Another one of the hacker's videos shows how he performs the attacks using a Microsoft connection protocol, RDP, or Remote Desktop Protocol.
RDP was developed by Microsoft to let administrators access other remote computers. Since many POS terminals are Windows-based, Visa warned merchants in last August that RDP log-ons should be disabled.
Postings on the underground forums seen by IDG News Service show that cybercriminals buy and sell access to point-of-sale terminals and other systems that have RDP enabled.
Intruders often try the default login and password for terminals, and if that doesn't work, attempt brute-force attacks, which try many combinations of credentials. Vulnerable IP addresses can be probed from anywhere in the world for weaknesses.
The hacker who posted on YouTube showed he had access to sales orders of the events company between 2009 through 2012. Various video frames show customer names, addresses, email addresses, credit card numbers and expiration dates.
An analysis by IntelCrawler shows a thriving interest in RDP hacking. Its analysts gather data from password-protected forums used by cybercriminals, which gives insight into the latest trends.
On Nov. 27, the day that Target believes hackers began collecting payment card details, a posting on a Russian-language forum showed a buyer offering $100 for access to a hacked RDP POS terminal.
The buyer was interested in Track 1 and Track 2 data, which is information coded on the back of a payment card's magnetic stripe. Track 1 data contains a card number, the holder's name expiration date, while Track 2 data contains the card number and expiration date.
Sign up for CIO Asia eNewsletters.