On April 25th, the operators behind the Shade ransomware (also known as Troldesh) created a GitHub repository full of decryption keys. About a day later, README files were added explaining that the group had already ceased operations at the end of 2019 and were hoping for someone to create user-friendly decryption tools using the released keys. The repository contains over 750,000 keys from individual infections and a folder with five “master” keys that can aid researchers in creating a more universal decryptor. The farewell message left by the operators stated, “We are the team which created a trojan-encryptor mostly known as Shade, Troldesh or Encoder.858. In fact, we stopped its distribution in the end of 2019. Now we made a decision to put the last point in this story and to publish all the decryption keys we have (over 750 thousands at all). We are also publishing our decryption soft; we also hope that, having the keys, antivirus companies will issue their own more user-friendly decryption tools. All other data related to our activity (including the source codes of the trojan) was irrevocably destroyed. We apologize to all the victims of the trojan and hope that the keys we published will help them to recover their data.”
Although the group released instructions on how to use the keys and the decryption software developed by the ransomware authors to recover data, Binary Defense recommends waiting for researchers to release their own tools that are more trustworthy. Any organizations previously infected by Shade may also choose to download the GitHub repository to have their own copy of the decryption keys while waiting for tools to become available. This recommendation may not be heard as often, but scenarios like this are one of the reasons why researchers recommend creating backups of encrypted data after an infection. It may be possible to decrypt files long after they were affected by ransomware, but that is only possible if copies of the encrypted files are still available. Flaws in encryption implementations are sometimes found as well.