Questions tagged [static-analysis]
Static analysis is the analysis code without actually executing it. This is in contrast to dynamic analysis which executes the code.
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questions
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Binwalk, what's advantage of "Show results marked as invalid"?
I'm trying to understand -I option in binwalk. It provides some interesting output yet it isn't clear if these results are "invalid" or if they are valid results of a special type.
DECIMAL ...
2
votes
1answer
78 views
Split variable in Ida Pesudo Code
Sometime the meaning of variable has been changed on the function.
For example from Ida pseudo code:
a = price
....
a= tax....
In the beginning of function a was price and after that a is tax.
How ...
2
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1answer
119 views
What is "nullsub_XXX" in vtable in IDA
When I looking in a vtable structure in IDA pro, I know that ___cxa_pure_virtual means that the function is virtual.
But what does nullsub_XXX mean in a vtable structure?
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0answers
31 views
Tools to generate code to hidde hardcoded critical data
I have retrieve a code file related to security topic, that contains a piece of code to protect harcoded value of RSA key against static analysis:
// Byte values of encrypted key
//121, 217, 79, 9, ...
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2answers
64 views
Not Understanding the FU540 Boot Process
I'm reading the manual for the SiFive FU540-C000 trying to understand the boot process, and I'm not making sense of the initial steps after power on.
I'm using MSEL = 1111 based on the recommendation ...
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0answers
110 views
Pascal string representation in Hex-Rays Decompiler of IDA Pro
I'm trying to prettify a representation of Pascal-string "Could not access file "" in Hex-Rays decompiler's output. As you can see below,
now its type is char[25] due to inclusion of ...
1
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1answer
82 views
Ida Pro doesn't recognize known function
I open statically Arm binary with Ida Pro.
While I reversing I find out some function like strstr and memcpy and etc. That Ida doesn't understand that those function are strstr and memcpy(for example)
...
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1answer
130 views
How do I interpret this double offset?
While looking at that old game I've found a class CStr that is used in an unusual (to me) manner. Most of the times a member of CStr is used, it's done as follows. In both cases, this is a CStr *.
...
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1answer
177 views
What does this function do?
I'm trying to understand what client sends to server. I already did most of the work, but one function left. I can't understand what to do with this function and what it does. I've tried to change ...
0
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2answers
74 views
Format of data in the .code/.text section
I'm attempting to dissect/disassemble a windows PE file under Linux using objdump. On surface analysis, the .code section was disassembled to :
tmp.exe: file format pei-i386
Disassembly of ...
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0answers
66 views
IDA script: How to properly undefine a byte and then redefine code
I'm trying to correct the following instructions in IDA using a script:
jnb short near ptr loc_1C61B1+3
It order to do this I'm running a snippet like this in a script:
ida_bytes.del_value(...
3
votes
1answer
90 views
Determine if the function has try/catch statement via the static analysis
I need to determine if the function has exception handler via static analysis. Initially I thought that if there's SEH handler prolog in the function, then the function should have try /catch. I.e. I ...
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46 views
How can I connect basic blocks seperated by unconditional jmps?
I'm analyzing an obfuscated code which splits its code into multiple blocks seperated by many, many unconditional jmps. Here is a picture of what the obfuscation looks like:
I wrote an IDAPython ...
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0answers
27 views
Why parameters are out side of stack frame ( green) in attached image?
In my assumption, stack frame is between EBP & ESP only. But Stack frame is started from out side of EBP, in the attached image.
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0answers
30 views
Can you strip a mips64 object file?
-strip doesn’t know what this file is but read elf and objdump recognize it read elf gives entry and all the headers. I’m trying to find main() or the start function. Can I strip the file? Do I need ...
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41 views
What is the difference between a file on disk and a file on memory?
Currently, I am learning about the differences between static and dynamic analysis. I have come across this incredible question that has been bugging me: What happens to the file (in memory) when you ...
2
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1answer
187 views
Help regarding XOR game decryption algorithm
I'm currently trying to reverse engineer the decryption algorithm for an old online game, using a chat message packet, as it contains text which is easily recognizable.
I used a packet sniffer to get ...
0
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1answer
79 views
Why might nm find a few undefined symbols that I can't see with xxd?
I'm cross-comparing a few approaches to testing for binaries that import a symbol and I noticed a YARA rule not finding one in sudo that nm + grep could find.
I looked at it in xxd to figure out why, ...
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1answer
147 views
Arrays assembly
I'm reversing my C array's programs where I'm storing numbers in arrays like this...
int marks[5];
marks[0] = 1;
marks[1] = 3;
marks[2] = 2;
marks[3] = 7;
marks[4] = 9;
so the compiler showing me the ...
2
votes
2answers
138 views
Why this ASM represents Virtual Function call?
I'm referring to this question that was asked previously:
Virtual functions call asm
I'm wondering how is it possible to know whether this ASM listing represents Virtual Functions calls? What's in the ...
2
votes
1answer
154 views
Not able to understand the C-switch statement in disassembly
While I'm trying to disassemble my own C code I am stuck in a problem of not understanding how this Switch statement is implemented in assembly code. Can anyone please help to figure it out? This the ...
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1answer
171 views
Difference between \n, \0, \x00 and data from /dev/zero when performing a buffer overflow?
I am working with a binary that involves a buffer overflow on two contiguous memory blocks allocated with malloc. The binary filles up the first buffer with whatever the user inputs and hardcodes the ...
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0answers
108 views
Using GDB to find the address of a buffer in a stripped C binary
I am working with a crackmes binary called Simple Overflow. It has two buffers with sizes 0x10 and 0x8, and it uses malloc to allocate two contiguous memory blocks (see <+25> and <+39> on ...
0
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1answer
69 views
How to simplify a function "calling itself's reference"
I encounter often a function calling itself (in the pseudo code) such as:
result = (**(__int64 (__fastcall ***)(volatile signed __int32 *))lambda)(lambda);
Since the disassembly is call qword ptr [...
0
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1answer
71 views
Is it possible to make a dynamic memory allocated .data segment to static in a file?
Sorry if this is a dumb question I'm new to assembly.
Basically I want to modify a function in a .exe file to return with a different data, but my issue is that the memory location of the data segment ...
3
votes
2answers
99 views
How to figure out functionality when doing Static Code Analysis in ASM?
When doing Static code analysis on a disassembled app, I usually end up seeing many calls to registers (CALL EAX for example), which is constructed in runtime, which leaves me clueless on how to ...
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2answers
92 views
Lifting exported function instructions in PE files
I am trying to automate analysis of instructions within exported functions for a .DLL and need to be able to lift the first few instructions for the entry point of each exported function statically ...
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4answers
131 views
finding sequence of opcode in binary
I have dis-assmebled binary and want to check if it contains particular sequence of opcodes(obtained from other reference binary). how to do that . i know plain byte
level comparison wont work as as ...
0
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1answer
101 views
How can I find a value in Tricore(TC1766) Arch?
I recently work on Tricore Processor, but I have some problems.
With reading memory value. I do not know if I am right or not, but I think a part of flash memory copied to RAM and now in my algorithm ...
1
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0answers
127 views
Delphi mt38 CRC (Tricore 1766 Arch)
I want to calculate CRC32 for Delphi mt38 and found the below assembly algorithm and converted it to C. It seems that this algorithm is defined for n = 256 or 1024. I want to calculate CRC32 for n = ...
3
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0answers
33 views
How can I tell whether or not a given library method is being referenced by a consumer program statically in OOP languages?
Preface: This question is about source code reverse engineering and static analysis. Meaning, there is no built code available but I have access to the source code of the program.
Imagine I'm looking ...
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0answers
114 views
CRC16 Reverse in C166 Arch
Before that I asked about piece of code that used in this algorithm (here). Now I have a bit problem with the rest of algorithm.
So I have to describe this with detail. Sorry if i vast your time for ...
0
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1answer
211 views
Static Binary in Windows
I am learning more about binary exploitation on windows. But I saw while revering a binary that you can create static binaries in windows too just like in Linux. It was really ugly. if I would be on ...
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0answers
43 views
Strange memory allocation behaviour
I'm currently working on a modding library for a particular game, and I have come across a part of the menu system that I can't figure out the purpose of.
The expression in question is this:
unsigned ...
0
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1answer
70 views
Password evaluated from the sum of ASCII letters
After analyzing the code, I have been able to understand and recreate the algorithm used to check if the password the binary takes is correct, but don't know how to solve it (or at least can't think ...
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votes
1answer
277 views
The C166 family code meaning
What the meaning of this code with an explanation?
sub_37C2:
mov r5, r4
shr r5, #14
shl r5, #1
mov r5, [r5+0FE00h] ; DPP0
bmov r4.14, r5.0
bmov r4.15, r5.1
shr r5, #2
rets
; ...
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2answers
150 views
Is manually converting/decompiling x86 source code to C/C++/etc... considered reverse engineering?
I have the source code of an old program written in 32-bit x86 assembler that I am working on manually rewriting in C.
The first time someone asked me about this project I told them I was 'reverse ...
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0answers
53 views
Statically injecting translated NASM assembly into existing ELF binary
I'm trying to statically patching ELF binaries in order to incorporate code that can help provide run-time protection.
In an effort to save time writing and debugging assembly, I took the following no-...
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0answers
62 views
Immediate offset LDR in presumed malloc function looks wrong in static analysis
I am attempting to disassemble a ROM image for a BCM4366C [1] after reading a blog post where researchers reversed some other Broadcom chips [2] . I have analyzed the ROM image in Ghidra and I have ...
0
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1answer
38 views
What is this line and how to remove it
I tried to unpack packed_dll, when the unpack stage done, i dumped unpacked_dll out and start to reverse. I pretty sure this is continuously function of that dll but this line show up. So what is this ...
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votes
1answer
134 views
How can I analyze this code? [closed]
I wanted to analyse the code for some functionality.
in my understanding the code contains a logic handling intents with extras. I want to know how these Works! and also how can I pass extras using ...
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0answers
157 views
Removing/bypassing a BIOS whitelist
I am trying to bypass or erase the BIOS whitelist on my Thinkpad T440p. So far I've
used flashrom and a soic8 clip to dump the bios to a bios.img file
made another dump and compared with diff bios....
0
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1answer
176 views
ida identifies library function as regular function
I'm trying to find libc symbols in some Windows 32-bit application. For some reason, Ida autoanalysis didn't recognized code that comes from libc as "library function", but as a "regular function". ...
1
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0answers
107 views
ARM chip gpio/ identification from firmware code
Device: i was able to recover bricked Chinese IOT a Sous Vide cooker. Replaced damaged capacitor. it works.
it has
ARM soc/mcu/processor
WI-FI (broadcom)
LCD touch screen + 16bit STM mcu.
EEPROM ...
1
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1answer
72 views
methods that have zero usage in jadx?
so i've been reversing this ai assistant app to figure out what kind of forensic data it leaves on local file system. during static analysis with jadx-gui i found some interesting methods that take ...
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1answer
434 views
Dynamic analysis (Frida) reveals instance of a class that doesn't exist in the source code (dex2jar)
I have been diving into an apk's source code, doing both static analysis with Jadx (same as dex2jar) and dynamic analysis with Frida.
I am trying to replicate the method that signs HTTP requests "...
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0answers
40 views
static analysis for identifying backdoors
I am doing a research in identifying backdoors in windows .exe files. Currently I found some methods to detect.
1.String search in .exe
2.find Reffrence .dll and win32 Api calls using import table
...
0
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1answer
1k views
Find functions signatures in Ida?
I didn't understand the subject of find function in Ida via signature.
If I understand well that way helps to recognize libraries functions in static binary(in dynamic binary I can see the functions ...
0
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1answer
88 views
PE file export functions of packed file
I am new to reverse engineering and I am learning about packed files.
I saw that most of the time I can recognize a packed file with a little number of import functions in PE file and not many strings ...
1
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1answer
416 views
Find all syscall in statically Arm Binary
What is the easy and fast way to find all syscall in statically Arm binary ?
Is there any Ida plugin that do that?
