We know the Oscars as a celebration of the best in big screen entertainment but for pirates it's the perfect opportunity to strike as every year movies submitted for selection are leaked online and downloaded in their millions.

It happens every year. Around December 'screeners' – clean DVD copies of cinema films – of the biggest movies of the year, including those still yet unreleased, are submitted to voters for inclusion for the upcoming Academy Awards. It's known as 'Oscar Screener Season' for pirates where these full HD versions, which are seen as premium pickings, are sent to authorised individuals and somehow find their way flooding onto torrent sites.

As expected, this year is no different. Several movies including The Hateful Eight, Leonardo DiCaprio's The Revenent, and Steve Jobs were leaked online and saw over a million individual downloads in just 24 hours. Digital Trends reports that according to data released by copyright intellence company Excipio The Revenant was in highest demand with over 739,580 unique IP addresses downloading the film in a 24-hour period. The Hateful Eight and Creed were also downloaded by 569,153 and 499,082 IP addresses.

Other films leaked by pirates in the past few days include Joy, Legend, In the Heart of the Sea, Carol, Room and Brooklyn.

This will be extremely damaging for film makers' revenues and will come as a triple-blow for Quentin Tarantino, who has already seen his latest instalment, The Hateful Eight, replaced in some cinemas by extra screenings of Star Wars: The Force Awakens, after the script of the movie was leaked online earlier in the year.

It also serves as a huge wake-up call to the Oscars screening process as piracy groups such as Hive-CM8, who have taken credit for the leaks, once again expose huge flaws in the screening process. "DVDScreener 1 of 40. Will do them all one after each other, started with the hottest title of this year, the rest will follow," Hive-CM8 posted.

How internet pirates get hold of unreleased movies

Exactly how they got their hands on the movies isn't entirely known but hacking into emails, which often contain a special code to access the movies on iTunes, and file transfer services to intercept the file isn't out the realms of possibility. Also, surprisingly, members of the Academy themselves have been found to leak them. In 2011, Wes DeSoto, a member of the Screen Actors Guild, uploaded his copy of The King's Speech to The Pirate Bay. This led authorities to discover he had uploaded four other movies over the course of a week.

Usually, pirated screeners will have watermarks or text stamped across the top stating this fact, however it is hardly obtrusive enough to put people off and this year some films didn't even feature them.

Movie studios have previously employed a forensic watermark digitally embedded into the screeners, which has worked to trace and prosecute sources that have illegally uploaded movies online, but pirates are using newer technology to effectively scrub this away.

It's a battle the movie studios will continue to face on an annual basis until a more secure system is put into effect. The money they lose from box office sales as a result of illegal downloads combined would easily cover the cost to develop ways to keep movies out of the hands of pirates.