Allan Liska, a ransomware expert from security firm Recorded Future, told iTWire that the ransomware in question appeared to be BitPaymer.
Liska, who is also a solutions architect, said: "Based on the content of the ransom note, the PGA Championship appears to have been hit by the BitPaymer ransomware, which is the same ransomware that infected the Matanuska-Susitna (Mat-Su) borough in Alaska and several hospitals in Scotland last year."
The attack on Matanuska-Susitna was so severe that the staff in the borough were reduced to using typewriters, with IT director Eric Wyatt saying recovery would easily take three weeks.
"Unlike Locky, which was primarily delivered via phishing attacks, BitPaymer is generally delivered as part of an exploitation campaign, most often initiated through internet-facing RDP servers.
"The Dridex team will either exploit unpatched RDP systems or brute force common username/password combinations."
According to a report in Golfweek, the attack prevented officials from accessing files related to the PGA Championship and the forthcoming Ryder Cup in France.
The ransomware made its presence known on Tuesday when staff who tried to work on files were greeted by the message: "Your network has been penetrated. All files on each host in the network have been encrypted with a strong algorythm [sic].”
The message warned that any attempt to break the encryption would make it impossible to recover certain files. A bitcoin wallet number was provided, but no specific amount was demanded.
The files that were inaccessible included promotional banners and logos used in both digital and print media, and development work on logos for future PGA championships, some of which has been worked on for more than a year.
The attackers appeared to have launched the attack to make money. “We exclusively have decryption software for your situation,” they wrote. “No decryption software is available in the public.”
While the PGA of America has tried to tackle the problem, they had not regained control of their files as of Wednesday, Golfweek said.
It added that a spokesman had said there would be no comment on the situation as it was yet to be sorted.