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InfoSec Institute CTF #13

June 10, 2017March 3, 2021 thefluffy007

Another day, another challenge…

Today’s challenge is from the InfoSec Institute.

Going to the following link, we see the following:

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

So from the hint we’re looking for a back-up file.

Since this is on a Linux box, let’s see what what the naming conventions are for backup files.

Let’s see if there’s a backup folder.

That led us to a dead-end.

Let’s try adding .old at the end of the file.

Adding the “.old” at the end of the URL and pressing enter we get the following:

Hmm… this looks like another file. Let’s open it.

Opening the file in a text editor we get the following:

Looking at the file we see the the first paragraph, which matches our first screenshot.

Next we see commented out code, that is asking us to download a mysterious file, “iamadecoy”.

Let’s navigate to this file and see what we find.

After the file downloads, we try to open it.

Hmm… that’s weird when clicking on the file a prompt is shown asking what type of file this is.

Since we don’t know what type of file it is, let’s go to this site here, to find out.

After uploading our file we determine that is a pcap file.

We’re going to need Wireshark for this one…
Opening Wireshark, and opening our file we’re presented with the following:

The beginning of the file is DNS queries that are rejected we can ignore that.

Searching through the file we notice some HTTP requests that are getting files, in particular – HoneyPy.png

Going to packet 633

We can reconstruct this exchange.

Going to File –> Export Objects –> HTTP

We get the following:

Our file is highlighted in the above screenshot, so let’s click Save.

Opening the file we get our flag!

Lessons learned:

Use the hints that are provided! We knew that the file we were looking for was a backup. After playing around with the filenames we discovered that the file we were looking for ended in an “.old”. Once we opened the file we noticed there was another file “imadecoy”. After downloading that file and trying to open it our operating system was confused on the file type. Uploading our file to the above link we determined that the file had a pcap (packet capture) extension, and we would need to use Wireshark.

Opening Wireshark, we determined that the file we needed was inside of an HTTP packet. Reconstructing the packet we were able to download the file we needed. After opening that file we received our flag. This challenge was a multi-step process. It’s very important to pay attention to detail.

capture the flag, hacking, web application security

InfoSec Institute Challenge #12

June 8, 2017March 3, 2021 thefluffy007

Another day, another challenge.

Today’s challenge is coming from the InfoSec Institute.

Going to the following link we see the following:

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

We noticed there’s an extra CSS (Cascading Style Sheets). Let’s see what’s in this file.

Going to the file we see the following:

Hmm… this looks interesting. Knowing a thing or two about CSS, the colors are represented in hex (hexadecimal, base 16) form. More can be found here.

I’m thinking this is the actual flag, but it’s just encoded.

Using out knowledge from other challenges, let’s try base64 decoding, since it has worked before.

Going to the link here, and typing in the encoding we get the following:

Our decoding wasn’t successful. This encoding is not base64.

Going back to the challenge, we know that CSS uses hexadecimal to represent colors.

Maybe the encoding is in hexadecimal form.

Going to Google and typing in “converting hexadecimal to text” we get the following link.

Putting our encoding in the text box and changing the decoding to “hexadecimal to text” we get the following:

We found the flag!

Lessons learned:

Attention to detail! We noticed that there was another file when we did the right click, view page source. Going to that page we noticed that there was encoding. We first tried base64 which did not work. Going back to the drawboard on how CSS works, we know the colors are represented in hexadecimal. Doing a Google search of hexadecimal to text we were able to find the flag.

capture the flag, hacking, web application security

InfoSec Institute CTF Challenge #11

June 7, 2017March 3, 2021 thefluffy007

Another day, another challenge.

Today’s challenge is from the InfoSec Institute CTF.

Going to the following LINK we see:

Doing our favorite trick of right click, view page source we see the following:

We see an image of “php-logo-virus.jpg” hmm… what happens when we click this file?

We see the following:

Looks like a simple file… looks can be deceiving.

Just going from the title of the file, there’s something in this file that we’re not seeing.

Let’s use our trick from the last challenge of using strings to see if this is a true file.

Using the strings command inside our cygwin terminal we see the following:

Hmm… we see the beginning part of the flag. The last looks like encoding.

Let’s try to decode it.

One of the encoding we’ve seen in the challenges have been base64 encoding, so let’s use that to see if we can decode the message.

Going to this link, and typing in the encoding we see the following:

We’re presented with a link. Going to that link we see the following:

Combining the this with the beginning of the flag, we get infosec_flagis_powerslide!

Lessons learned:

Most of these challenges build on top of each. We still used our tried and true right click, view page source to see if there are any nuggets that were not shown on the page. We noticed there was a file. Looking at the name, we determined that there was more than what met the eye. Using another command we learned – strings we were able to see that the flag was embedded in picture, but it was encoded. Using previous knowledge, we noticed that previous challenges used base64 encoding so we used that (base64) to see if we can decode the text. After decoding we went to the link and used the image to complete the flag.

capture the flag, hacking, web application security

InfoSec Institute CTF Challenge #10

May 30, 2017March 3, 2021 thefluffy007

Another day, another challenge…

Today’s challenge will be on Challenge #10 from the InfoSec Institute CTF program.

Going to the following link we’re provided with the following page.

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

There’s a listen button. If we click on that button we’re presented with a flag.nav file. Maybe the flag is in there? Let’s see.

Opening the file we noticed that the file is one second, and we can’t hear the audio.

Going back to the original page and doing a right click save link as… allows us to save the audio.

There’s a GREAT application called Audacity that can be used to change the pitch and speed of an audio file.

Going here you will be presented with the Audacity webpage.

Downloading Audacity and opening the flag.wav file we see the following:

Playing the file it’s still inaudible.

Like I wrote above, with Audacity you can change the speed of sound of the audio without changing the pitch.

Going to the toolbar and selecting effects there’s a “changing speed” option. Clicking this option we can specify different speeds. After playing with the different speeds (.75x, .50x) and making it .22x and playing the audio again we can hear the flag.

The flag is:

infosecflag_is_sound.

We found the flag!

Lessons learned:

Our trick of doing the right click view source helped a little bit. When doing this we noticed that there is a file we needed to download. After downloading the file and playing the audio it was inaudible. Going to Google we downloaded an application that aided us to in interpreting the audio. After adjusting the speed we were able to get the flag.

capture the flag, hacking, web application security

InfoSec Institute CTF Challenge #9

May 28, 2017March 3, 2021 thefluffy007

Another day, another challenge…

Today’s challenge will be #9 from the InfoSec Institute CTF.

Going HERE we’re presented with the following:

Doing our handy source of right clicking viewing the page source we see the following:

We see that there’s a form that takes a username and password.

Using the hint from the challenge we know we’re looking for a CISCO IDS login.

Going to Google and typing in “common username and password for CISCO IDS” we’re presented with the following link.

Searching the link for username and passwords we see the following:

Going back to our login screen and entering the first username of “netangr” and password “attack” we get the following:

The username and password didn’t work 🙁

Let’s try the second username of “root” and password of “attack”.

We’re presented with the flag… but it looks like gibberish.

Inspecting the flag closely we noticed that it is backwards.

The flag is infosec_flagis_defaultpass!

Lesson learned:

Our handy trick of looking at the page source did not work. It revealed that challenge was using a form. Looking at the webpage we noticed that there is a hint – CISCO IDS. Using this information we know that most devices have a default username and password. Going to Google we found the webpage that listed a default username and password. The first username did not work, second one did. From that we found the flag even though to the naked eye one might ignore it. Looking at the flag again we noticed that the flag was written backwards. After putting the flag in the correct order we were able to see it.

capture the flag, hacking, web application security

InfoSec Institute CTF Challenge #6

May 24, 2017March 3, 2021 thefluffy007

Another day,. another challenge…

Today’s challenge will be on the InfoSec Institute CTF Challenge #6.

See scenario below:

Doing a page source we see the following:

We see that there’s a pcap file if we select yes.

Opening Wireshark (which can be downloaded HERE)

We see the following:

Wireshark is a program that is used to analyze network traffic. Most of the traffic in this file can be ignored as there is a lot of noise that is being displayed.

Looking at the first packet (UDP) we see the following:

We noticed there are a bunch of letters… possibly this is hexadecimal encoding?

Going to Google and searching for “hexadecimal decoding” we see the following link as the first result.

Clicking on the link and typing in the encoding we get the following:

We found the flag!

Lessons learned:

Download Wireshark!
Inspect the packets, and pay attention to those that stand out. Usually the suspicious packets hold clues!
These clues won’t give us the pot of gold on the first try. Most of the data will be obscured. So we will need to encode or decode the data
Once we encode or decode usually the data will be there!

FYI – thenewboston on Youtube has a good beginner tutorial on Wireshark. Which can be found HERE.

capture the flag, hacking, web application security

InfoSec Institute CTF Challenge #5

May 7, 2017March 3, 2021 thefluffy007

Another day, another challenge…

Today’s challenge is #5 from the InfoSec Institute CTF Challenge.

Clicking on the following link we’re presented with the following:

After clicking on the checkbox to prevent the page from displaying additional dialogs, and adding “view-source:” to the URL box we see the following:

When viewing the page source further the reason we were getting multiple alert boxes was that it was inside of an infinite for loop. Read more about for loops HERE.

Looking inside the for loop we see that there is a image field titled “aliens”. Clicking on the file we see the following:

At first when I read the meme I was at a loss, as I have never seen or heard this quote before. After doing some digging online, it hit me. What if there’s another secret meaning to this message?

How does one add a secret inside of an image? Steganography.

Saving the image, and doing a quick Google search of Steganography decoder online we’re presented with this site.

Uploading our file, and pressing decode we get the following:

Binary. OK… this doesn’t seem helpful, or is it?

Doing another Google search to decode binary to ASCII we’re presented with this link.

Entering our binary code, we get the following:

We found the flag!

Lessons learned:

Don’t be deterred by the multiple alert boxes!
Using our trick of adding “view-source:” to the beginning of the URL
Reviewing the page source we noticed a file
Opening file we noticed it was a meme
Researching what meme meant
After finding meaning using tools to extract data that we needed
Not being deterred that the extracted data was not in our preferred format (words not binary)
Used Google to research how we could get extracted data into preferred format (words not binary)
Finally, finding our flag

capture the flag, hacking, web application security

InfoSec Institute CTF Challenge 3

May 6, 2017March 3, 2021 thefluffy007

Another day, another challenge…

Today’s challenge will be #3 from the InfoSec Institute.

Going to the following link we’re presented with the following:

Looking at the screen we’re presented with a qr code.

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

Doing a quick Google search of “QR code decoder” we go to the following site.

Entering the proper information and uploading our file we see the following:

Doing a Google search of our output the code is actually Morse code!

Another Google search to decode the code gives us the following site.

Putting our code inside of the decoder we get the following:

We found the flag!!!

Lesson learned:

Right click, view page source saves the day again. By doing this we found that there is a qrcode being displayed on the page. Doing a quick Google search we found a QR code decoder that gave us morse code. Another Google search yielded the flag.

When in doubt view page source and Google searches!

capture the flag, hacking, web application security

InfoSec Institute CTF Challenge #4

May 6, 2017March 3, 2021 thefluffy007

Another day, another challenge…

Today’s challenge is #4 from the InfoSec Institute CTF challenge.

Going to the following link we see the following:

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

Looking at the page we see the following hint – “Hypertext Transmission Protocol”

Pressing F12 to view the developer tools and going to the “Network” tab we see the following:

Inside the set-cookie we see “fusrodah=vasbfrp_syntvf_jrybirpbbxvrf”. This is interesting…

Doing a quick Google search and putting in the second half of our value we get the following link for ROT-13.

ROT-13 is a rotation 13 cipher. This cipher rotates each character by 13 characters.

Using the following site, and putting in our value we get:

We retrieved the flag.

Lessons learned:

Use the hints provided. We our trust right click, view page source, but that didn’t help us. Going back to the page we noticed that the hint was HTTP. Using the development tools inside Chrome and going to the network tab we saw the files retrieved when accessing the site.

Clicking on the page, and viewing the headers we noticed that the cookie was being set. Using this information inside Google we were able to decode the message.

capture the flag, hacking, web application security

InfoSec Institute Capture The Flag #2

May 5, 2017March 3, 2021 thefluffy007

Another day, another challenge.

Today’s challenge will be on the second ctf challenge from the InfoSec Institute.

Below is the screen listed HERE when accessing the link:

Doing a right click view page source and scrolling down we see the following:

We see a img src that points to a leveltwo.jpeg. Clicking the file we get the following:

Going to the space bar and add the “view-source:” to the beginning of the address bar we get the following:

We got the flag!

Lesson learned:

Once again do the right click page source. In the beginning it didn’t reveal too much except that there was an image. Clicking on said image we’re brought to a page with a non-rendered image. Viewing the source of that image we see the flag. This is security through obscurity which never works.