From the beginning of this year, we are observing rapid development of DMA Locker. First, the threat was too primitive to even treat it seriously. Then it evolved to more complex but still decryptable ransomware.
The 3.0 edition was very similar to the previous one that we described, so we skipped posting about its details (the only change was to fix the bug making it decryptable). Now we are facing an outbreak of version 4.0, coming with various changes.
In the past, DMA Locker was known from being installed on hacked Remote Desktops. New release has been found distributed via exploit kit (Neutrino). This change is another step towards maturity of the malware, showing that now this threat will be spreading on a bigger scale.
See DMA Locker development timeline:https://blog.malwarebytes.org/threat-analysis/2016/05/dma-locker-4-0-known-ransomware-preparing-for-a-massive-distribution/