[Reversing] Bypass

brigante

I create the post to collect all the ideas about the challenge. obviously without giving spoilers

clubby789

Pretty cool challenge, learned some new tricks. What I did wasn't reversing per se, but it should be possible.

shebi

Nice challenge. I used a disassembler and some breakpoints to get the flag.. But i don't undestand how i could get the flag with static analysis. Someone could pm me?

Baikuya

If someone finds a way to get the flag with static analysis PM me.
I created the Challange and it was meant to use a Debuger like Dnspy

unsux

This was a very simple challenge and basic practice for newcomers in re. i quite like this, kudos Baikuya!

dosxuz

Type your comment> @Baikuya said:

If someone finds a way to get the flag with static analysis PM me.
I created the Challange and it was meant to use a Debuger like Dnspy

That's a huge spoiler in itself

Baikuya

Type your comment> @unsux said:

This was a very simple challenge and basic practice for newcomers in re. i quite like this, kudos Baikuya!

Thank you very much

@dosxuz said:
Type your comment> @Baikuya said:

If someone finds a way to get the flag with static analysis PM me.
I created the Challange and it was meant to use a Debuger like Dnspy

That's a huge spoiler in itself

Well I dont think so. If you read the challange description you can see that you must bypass something....

gu4r15m0

It took me longer to clone and build dnSpy than to do the bypass 😁.
Great tool!! Thanks

gotroot

First time using dnSPY. I had difficulties recompiling the code but found a work around. Overall cool simple challenge. PM for nudge

sparrow1

This challenge was really fun for a complete noob like me. Thanks @Baikuya!

Baikuya

Your welcome

k4wld

Cool challenge, I first tried the other spy, but the obfuscation was "unbreakable" :-). Learned something new.

carbon123

Type your comment> @Baikuya said:

If someone finds a way to get the flag with static analysis PM me.
I created the Challange and it was meant to use a Debuger like Dnspy

I did in fact complete the challenge via static analysis. I'll PM you.

UpasakhaJason

This was fun. I didn't know much about .NET and reversing it, nor did I know much about the tools to do it, so this was a very nice way to get to know them both.

jackotfd

If anyone could PM me and help me with this I'd much appreciate it. This is my first time reversing and I can understand the code, but I can't seem to figure out certain components.

Skybreaker

Type your comment> @pythonier5001 said:

If anyone could PM me and help me with this I'd much appreciate it. This is my first time reversing and I can understand the code, but I can't seem to figure out certain components.

I really need the help as well.

EDIT: Actually this was easy, and very nice. This was my first RE challenge. Feel free to DM me if you need help.

r3v3rs1ve

I'm a very beginner in CTFs so I'm with some difficulty to solve it. I was trying to hack the .exe file through radare2, but it was so difficult. So I read here that you guys were using something like dnSpy, but I'm in Linux and I can't install it. Is there some tool similar to dnSpy to Linux? I saw on the internet a guy that solved this problem using OllyDbg as well, but I'm trying to use it with wine and when I run the Bypass.exe OllyDbg crash. An alternative to OllyDbg in Linux is the edb-debugger, but when the program print "Enter a username:" edb-debugger crash too.

hackergk

Its easy with basic reverse and basic logic

IR0nIVI4n

Type your comment> @Baikuya said:

If someone finds a way to get the flag with static analysis PM me.
I created the Challange and it was meant to use a Debuger like Dnspy

@Baikuya why create a challenge that requires a specific tool to solve? Just curious. I am using IDA disassembler to solve it and it's not working. It says processor 'cli' is not included. So I have to install and use a tool like Dnspy. This is why I am curious.

IR0nIVI4n

Type your comment> @Baikuya said:

If someone finds a way to get the flag with static analysis PM me.
I created the Challange and it was meant to use a Debuger like Dnspy

I use kali linux and I am running dnSpy with wine. In dnSpy, I am getting an error:
Could not start the debugger. Make sure you have access to Bypass.exe Error: Couldn't find the CLR dll file
Can you help?

Borris

Struggling with the Decompiler, dnSpy, usage. I have found the logic to bypass but could not edit the decompiled code.
Any kind of help related to dnSpy would be appretiated.

LateComerz

I'm in the same boat, can't edit the code. New to dnspy

Borris

Just did it.

No need to edit anything in the code. Just play with the code using Local Variables.

Baikuya

Type your comment> @IR0nIVI4n said:

Type your comment> @Baikuya said:

If someone finds a way to get the flag with static analysis PM me.
I created the Challange and it was meant to use a Debuger like Dnspy

@Baikuya why create a challenge that requires a specific tool to solve? Just curious. I am using IDA disassembler to solve it and it's not working. It says processor 'cli' is not included. So I have to install and use a tool like Dnspy. This is why I am curious.

There are other debuger as well. I just like using Dnspy cause I'am used to it

Baikuya

If someone is stuck you can DM me

4kanesora

Basic but high quality, makes me learned something about IL

DeathR00T

am stuck a little i see some cipher generator but am not sure what the result is am i in the right track ?

Civero

Great work @Baikuya ! A simply but intereresting challenge.

Thanks again!

Baikuya

Type your comment> @Civero said:

Great work @Baikuya ! A simply but intereresting challenge.

Thanks again!

Thanks

mnqn

Once I figured out how dnSpy works, I rather quickly obtained the flag. This challenge is probably very good to get an introduction into using dnSpy. Was kinda cool. Thanks @Baikuya

Sadly I was not able to get the flag the static way yet. Would anyone like to give me a hint on how to do so via DM?

Ty.

DeathR00T

great challenge learned a lot about using dnSpy