Emmanouil Perselis
Emmanouil Perselis Ethical Hacker, Security and Privacy Consultant, Programming Teacher and Author.

My Cyber War Story: Black Box Penetration Test Part 2

My Cyber War Story: Black Box Penetration Test Part 2

If you haven’t read it yet, you can find part 1 of this story here.

Cracking the domain passwords

There were more credentials of C-level executives to be found. Since I already had access to the Domain Controller, I decided to crack the passwords in the domain. To achieve that, I had to create a shadow copy of the C drive on the Domain Controller as copying ntds.dit (Active Directory database) isn’t (easily) possible without it.

Creation of a volume shadow copy using
VSSAdmin

Copying Ntds.dit file from a volume shadow
copy

The system key was also needed to retrieve the hashes, so it had to be copied too.

Extracting the SYSTEM file through the
registry

Extracting the System file from the volume shadow
copy

After storing the hashes locally, cracking them was easy since they are hashed by a weak format, LM. All of the above were done of course with the help of John the Ripper (cracking tool).

07 - john

Setting up a Phishing Page

Although cracking the domain passwords of all C level executives was successful, one of them did not reuse the same password on the applications linked to financial transactions. So I had to devise another plan. This made me use the almighty spear-phishing attack that has never failed me before.

To make the attack credible, I copied an internal web page with HTTrack and changed the back end to log the entered credentials.

Since I had access to the Domain Controller, I added a credible DNS A record to point to my phishing page.

Add Host A Record in Windows DNS
Server

Phishing

The phishing page was up and running. As a final step, I needed to send the phishing link with a good story behind it. To make the story credible, the communication had to be done from a legitimate account (or at least what looked as a legitimate account). The company mail servers allowed open relay. This allowed me to send a mail on behalf of a “system administrator” asking the CFO to test the “new file sharing system”.

To make the page seem legitimate, I had also requested a HTTPS certificate from Let’s Encrypt so that the URL had the “secure lock” activated.

The CFO gladly complied to the request of the “system administrator”. This way, I was able to collect the last set of credentials needed!

Aftermath

After successfully reaching the black box penetration test goals in only 2 days, the client requested me to conduct a white box test next. Not long after the tests, the client performed a mass-update of their systems and migrated to the cloud. In short, they dodged the bullet (or rather the homing missile) as they realized the exploitation path I followed was not complex and could have been performed by even less experienced hackers.

Disclaimer

  • All screenshots used in this article are mere representations and not the actual screenshots from the penetration test.
  • This story is my professional experience based on a client’s request. It is illegal to penetrate a system without agreement of the owner