BTCWare, also known as CrptXXX and CryptoByte, targets Windows OS and is distributed manually via Remote Desktop Protocol (RDP) compromise.
Extensions appended to encrypted file names:
.btcware, .cryptobyte, .cryptowin, .[email@example.com].theva, .onyon, .xfile, .master, .[<bitcoinaddress>@bitmessage.ch], .[firstname.lastname@example.org].master, .aleta, .crypton, .gryphon, .payday
Ransom note file names:
#_HOW_TO_FIX_!.hta, READ ME.txt, #_HOW_TO_FIX.inf, .!#_DECRYPT_#!.inf, !#_RESTORE_FILES_#!.INF, .HELP.txt, !! RETURN FILES !!.txt
Email addresses associated with BTCWare:
email@example.com, firstname.lastname@example.org, email@example.com, firstname.lastname@example.org, email@example.com, firstname.lastname@example.org, email@example.com
Telegram usernames associated with BTCWare:
Malware executables associated with BTCWare:
mfskskfkls.exe, <ransom>.exe, czsdxxs.exe
UPDATE 5/16/2017: BTCWare master key was released and the free decryption tool linked below has been updated to include most versions of this variant.
UPDATE 7/5/2017: The free decryption tool provided by Bleeping Computer has been updated to decrypt files from the most recent versions of BTCWare.
UPDATE 8/11/2017: A new version of BTCWare, dubbed Gryphon, was spotted in the wild. This version appends .crypton or .gryphon to the names of encrypted files and drops a ransom note named HELP.txt. There is no free decryption tool available for Gryphon at this time.
UPDATE 8/28/2017: A new version of BTCWare, dubbed Nuclear, was discovered appending .[email_address].nuclear to the names of encrypted files and dropping a ransom note named HELP.hta. Associated email addresses include firstname.lastname@example.org. There is no free decryption tool available for Nuclear at this time.
UPDATE 9/22/2017: A new version, dubbed Wyvern, was discovered appending .[email]-id-[id].wyvern to the names of encrypted files and dropping a ransom note named HELP.hta. Associated email addresses include email@example.com. There is no free decryption tool available for Wyvern at this time.
UPDATE 12/06/2017: A new version, dubbed Shadow, was discovered appending .[email]-id-id.shadow to the names of encrypted files. Associated email addresses include firstname.lastname@example.org. There is no free decryption tool available for Shadow at this time.
Image Source: PCrisk.com