A Zebrocy Go Downloader

[harlan4096]

Last year at SAS2018 in Cancun, Mexico, “Masha and these Bears” included discussion of a subset of Sofacy activity and malware that we call “Zebrocy”, and predictions for the decline of SPLM/XAgent Sofacy activity coinciding with the acceleration of Zebrocy activity and innovation. Zebrocy was initially introduced as a Sofacy backdoor package in 2015, but the Zebrocy cluster has carved a new approach to malware development and delivery to the world of Sofacy. In line with this approach, we will present more on this Zebrocy innovation and activity playing out at SAS 2019 in Singapore.

Our colleagues at Palo Alto recently posted an analysis of Zebrocy malware. The analysis is good and marked their first detection of a Zebrocy Go variant as October 11, 2018. Because there is much to this cluster, clarifying and adding to the discussion is always productive.

Our original “Zebrocy Innovates – Layered Spearphishing Attachments and Go Downloaders” June 2018 writeup documents the very same downloader, putting the initial deployment of Zebrocy Go downloader activity at May 10, 2018. And while the targeting in the May event was most likely different from the October event, we documented this same Go downloader and same C2 was used to target a Kyrgyzstan organization. Also interesting is that the exact same system was a previous Zebrocy target earlier in 2018. So, knowing that this same activity is being reported on as “new” six months later tells us a bit about the willingness of this group to re-use rare components and infrastructure across different targets.

Full reading: https://securelist.com/a-zebrocy-go-downloader/89419/