Hello again! Welcome to another write-up. Today, we are tackling the mega CTF There Have 10 challenge. Let's solve it together!
Challenge Details:
CTF Name: Mega CTF
Topic: Web Exploitation & Cryptography
Level: Beginner
Flag Format: IHC_CTF{}
CTF Link: https://t.me/ctf_invisiblehc/24
Description:
The website plays a very important role for the identity of an organization. Different types of services are offered on the website. But a wrong one is very harmful for the site. So website analysis is very important to stay away from these bugs.
Visit the site: https://site.invisiblehc.com/ctf/13/
Analysis this site & find 10 flag.
Solution:
Flag 1:
Visiting the website, we right click and choose to view source code, getting the first third of the flag, included as a html comment:
<!-- Flag 1 Part 1: IHC_CTF{1N5 -->
The second part of the flag comes from the referenced CSS file styles.css:
/* Flag 1 Part 2: P3C7_M3_ */
The last part comes from the Javascript scipt script.js:
// Flag 1 Part 3: whckbe}
Here combining the 3 parts gives the flag:
Flag No 1: IHC_CTF{1N5P3C7_M3_whckbe}
Flag 2:
There is nothing visible. If we highlight the page, we’ll see that the flag becomes visible because it is the same color as the background.
Flag No 2: IHC_CTF{H1DD3N_73X7_hdydbt}
Flag 3:
I suspected that it had to do with robots.txt,
So I added 'robots.txt' to the end of the site URL.
This brought up a robots.txt file with the following content:
User-agent: Googlebot
Disallow: /2023_IHC.html
Allow: /flag.html
We found two paths in the robot.txt file. When we pasted the /2023_IHC.html path at the end of the URL,
we were directed to a webpage and found the flag.
Flag No 3: IHC_CTF{R0B075_F1L3_15_1MP0R74N7_keabwj}
Flag 4:
On the webpage, there's an HTML image with the filename "invisible.jpg" as the picture source. The image alt attribute description contains a hidden flag.
Flag No 4: IHC_CTF{1M4G3_71713_askfjo}
Flag 5:
When we checked the cookies of the site, we found a cookie named "flag5" with an encrypted value.
After decrypting the encrypted value Using CyberChef.we discovered the flag5:
Flag No 5:
IHC_CTF{C00K13_15_4W350M3_daksjf}
Flag 6:
We found two paths in the robot.txt file. Then, I checked the /flag.html file,
we were directed to a webpage, but there was nothing visible on the page. However, when we highlighted the page, we found a cipher text.
After decrypting the ciphertext using CyberChef, we obtained the flag :
Flag No 6: IHC_CTF{50M3_CRYP70_alsjfs}
Flag 7 :
We downloaded Flag.txt after open the txt file we got this text:
Opps. I couldn't give you any flags.
But you can take the flag from me.
I suspected there might be some hidden characters, so I decoded it using this website:
and found the flag. Flag No 7:
IHC_CTF{73573G4N0GR4PHY_kjerxn}
Flag 8:
To find the flag, we need the IHC Browser. I can convince the website that I'm using the IHC Browser by changing the user-agent string. To do this, I'll use curl since it allows easy control over headers. Just run the following command.
curl --user-agent "IHC Browser" "https://site.invisiblehc.com/ctf/13/"
By exploring the source code, we'll find the hidden flag.
Flag 8: IHC_CTF{BR0W53R_N4M3_C4N_B3_CH4NG3D_ksdjfh}
By setting the referer header appropriately, we can access the hidden flag.
By using the curl command with a properly set referer, we can access the hidden flag
curl -e "https://invisiblehc.com/" https://site.invisiblehc.com/ctf/13/
By exploring the source code, we'll find the hidden flag.Flag 9: IHC_CTF{R3F3R3R_4150_B3_CH4NG3D_sdkfkv}
Flag 10:
To find the flag, we needed to go back before 2020.
While checking the website's cookies, we discovered a new cookie named "time."
We realized that changing the time value to the past would help us.
to convert the new timestamp, which we then replaced with the current time value. Finally, we found the flag:
Flag 10: IHC_CTF{G0_7H3_P457_sdkfjh}.
Mega CTF completed!
Join Our CTF Channel:
