The malware was analyzed by experts from security company IntelCrawler, and they have discovered that the cryptographic toolkit used to encrypt the victims' files has flaws that can be exploited to create effective "skeleton keys" to decrypt them.
According to IntelCrawler CEO Andrey Komarov, they have already managed to develop these keys, and they can decrypt any infected client.
The ransomware - dubbed Locker - currently has an extremely low detection rate. Users get infected via drive-by downloads and by receiving and opening executables disguised as mp3 files.
Once the malware is on the target computer, it proceeds to encrypt files one by one, leaving the encrypted versions behind and deleting the non-encrypted ones.
It also places a text file containing instructions on what to do (pay up $150 to receive the key) and how to contact the criminals (via throwaway phone numbers and emails) in each computer directory.
After paying, the victims contact the criminals and give them their computer's hostname and the identifying code witten in the text file.
"It seems to be the hackers just compare the list of infected IP addresses of the users together with their hostnames," Komarov told The Register.