A new exploit kit has arrived which is spreading different versions of Locky ransomware. We spotted two cases of this new threat, which is based on the earlier Sundown exploit kit. Sundown rose to prominence (together with Rig) after the then-dominant Neutrino exploit kit was neutralized.

Called Bizarro Sundown, the first version was spotted on October 5 with a second sighting two weeks later, on October 19. Users in Taiwan and Korea made up more than half of the victims of this threat. Bizarro Sundown shares some features with its Sundown predecessor but added anti-analysis features. The October 19 attack also changed its URL format to closely resemble legitimate web advertisements. Both versions were used exclusively by the ShadowGate/WordsJS campaign.