Tags: scripting cryptography
Rating:
Source pt1
--------------
```
Challenge:
ssh [email protected] -p 31337 (or 31338 or 31339). Password is sourcelocker
Here is your babybuff.
```
Never had any experience with pwn without having a binary file (Also my first successful pwn challenge), however, I figured it worked out the same way as most binary exploitation did.
When we write a couple of passwords to the file, it always seem to show "Pass auth failed.", and close out of the shell.
However, when we type spam more characters, such as:
```
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
```
The only output seems to be "Connection to source.wpictf.xyz closed." So that seemed suspicious because we want a ``` Pasword auth failed ```, which felt like an overflow error.
So I decided to brute-force my way in by determining the right amount of ```A```'s I should be writing until I make my way in, which were 111 A's, or
```
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
```
Which outputs
```
#define _GNU_SOURCE
#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>
#include <string.h>
//compiled with gcc source.c -o source -fno-stack-protector -no-pie
//gcc (Ubuntu 7.3.0-27ubuntu1~18.04) 7.3.0
//flag for source1 is WPI{Typos_are_GrEaT!}
int getpw(void){
int res = 0;
char pw[100];
fgets(pw, 0x100, stdin);
*strchrnul(pw, '\n') = 0;
if(!strcmp(pw, getenv("SOURCE1_PW"))) res = 1;
return res;
}
char *lesscmd[] = {"less", "source.c", 0};
int main(void){
setenv("LESSSECURE", "1", 1);
printf("Enter the password to get access to https://www.imdb.com/title/tt0945513/\n");
if(!getpw()){
printf("Pasword auth failed\nexiting\n");
return 1;
}
execvp(lesscmd[0], lesscmd);
return 0
}
```
Thus, our flag is ``` WPI{Typos_are_GrEaT!} ```
-------------
Strings
-------------
```
Challenge:
A handy tool for your RE efforts!
made by AWG
File from https://drive.google.com/open?id=1Hr30UBpwKEbt5UF4w2GzfXnVDXoCRVIs
```
When executing the program, it worked the same way as the ```strings``` command would do. But what if we strings the file? So I tried to take a look at the file's functions.
Ooh!, so our flag is ```WPI{What_do_you_mean_I_SEE_AHH_SKI}```
-------------
Jocipher
-------------
```
Challenge:
Decrypt PIY{zsxh-sqrvufwh-nfgl} to get the flag!
made by Samantha Comeau
https://drive.google.com/open?id=1MKcNvHuFCo8vsHZgKOOT0vWddfIzRFk1
```
After getting the required file, we were supposed to decrypt ```PIY{zsxh-sqrvufwh-nfgl}``` to supposedly get out flag. I wrote a small bash script to retrieve the flag.
```
# !/bin/bash
for i in {1..100}
do
./jocipher.pyc --string "PIY{zsxh-sqrvufwh-nfgl}" --shift $i --decode | grep WPI
done
```
``` ./jocipher.pyc --string "PIY{zsxh-sqrvufwh-nfgl}" --shift 48 --decode```
Where our reasonable output is ```WPI{xkcd-keyboard-mash}```
------------
Webinspect
------------
```
Challenge:
Something is lurking at https://www.wpictf.xyz
```
They redirect you to the site. where if you open up the source code, you'll find
``` WPI{Inspect0r_Gadget} ```
------------
Getaflag
------------
```
Challenge:
Come on down and get your flag, all you have to do is enter the correct password ...
http://getaflag.wpictf.xyz:31337/ (or 31338 or 31339)
made by godeva
```
The site starts with
I started with some simple SQL injections such as ``` ' OR 1=1-- ``` or ``` ' OR 1=1# ```, but I didn't get anything out of that. However, after I inspected the source code, on the comments, it showed ``` SGV5IEdvdXRoYW0sIGRvbid0IGZvcmdldCB0byBibG9jayAvYXV0aC5waHAgYWZ0ZXIgeW91IHVwbG9hZCB0aGlzIGNoYWxsZW5nZSA7KQ== ```, which in base64, translates to
``` Hey Goutham, don't forget to block /auth.php after you upload this challenge ;) ```, aha! so when I went to http://getaflag.wpictf.xyz:31337/auth.php it gave me this psudocode
```
// Pseudocode
$passcode = '???';
$flag = '????'
extract($_GET);
if (($input is detected)) {
if ($input === get_contents($passcode)) {
return $flag
} else {
echo "Invalid ... Please try again!"
}
}
```
Because I didn't know to much about PHP, but after reading some functions, I [stumbled](https://stackoverflow.com/questions/829407/what-is-so-wrong-with-extract) on how the extract function is very vulnerable due to how it can replace an element in an array. So after experimenting and having a small knowledge of address object exploits, I came up to an idea since ```$input === get_contents($passcode)```, and the address bar shows the query, I changed input to a null value and also wrote a passcode = null, resulting in
```http://getaflag.wpictf.xyz:31337/?input=&passcode=null```. and our result should have given us
However, you get rick roll'd after seeing clicking on the link, so when I inspected the source code again, it gave me the flag!
```WPI{1_l0v3_PHP}```
------------
Chirp
------------
```
Challenge:
made by Justo and siege
file from https://drive.google.com/open?id=1lcdC9qVBKtSfxOPWLbWd8kAYnPEoSZQb
```
For this challenge, you had to look at a photo of this bird
At first, I thought it was steganography, but I later realized that recon was not supposed to be a steg challenge. So after connecting the title of the challenge and the picture of the bird, I found that the image is depicting an image of Twitter. I went to the sponsor's Twitter page and got the flag.
``` WPI{sp0nsored_by_si3ge} ```
------------
