According to a post on the market's forum, a hacker figured out a way to create fake orders which he immediately cancelled using their seller account, creating refunded funds out of thin air, which he immediately withdrew.

Using this method, the hacker able to gain 13 Bitcoins (BTC), which is the equivalent of over $752,000, according to Check Point Research.

"The vaccine marketplace on the Dark Net that offered those products and services is now down, due to a hack," the researchers noted.

However, this has not stopped the sale of Covid-19 related "goods" on the Dark Web.

Since the marketplace went down, a hacking forum was staged on the same web address offering a variety of advertisements, with Covid-19 vaccines and vaccination documents included, and all at great discounts for promotion purposes.

Cyber security researchers earlier revealed that forged Covid-19 test results and fake vaccine certificates are being offered on the Dark Web and various hacking forums from as low as $25 (Rs 1,800) to $250 (about Rs 18,000), for people seeking to board flights, cross borders, attend events or start new jobs.

To access fake 'vaccine passport' certificates, those interested just need to send their details and the money, and the seller on Dark Web will email back the fake documents for $250.

Fake negative Covid-19 test results are on sale from various sellers from just $25, according to Check Point Research.

The researchers found that the dark net advertisements for Covid-19 vaccines have increased by over 300 per cent in the past three months.

The Covid vaccine sellers are majorly based in the US and European countries including Spain, Germany, France and Russia.

"The vaccines advertised include Oxford-AstraZeneca (at $500), Johnson & Johnson ($600), the Russian Sputnik vaccine ($600) and the Chinese SINOPHARM vaccine," the researchers informed.