First discovered in early 2014, CryptoWall is a ransomware from the same group that made CryptoDefense.
CryptoWall improved on some features of CryptoDefense, including using java vulnerabilities through malvertisements on popular websites, and not storing the encryption key to prevent decryption.
CryptoWall is delivered through malicious emails with zipped executables posing as PDF files as well as using the Nuclear Exploit Kit.
CryptoWall can run on 32-bit and 64-bit operating systems allowing compatibility with more operating systems.
Ransoms are reported to be between $200 and $10,000 in BitCoin.
If you are interested in learning about other Ransomware families that we have published research reports on you can read more here