All Questions

Is there any disassembler (not only a live debugger) second to IDA in capabilities? IDA is wonderful, and somewhat amazing in how robust and useful it is for reversing. However, it is quite expensive ...

It seems that a popular use of software reverse engineering skills is to reverse malicious code in an effort to build better protection for users. The bottleneck here for people aspiring to break ...

I have GDB but the binary I want reverse engineer dynamically has no symbols, that is when I run the file utility it shows me stripped: ELF 64-bit LSB executable, x86-64, version 1 (SYSV), ...

From time to time, when disassembling x86 binaries, I stumble on reference to PLT and GOT, especially when calling procedures from a dynamic library. For example, when running a program in gdb: (gdb)...

Learning the GDB commands is on my bucket-list, but in the meantime is there a graphical debugger for *nix platforms that accepts Windbg commands, and has similar functionality? For example, the ...

I try to understand the process of memory segmentation for the i386 and amd64 architectures on Linux. It seems that this is heavily related to the segment registers %fs, %gs, %cs, %ss, %ds, %es. Can ...

I was recently analyzing a web page that contained some highly obfuscated JavaScript - it's clear that the author had went through quite a bit of effort to make it as hard to understand as possible. I'...

I know how to reverse engineer normal android APKs using tools like APK-tool anddex2jar but i don't know how to work with obfuscation. Can anyone help or atleast provide some pointers? I know this ...

I've recently managed to isolate and archive a few files that managed to wreak havoc on one of my client's systems. So I was wondering what software and techniques make the best sandbox for isolating ...

I was reading a discussion about dumping a processes part of a process's memory and someone suggested using DLL injection to do this. I'll be honest in that I don't really understand. How does DLL ...

Can someone give a list of websites with good (and free) reverse engineering training exercises ?

I browsed a lot, but can't find any resources for reverse engineering an ipa file (iPhone application). Is there any method to reverse engineer an ipa file to its source? I've tried to rename it to ...

I recently saw an older talk by Sergey Bratus and Greg Conti by the name of Voyage of the Reverser: A Visual Study of Binary Species. Are there any opensource/free tools that one could use to see ...

I see this instruction in the beginning of several Windows programs. It's copying a register to itself, so basically, this acts as a nop. What's the purpose of this instruction?

The ATmega microcontrollers generally have two lock bits, LB1 and LB2. One prevents further programming, and the other prevents the flash being read back. If both are set, the chip needs to be erased ...

I'm looking for a tool like Beyond Compare, meld, kdiff, etc. which can be used to compare two disassembled binaries. I know that there's binary (hex) comparison, which shows difference by hex values, ...

I am using JD-GUI to decompile Java JAR files, but the problem is that it leaves many errors, such as duplicate variables which I have to fix myself and check to see if the program still works (if I ...

Let's say I found 'some' file (might be an executable, might be data, or something else) and want to run or read it. I open this file in a text editor, but the format isn't readable. Examples include: ...

How to understand if exe/dll is written in C++/.Net/Java or in any other language. I tried to use Dependency walker but not able to get required information.

I want to add some functionality to an existing binary file. The binary file was created using gcc. Do I need to decompile the binary first, even though I sufficiently understand the functioning of ...

I find that more and more often binaries are being packed with exe protectors such as upx, aspack etc. I tried to follow a few tutorials on how to unpack them but the examples are often quite easy ...

I've been searching this site and more, but I haven't had much luck. I want to decompile an app to see how part of it works, and I've tried multiple programs. I've tried Hopper, IDA, and some other ...

How could this 32-bit x86 assembly be written in C? loc_536FB0: mov cl, [eax] cmp cl, ' ' jb short loc_536FBC cmp cl, ',' jnz short loc_536FBF loc_536FBC: mov byte ptr [eax], ' ' loc_536FBF mov cl, ...

At the professional level, for what purpose is reverse software engineering used? What software is targeted and why? For reasonably complex compiled code that's doing something novel, making ...

Is it legal to reverse engineer certain features of a closed source application and then integrate those features into a closed or open source application that may be either a commercial or non-...

Are there any tools available to take an already compiled .dll or .exe file that you know was compiled from C# or Visual Basic and obtain the original source code from it?

What tools and techniques exist to either decompile or analyze the bytecode in a SWF file? What resources are available to the reverse engineer to learn more about SWF internals?

When compiling a division or modulo by a constant, my compiler (LLVM GCC) generates a series of instructions that I don't understand. When I compile the following minimal examples: int mod7(int x) { ...

I have an Arduino Uno Rev3. I would like to extract and find out what code is burned on the ROM of the micro-controller board. How do I extract the code from the board? How do I figure out the ...

While reversing a 32bit Mach-O binary with Hopper, I noticed this peculiar method. The instruction on 0x0000e506 seems to be calling an address right below the instruction. What would be the reason ...

In hope this is appropriate I have a Bosch Tassimo TAS2002EE coffee maker that uses T-Disks. Those contain coffee/milk/something else, and a barcode that is supposed to tell the machine how to deal ...

When I am looking at the machine code of an application, are there hints and patterns I can discern from the generated machine code which would indicate which compiler (and possibly version) was used ...

I've been looking for an open-source GUI tool to extract PDF's in an automated way on Windows systems. I've used Didier Steven's tools with great interest for a while, but cannot make sense of how to ...

I have a binary on a Linux (Kernel 2.6) which I can execute, but can't read (chmod 0711). Therefore no static analysis is possible. user1: $ ls -l bin -r-s--x--- user2 user1 bin user1: $ file bin ...

I've seen this referenced in a couple of other questions on this site. But what's a FLIRT signature in IDA Pro? And when would I create my own for use?

When we're doing reverse engineering, we have a few levels of models. One of them is the instruction semantics model, which tells us what every native instruction does to modify instruction state. We'...

Newbie here. From Wikipedia Disassembly is not an exact science: on CISC platforms with variable-width instructions, or in the presence of self-modifying code, it is possible for a single ...

I am struggling on this problem for around three months: How to use disassemblers (IDA Pro and others...) to generate re-assemblable asm code and assemble it back My experience is that: There is NO ...

Having recently watched/read a presentation given by Dave Kennedy at DEF CON 20 [PDF], I'd like to know how to decompile a Python script compiled with PyInstaller. In his presentation, he is creating ...

I'm a software guy through and through. But periodically when I'm taking apart hardware I know to look for JTAG ports and RS232 ports. So far I've always been lucky and have been able to solder on ...

I wanted to see what Microsoft are doing when you click "Restart now" button in their Settings -> Update window on Windows 10: Somehow the results are not the same what is available via ...

The Android java code is compiled into Dalvik byte code, which is quite readable. I wonder, is it possible in theory and in practice to write a decompilation software for Dalvik byte code?

Java and .NET decompilers can (usually) produce an almost perfect source code, often very close to the original. Why can't the same be done for the native code? I tried a few but they either don't ...

If I am building a C++ application and I want to make it more difficult to reverse engineer, what steps can I take to do this? Does the choice of compiler affect this? What about compiler flags, ...

I have seen mentions of SoftICE on various questions throughout this site. However, the Wikipedia article on SoftICE implies that the tool is abandoned. Searching google, I see many links claiming to ...

Are there any scripts and/or online tools that can reverse the effects of minification? I'm specifically looking to unminify a minified JavaScript file. Variable renaming is not a big issue, I want ...

I just found a strange instruction by assembling (with gas) and disassembling (with objdump) on a amd64 architecture. The original amd64 assembly code is: mov 0x89abcdef, %al And, after gas ...

I'm currently a high school sophomore. I haven't really done much on the RCE of malware, I've unpacked zbot and rbot, and looked at how they work, but I can manipulate practically any game to my ...

I'm a newbie and just got into RE. I got a ELF 64-bit LSB executable, x86-64. I'm trying to reverse it. First I tried to set a break point on line 1 using gdb ./filename break 1 The gdb says No ...

How comes that text diffing tools like diff, kdiff3 or even more complex ones usually fail at highlighting the differences between two disassemblies in textual form - in particular two related binary ...