done and good to go! Just click on compose and you should be able select your facebook id to send emails from!

Thanks

All right so the solution that I came up with; was developing a font, with which I can exactly replicate my handwriting and can simply convert the code by selecting that font. :)

The above pic is a sample conversion. The results are super awesome believe me. This picture is a screen shot of the very first attempt that i made, the first line is written in Calibri and the second in “JUGAAD”  and with a little rework one can do wonders.  Especially, for a subject like compiler where you had to write “code” in your handwriting this is extremely full proof! ;)

Now comes the main question!! How! You’d probably already know it and if you don’t, believe me its very VERY easy!.

Step1. Download a template file from www.paintfont.com by clicking on “create template”. Basically this template contains small boxes with characters printed inside them in light gray color. The characters you want to create are already selected if you want anymore characters you can add those as well!

Step2. Take a print out of the template and fill the template. Take a bold marker and overwrite the light gray characters.

Step3. Now scan the two files. For instance here are the files I created.
FILE 1:

FILE 2:

Step 4 : Now you need to upload these files at http://www.paintfont.com/#tabUpload, select OTF format and click on “Send File”.

Step 5 : The font is ready and you get a screen like :

Step 6: Now just download the myfont.otf and on the downloaded file, right click > install. You can now go to your favorite editor and type in your handwriting! :)

It is about a minor project that i recently completed. That is writing a virtual machine to slow down the process of reverse engineering. This is not a tutorial to do the same however I have included the presentation that i used during the final presentation, the PDFs for System Design and Sample Runs and one step by step sample run.

#Presentation

#Code

#Sample Run

In this sample run I am going to implement the POC expansion algorithm that was the final program that was written for OIVM.1. Make sure bootrom.txt and OIVM.exe are in the same folder.
2. Open the Bootrom.txt using a Hex Editor (example : Hex Workshop) and write the following hex stream to it.

3F 11 25 00 2F 08 3F 38 3F 38 41 3D 09 1B 3C 4C 21 25 00 2F 14 7C 67 63 55 64 61 38 67 7C 63 38 55 64 61 38 37 41 3D 15 C9 45 3F 11 3F 12 18 68 3C 25 00 2F 08 12 86 C5 38 41 3D 09 00 02 04 06 08

3. Save the file. This is basically in the format of [STUB][Compressed Code]. The stub is 60 Bytes long and extends till the 0x09 in the second line of the hexadecimal stream. The parallel assembly for this code is as follows :

[EXPANSION STUB]
scanf(“%d”,&STACK[SP])
MOV A,STACK[SP]
FLAG=A-ROM[++IP]
JE 8 BYTES
scanf(“%d”,&STACK[SP])
++SP
scanf(“%d”,&STACK[SP])
++SP
–A
JMP -9 BYTES
MOV B,ROM[++IP] //STUB LENGTH
A = fileLen
A=A-B
FLAG=A-ROM[++IP]
JE 14 BYTES
MOV C ,ROM[B]
MOV D,SP
MOV SP,C
MOV C,STACK[SP]
MOV SP,D
MOV STACK[SP],C
++SP
MOV D,SP
MOV C,ROM[B]
MOV SP,C
++SP
MOV C,STACK[SP]
MOV SP,D
MOV STACK[SP],C
++SP
++B
–A
JMP -21 BYTES
ROM=(char *)realloc(ROM,ROM[++IP]) //FILE EXPANDED
scanf(“%d”,&STACK[SP])
MOV A,STACK[SP]
scanf(“%d”,&STACK[SP])
MOV B,STACK[SP]
MOV SP,B
MOV C,ROM[++IP]
FLAG=A-ROM[++IP]
JE 8 BYTES
MOV B,STACK[SP]
MOV ROM[C],B
++C
++SP
–A
JMP -9 BYTES
[COMPRESSED FORM]
00 02 04 06 08

4. Now run the program.If however you dont speak assembly that doesnt matter here is the algorithm for it :

1. Enter the Number of elements in the dictionary.
2. Enter the dictionary.
(Dictionary is stored on the stack)
(The dictionary is looked up for values corresponding to compressed code)
(The new Values are updated over the stack)
3. Enter the New Size.
4. Enter the SP (which could have been hardcoded as well)
(The code expands)
(The execution is now passed on to the expanded program)
5. Enter the first element. Hit Enter.
6. Enter the second element. Hit Enter.
7. The sum is Displayed.
8. OIVM halts.

Results/Output

#Thanks

Special thanks to Mr. Atul Alex Cherian, Ms. Nishtha Jatana and Ms. Kritika Sobti.

Hi, non technical reader.

Introduction

So basically this is the small program I wrote, which we are going to play with. In this program there are two functions : func1() and func2(). func1() is called from main, but func2() is never called.

So our aim is to execute func2 at run time.Here is the first run :

As you can see we do not go inside func2.

Reverse Engineering solution The first and the lot easier approach to this is, a RE solution. In this solution i just change some return addresses on the stack and we are done. Lets go step by step.

Step1 : Loading the program in OllyDbg

As can be seen there are three functions main, func1 and func2. These are indicated by the square brackets. The order of these functions is func1, func2 and lastly main.

Step2 : Now I am going to put a breakpoint on func1 and then observe the stack.

We have two images here the first one represents the assembly view of print2.cpp when i hitthe breakpoint and the second one represents the stack when I hit the breakpoint. In figure 1 it can be seen that the func1 starts at 401334 and it(the address) is in read with black background. Which indicates that we have hit the breakpoint. In figure two we can see that the return address for func1() is 0040139A. If we look up this address in the assembly dump, it is the one just after func1() is called that is 401395. Hence, things are fine here, the function always returns to the immediate expression after a call to it. So we have two deductions from here. First that the return address is 40139A which can be changed to make the func1() jump somewhere else. and secondly that this address is placed on the memory address starting 28FF0C.  

Step3 : Now we are going to edit 40139A to 401359 so that we can jump over to func2().

After the modification even the comment changes to print2.00401359, which suggests that it is call. And as expected we enter the func2().

However this is not enough. In a similar way we have to edit the return address of func2 to 40139A which was the original return address of func1. Now to be able to identify where is the return address of func2, we single step through func2 till we reach RETN.

Step4 : Here the top address on the stack is the return address for the stack. We need to change this address. In order to return and exit normally.

As can be seen on the stack 0028FF10 is the address where the return address 00403050 is stored. We modify this and then run the program.

We are able to do it neatly. :)

Program Solution

Now the RE solution was though easy, it wasn’t automated, and i had no fuckin idea about how do i make a permanent modification. What i mean here is like if you want to completely change an instruction you can do that and simply save changes to the new executable. But the stack is a dynamic memory region, it is not a part of the exe file that you save. So there was something more, some workaround that was needed. And thanks to Atul Alex Cherian, who told me about loader. So a loader is basically a program that lets the entire exe load in memory and then plays around with it. I first thought about using a tool for this, but then why not just code this shit out. So here is the algorithm that i followed for this.

Step1. Use fread to read the bytes of print2.exe to an array.

Step2. In this array modify the byte that represents beginning of func1 to CC (breakpoint).

Step3. Save this array to a new myf.exe

Step4. Detach pointer to myf.exe and open process myf.exe as a DEBUG_PROCESS

Step5. Waitforadebugevent and use a simple condition to check that it orignates from the one that you forced.

Step6. On receiving the EXCEPTION_BREAKPOINT DEBUG_EVENT suspend the thread using process information of myf.exe

Step7, Now change the CC that you placed to the original byte

Step8. Getthreadcontext of this thread and access the context structure to decrement EIP.

Step9. Now change return addresses of func1 and func2. For func1 only one byte is edited and for func2 one has to edit 2 bytes.

Step10. Resume thread. Myf.exe should exit after you press the first enter, then loader.exe should exit after you press the second enter. Here is the code :

Here is the screen shot showing its execution.

And special thanks to Dhanesh sir. :)

H3LL Y34H! :)

1. Symbiosis Centre for Information Technology (SCIT)

MBA in (ITBM) with Elective Informations Security Management
[Link Here]

2.Amity Noida

I am not very sure if Amity still provides an Mtech in Information Security & Cyber Forensics [Link Here]. They did not provide any details for the same online.

3.Amrita School Of Engineering

3.1 Mtech in Cyber Security
[Link Here]

3.2 Mtech in Cyber Security Systems and Networks

3.3 Dual Degree Programs :

Students pursuing mtech in cyber security are eligible for :

1. M.Tech-MS with University of New Mexico, USA [Link Here]
2. Dual Degree Program with Vrije University, Amsterdam, Netherlands[Link Here]

4. Indraprastha Institute of Information Technology, Delhi

4.1 Mtech in computer science with specialization in Information Security.

These subjects include and are not limited to

[link here]

• Secure Coding (CSE500)
• Distributed Systems Security (CSE530)
• Foundations to Computer Security (CSE545)
• Applied Cryptography (CSE546)
• Digital and Cyber Forensics (CSE645)
• Mobile and Cellular Network Security (CSE647)

The institute also offers a PhD in Privacy and Security.

5. International Institute of Information Technology, Hyderabad

5.1 M.Tech in Computer Science and Information Security

[Link Here]

 6. IGNOU courses

6.1 Post Graduate Diploma in Information Security (PGDIS) [Link Here]

6.2 Advanced Certificate in Information Security (ACISE) [Link Here]

7.SRM University

#include “stdafx.h”
#include “windows.h”

void antidebug();
void antidebug()
{
HMODULE lib;
FARPROC _ZwSetInformationThread;
lib = LoadLibrary(“ntdll.dll“);
_ZwSetInformationThread = GetProcAddress(lib, “ZwSetInformationThread“);
(_ZwSetInformationThread)(GetCurrentThread(),0x11,0,0);
MessageBox(NULL, “Debugger Detached“, “Debugger Detached“, MB_OK);
}

int _tmain(int argc, _TCHAR* argv[])
{
antidebug();
MessageBox(NULL, “Double Check…“, “Double Check“, MB_OK);
return 0;
}

Before I get into the BUGs lemme just try and explain what is happening here, so we are basically loading a handle to ntdll.dll by calling the LoadLibrary process and then we load the callback to _ZwSetInformationThread which is of datatype FARPROC[more on FARPROC] then we call ZwSetInformationThread routine which has four parameters as per http://msdn.microsoft.com/en-us/library/windows/hardware/ff567101%28v=vs.85%29.aspx .

The firstparameter is the handle to the current thread and since we want to run this function within our program we use the GetCurrentThread() function call which returns a handle to the current thread. Next is a value 11. This is basically the value because of which the debugger would get detached from the process. Now how did i get this value. As per documentation on msdn the second parameter is of the enumeration type _THREADINFOCLASS which is as follows [source] :

typedef enum _THREADINFOCLASS {
ThreadBasicInformation,
ThreadTimes,
ThreadPriority,
ThreadBasePriority,
ThreadAffinityMask,
ThreadImpersonationToken,
ThreadDescriptorTableEntry,
ThreadEnableAlignmentFaultFixup,
ThreadEventPair_Reusable,
ThreadQuerySetWin32StartAddress,
ThreadZeroTlsCell,
ThreadPerformanceCount,
ThreadAmILastThread,
ThreadIdealProcessor,
ThreadPriorityBoost,
ThreadSetTlsArrayAddress,
ThreadIsIoPending,
ThreadHideFromDebugger,
ThreadBreakOnTermination,
MaxThreadInfoClass
} THREADINFOCLASS;

So ThreadHideFromDebugger is 17 which is basically 11 in hex. And the remaining two parameters are obviously not of importance to us. :D

Now coming to the bugs. “|17|error: too many arguments to function|” But MSDN said that it needed four :O and now i started removing one parameter at a time and the function ran when i did not pass any arguments. After having searched a lot! The only solution that i could think of was to use the asm function and pass these arguments manually.

So i made the following changes.

(_ZwSetInformationThread)();
GetCurrentProcess();
asm(“pushl 0“);
asm(“pushl 0“);
asm(“pushl 0x11“);
asm(“pushl %eax“);

Oh and by the way the assembly syntax utilized on GCC is the AT&T asm. So yeah! I had to first read that because i have being doing the intel format. I read [this]

So this was some success because atleast the exe compiled, i had already though that now i would easily debug everything on OllyDbg and get it through. But this is what GCC(or i) had done to the code. :

So this wasnt the best solution.But it was some success since i was atleast able to compile the exe now and look it up in Olly (Somehow i am more comfortable with that.)

I decided that since the value passed as the handle to the process is the only thing that i do not know lemme pass other values by modifying the assembly code manually in Olly and changed the code to the following :

HANDLE hndle = GetCurrentThread();
(_NtSetInformationThread)();

The exe did compile and i was getting the pop up messages too.

Next thing was to immediately load this exe into my dearest OllyDbg and get started. Here is the very first look.

You can see that a call gets made to GetCurrentThread at 00401365 and the value is returned into EAX which is them moved to our variable “handle” (EBP-14). So after a couple of runs i realized that this value was always the same and always returning FFFFFFFE i am not sure if this is a fixed constant for a each system or is it just the local handle to every thread. But this is what it was in the case that I had in front of me. Then later you can see that a different value is moved into EAX and at 00401370 we make a call to that address (call eax) hence this is the handle to the ZwSetInformationThread.

So far so good. Next i had to modify the code so that i could push values to the stack before the call eax is executed. If you at the address 00401362 you would see that MOV EBP-10,EAX instruction is executed just after GetProcAddress so basically this is the place where the handle to ZwGetInformationThread is placed on the stack hence we can only modify the code after this. That is from 401365 to 40136D where the value is pushed back into EAX. (Or we could NOP both of these so that the value remains unchanged)

So here are the modifications that i did, wait and after this modification i clicked analyse code. So you’d see that now Olly recognizes this as a function ^_^

so we have obviously overwritten the call to GetCurrentThread but the code seems to fit just fine! :)

Now do you see a push -2 at 0040136B i had assembled PUSH 0xFFFFFFFE. :) And also since this is windows you would have to push the last argument first… just in case you did not know this.
Now before you run the code remember to save all modifications to exe because if the code is successful you would be detached from the debugger.
And finally we run the program. We Get the pop ups. And next we are detached from the debugger. :) (The code screen goes blank. Try reloading with << button.
The Blank Screen :

The Error :

H3LL Y34H! B)

I am currently working on anti-debugging techniques which will also be my project for this year in college.Though i know for a fact  most basic anti-debug techniques are  API based techniques, but i am still doing this post because firstly i did not find any working code and whatever non-working code was present was also implemented locally… By the way I am really impressed by the work compiled by Tyler Shields in 2009 and he has put up some of the best resources out there!

This post is basically about one of those standard API’s > CheckRemoteDebuggerPresent function. Now there is enough stuff on msdn and other websites that you can find about its implementations and about the working of the function however for some reason they did not work for me! So here is what finally worked. And I have done a remote process example too.

Implementation for process locally 

#ifndef _WIN32_WINNT
#define _WIN32_WINNT 0x0601
#endif
#include<windows.h>
#include<stdio.h>
#include<conio.h>

int main()
{
BOOL pblsPresent = FALSE;
HANDLE hndle = NULL;

CheckRemoteDebuggerPresent(GetCurrentProcess(),&pblsPresent);
if(pblsPresent){
printf(“Being Debugged\n“);
}
else{
printf(“Not being debugged\n“);
}
getch();
return 0;
}

Implementation For Remote Process (with PID 2800)

#ifndef _WIN32_WINNT
#define _WIN32_WINNT 0x0601
#endif
#include<windows.h>
#include<stdio.h>
#include<conio.h>

int main()
{
BOOL pblsPresent = FALSE;
HANDLE hndle = NULL;

hndle=OpenProcess(PROCESS_ALL_ACCESS,FALSE,2800);

if(hndle){
printf(“Done getting a handle \n“);
}else {
printf(“Invalid PID \n“);
}
CheckRemoteDebuggerPresent(hndle,&pblsPresent);
if(pblsPresent){
printf(“Being Debugged\n“);
}
else{
printf(“Not being debugged\n“);
}
getch();
return 0;
}

For : Extremely simple to cook. Hygienic. Customizable.

Against : Consumes way more time cooking, than finishing it or buying and eating. Doesnt taste upto the mark(6.5/10) .

Verdict : You can give it a shot if you like cooking. Not for you, if, taste is your only interest. :D

#Orginally, created and put up by 2nd Shift IT/CSE ~ MSIT  for farewell of batch 2009-2013.

#Reused by BCA :

I hope they did not name their farwell Au Revoir :D