The Polish branch of the Anonymous hacker collective has hacked the servers of the World Anti-Doping Agency (WADA) and Court of Arbitration for Sport (TAS / also CAS).

The group has already dumped online the data taken from the TAS server, along with a video showing one of the members hacking the TAS web servers.

The leaked data contains a basic site database dump and no other information on court cases or sensitive personnel information.

No WADA data dump yet, but WADA admits the incident

The group has not yet released the WADA data breach, but WADA spokesperson Maggie Durand acknowledged the data breach to AP reporters yesterday at the Rio Olympics.

Durand also said the group did not compromise WADA's database that holds information on athletes drug test results.

Five days ago, the Anonymous hacker collective called for a widespread hacking campaign against the Brazilian government and the International Olympic Committee during the Rio Olympics.

Previous attacks only included basic DDoS attacks that took out the websites of various Brazil sporting federations.

Background information

The attacks on WADA and TAS are unique because they also include data dumps, which involve more effort and planning than a simple DDoS attack. The data breaches were announced from a Twitter account that was dormant for over four years.

WADA and TAS were previously involved in an investigation that banned Russian athletes from the Rio Olympics due to the discovery of a state-sponsored doping program.

Just before the Olympics, ICO cleared 278 of the 389 banned Russian athletes from participating in the Olympic Games.

The Dutch Safety Board also reported cyber-attacks while it was investigating the crash of Malaysia Airlines Flight 17 (MH17) in Ukraine after it was hit by a Russian-made anti-aircraft rocket.

Before dumping the TAS data, the hackers tweeted offensive messages against Pravyy Sector, a group posing as Ukrainian nationalists that hacked several Polish government agencies and even tried to extort $50,000 from the Polish government.

Softpedia has reached out to Anonymous Poland for comments on the motives of their attack.

UPDATE: One of our readers has pointed out that a Polish weightlifting champion has been disqualified for doping, which may be the most likely reason behind the attack. Softpedia is still waiting for Anonymous Poland to issue an official reply/statement on this attack.