Posts Tagged "vulnerability"

Yahoo Full Application Source Code Disclosure Vulnerability

Yahoo Full Application Source Code Disclosure Vulnerability


Hello Friends,

Today I will be talking about a “Full Application Source Code Disclosure” Vulnerability in one of Yahoo domains.

Domain name:

Vulnerability Type: SVN Repository Disclosure Vulnerability

What is SVN ?:

SVN is a system to keep track of changes to project files. It’s usually used for any kind of project, being PHP or not, and many concurrent users to allow them to change files without overwriting each others’ changes.

Quoted from: “”

In the Exploitation scenario, SVN Directory got a file named as “entries”

This file contains the files names and directories names of the project/application.

.e.g “

As it’s clear from the above description, this SVN directory should be located only out side the web directory.

But what if that directory is located in the web directory? let’s explain the Yahoo vulnerability to understand it.

While Searching in the above mentioned domain name I found below directory on the web directory, and I’ve added “Entries” to it:

Screenshot from 2014-07-11 15:24:45


Now I can see each file and directory of the web application, so What?!

  • If the Yahoo server admin has compressed some files in .zip file, in normal scenario i will not be able to see it! but now I can see and download it 🙂
  • If the developer made a copy of the files such as config.php.bak, in normal scenario I wont see it, but now I can!
  • If the admin panel is hidden and I cant find it with any directory bruteforcing tool, Now I can easiely find it!

And many other Exploitation scenarios that could be conducted if the SVN directory is located on the web directory.

While searching the directories fetched from the Entries file, I found some directories that contain a HTML files named with the same name as the PHP files, and guess what? It has the source code of the PHP files!


Now that I knew it, I can’t visit every directory and then visit every HTML file inside the directory to see the source code!

So, I’ve wrote a Python POC file that will visit every dir and then fetch every page inside that directory to get a good POC.

The above vulnerability also helped me to gain UnAuthorized Admin access to a dir in that domain name:


I’ve reported to Yahoo both vulnerabilities:

  • Source Code Disclosure
  • Unauthorized Admin Access

Yahoo has decided to gather both vulnz in one report, and has rewarded me with, take a guess?

Yahoo has rewarded me a 250$ for this report! ya it’s 250$ you see it right 😀

This is one of the consequences of Yahoo minimized the minimum reward to be 50$!

However, Thanks Yahoo team for releasing a fast fix for this vulnerability.

Follow me on Twitter: Unvalidated Redirection Vulnerability. Unvalidated Redirection Vulnerability.


Would you trust a link from your security vendor? Absolutely Yes! But imagine your security vendor is asking you to download a malware!

During my researches on I found “Unvalidated Redirection Vulnerability ” that could be used by attackers to trick users into visitng Malicious web-sites!

To demonstrate the impact of such vulnerabilities I made a video to simulate a black-hat method to use this vulnerability to spread a Malware.

Video POC:

The consequences of unfixing of such vulnerability are critical
  • Wide infection – since the redirection is coming from a trusted source especially if the attacker registered a domain name similar to
  • Very bad reputation for Kaspersky company.
  • Your most trusted resource “Your Antivirus” will be your worst enemy! Would you trust anything else!
And many other consequences. The vulnerability was reported to Kaspersky web-team and is now fixed.