Cyber FastTrack Spring 2020 CTF Writeups
🗣tsuto

Thank you so much! I made top 100 but with only about 50% complete and there were some that were on the "tip of my tongue" for hours but I couldn't secure the flag. First individual CTF for me so it was a learning experience but overall I had a blast.

This has been really helpful for me to learn from! Congrats on 1st and thanks a ton!
👤SentientOwl_


🎖@malwr

Cisco Password Cracking and Decrypting Guide
🗣InfosecMatter

For type 7 passwords, you can create a key chain with a key-string 7, then do a show key-chain and it will output the type 7 password in cleartext
👤clearmoon247


🎖@malwr

X86 Inline Assembly
Hello!
I'm new to inline assembly, whilst I do have experience with assembly, it is mostly geared towards programming micro controllers. I'm trying to get an assignment done, and I have been researching inline assembly. My goal is to successfully implement the functionality of what getchar and putchar would do using inline assembly.(Reading a character from stdin, and putting a character on stdout).
I don't know if this means anything but I'm running this on a Linux machine, compiling with gcc.
Apparently it uses AT&T style as opposed to Intel style, This must use x86 inline assembly.


I'm trying to get the steps down.
Write to std_out

It seems I have to load, register %%eax with 4 (the call for sys\_write).
Load %%ebx with the file descriptor, in this case 1.
Load %%edx with the size, in this case 1.
Load %%ecx with a const char *, a pointer to the character.

My first implementation is here:

int main()
{
char p = 'p';
int ret;
__asm__ __volatile__(
"syscall"
:"=a"(ret)
:"a"(4), "b"(1), "c"(&p), "d"(1)
: "memory"
);
return 0;
}

This code above doesn't output anything, but ret is equivalent to -14/

A second implementation, without using extended Assembly
int main()
{
char c = 'c';
char * pointer = &c;
__asm__ __volatile__(
"mov $1, %%ebx\t\n"
"mov $1, %%edx\t\n"
"mov %1, %%ecx\t\n"
"mov $4, %%eax\t\n"
"syscall"
:
:"r"(pointer)
:
);
// printf("foo+bar=%d\n", foo);
return 0;
}

This code doesn't compile, I get a invalid 'asm': operand number out of range.


I'm trying to work through this before attempting writing putchar, as I may have foundational errors.

I'd appreciate any possible aid/hints!


Thanks in advance!
🗣StandardSBUStudent

Are you compiling for 32-bit or 64-bit? They have different system call numbers and calling conventions.

For 32-bit: Pass parameters in eax/ebx/ecx/edx (i.e. syscall number in eax) and use int $0x80 to execute. sys_write is 4.

For 64-bit: Pass parameters in rax/rdi/rsi/rdx and use syscall. sys_write is 1.

For your second example note that the first operand is %0. See here
👤0xa0000


🎖@malwr

Saudi spies tracked U.S. phones using flaws the FCC failed to fix for years
🗣clash1111

Let me guess - it has something to do with an ancient SS7 vulnerability they should've fixed ages ago.
👤deadface008

lol thats what you get for leaving holes open so you can keep eyes on your citizens
👤d33pnull

And peiple want to end end-to-end encryption? Like fuck off.
👤superking75


🎖@malwr

Reverse Engineering Introduction Walkthrough - Intro_Rev/Rev1 CSCG 2020
https://youtu.be/28JHPOUZvDw

#ELF binary analysis, with lots of tools introduced

🎖@malwr

Shodan Command line A Step-by-Step walkthrough
Shodan Command line in this article and video, I show you what you can do, and the benefit of using the Shodan command line in your terminal. Searching for Vulnerabilities to port scanning, there is an incredible amount possible with Shodan.

Article:

https://hackingpassion.com/shodan-command-line-a-step-by-step-walkthrough/

Video:

https://youtu.be/ZAyfWtF0-VI

https://preview.redd.it/qex79jcpdsp41.png?width=1299&format=png&auto=webp&s=794a656483153c2b72cfafec337bd64d0bc0cd48
🗣BullsEye_0


🎖@malwr

I created a small tool to show basic information about a portable executable to improve my understanding of portable executables. Any suggestions or ideas for improvements?
🗣Shepy-5rDUgP9W

What can it show at the moment?

It would be great to have something open source that measures up against Portable Executable Scanner (pescan).
👤wassssaw


🎖@malwr

Stack Overflow goes to dark side!
🗣im-here-to-lose-time

They already crossed to the dark side couple months ago (Monica affair).
👤Haarteppichknupfer


🎖@malwr

"RDP to the Internet has grown significantly over the past month (41.5%)"
🗣limakzi

What can go wrong? :)
👤limakzi


🎖@malwr