OverTheWire: Natas Level 8 – #appsec #webapp #websecurity #wargames

Another day, another challenge…

In today’s challenge we’re going to solve level 8 from the Natas wargame.

Let’s begin.

Going to the following link, and entering the username “natas8” and password “DBfUBfqQG69KvJvJ1iAbMoIpwSNQ9bWe” we get the following:

Natas8_WarGame_1

Natas8_WarGame_2

OK, we see a page that is asking for an input secret. Clicking the view sourcecode link we see:

Natas8_WarGame_4

Looking at the screen, there’s PHP code with an encoded secret variable that seems to be in hexadecimal. There’s also a function titled “encodeSecret” that does the following steps:

  1. Change the binary to hex (bin2hex)
  2. Reversing the string (strrev)
  3. Base64 encoding (base64_encode)

From there the code is checking to see if our input secret equals the encoded secret. If it does then we get the code for level 9, otherwise we need to try again.

So, how are we going to solve this?

Going to Google and looking for a PHP interpreter, we’re presented with the following link.

From there, We’re going to do the reverse the steps of above. Our new steps are:

  1. Convert the hex to binary (hex2bin)
  2. Reverse the string (strrev)
  3. Base64 decode (imap_base64)

Below is the screenshot that depicts the above steps.

Natas8_WarGame_5

Doing the steps, we are presented with the decoded secret which is “oubWYf2kBq”

Going back to the level 8 page, and entering our decoded secret we get the following:

Natas8_WarGame_6

We found the flag!

OverTheWire: Natas Level 7 – #appsec #webapp #websecurity #wargames

Another day, another challenge…

In today’s blog post we will solve level 7 from the Natas wargame challenge.

Let’s begin.

Going to the following link, and entering username “natas7” and password “7z3hEENjQtflzgnT29q7wAvMNfZdh0i9” we see the following:

Natas7_WarGame_1

Natas7_WarGame_2

Hmm… we see a Home and About links. Let’s click the links and see what happens.

Natas7_WarGame_3

Natas7_WarGame_4

After clicking the links we see there’s not much that’s showing on the screen.

Let’s view the source and see if there are any hints there.

Doing a right click, view page source we see:

Natas7_WarGame_5

Hmm… we see a comment that says, “password for webuser natas8 is in /etc/natas_webpass/natas8”

How can we use this information?

Looking at the above screenshots of Home and About – we notice that at the end of the URL it’s referencing a page. For instance for the home page it’s “page=Home” and for About it’s “page=About”. Let’s try to change the page name to the hint that was provided to us.

Changing the URL to: http://natas7.natas.labs.overthewire.org/index.php?page=/etc/natas_webpass/natas8, we see…

Natas7_WarGame_6

the flag!

OverTheWire: Natas Level 6 – #appsec #webapp #websecurity #wargames

Another day, another challenge…

In today’s blog post we’re going t solve level 6 in the Natas wargame.

Let’s begin.

Going to the following link and entering the username of “natas6” and password of “iX6IOfmpN7AYOQGPwtn3fXpbaJVJcHfq” we see the following:

Natas6_WarGame_2

Natas6_WarGame_3

Doing a right click, view source we see:

Natas6_WarGame_4

Hmm… there’s not much in here, except there’s a view sourcecode. Let’s see what this source code will yield us…

Natas6_WarGame_5

Looking at the middle of the page, we see that there’s php code (code between <?…?>), we notice that there’s an include/secret.inc. Let’s see if we can access this file and see what’s inside the file.

Changing the URL to “natas6.natas.labs.overthewire.org/includes/secret.inc” we see:

Natas6_WarGame_6

… a blank page. Let’s do a right click, view page source to see if there are nuggets hidden beneath the surface.

Doing a right click, view page source we see the following:

Natas6_WarGame_7

Hmm… looks like we find the secret.

Let’s enter this into the input box and see if this unlocks the level.

Entering the secret above into the input box we get:

Natas6_WarGame_8

Natas6_WarGame_9

We found the flag!

OverTheWire: Natas Level 5 – #appsec #webapp #websecurity #wargames

Another day, another challenge…

In today’s blog post, we’re going to solve level 5 from the Natas wargame challenge.

Let’s begin.

Going to the following link and entering username of “natas5” and password of “iX6IOfmpN7AYOQGPwtn3fXpbaJVJcHfq” we see the following:

Natas5_WarGame_1

After pressing “OK” we see:

Natas5_WarGame_5

Hmm… we see that we’re not logged in and access is disallowed.

Using Tamper Data, let’s see if the request headers show us a way to bypass the login feature.

Opening the Tamper Data application and refreshing the website we see:

Natas5_WarGame_2

Hmm… we see inside the Cookie that there is a loggedin that is currently set to zero. What if we change it to 1?

Changing the loggedin feature to 1 and pressing Enter we see:

Natas5_WarGame_4

Natas5_WarGame_3

We received the flag!

OverTheWire: Natas Level 4 – #appsec #webapp #websecurity #wargames

Another day, another challenge…

Today’s blog post we’re going to solve level 4 from the Natas wargame.

Let’s begin.

Going to the following link we see:

Natas4_WarGame_1

After entering the username of “natas4” and password of “Z9tkRkWmpt9Qr7XrR5jWRkgOU901swEZ” we get the following:

Natas4_WarGame_2

Hmm… we’re not allowed access because we’re coming from an invalid URL. Let’s see if we can change that.

In a previous blog, I explained how to user Tamper Data. Tamper Data allows you to modify HTTP requests and responses to see if the web page will behave differently.

We’re going to use Tamper Data for this challenge.

 

Starting Tamper Data, and going to the level 4 we see:

Natas4_WarGame_4

We see that the referrer shows natas4, what happens when we change it to natas5?

 

Changing the referrer to natas5, and clicking OK we see:

Natas4_WarGame_5

Natas4_WarGame_6

We found the flag!