We’ve dubbed this activity cluster “Silver Sparrow.” The novelty of this downloader arises primarily from the way it uses JavaScript for execution-something we hadn’t previously encountered in other macOS malware-and the emergence of a related binary compiled for Apple’s new M1 ARM64 architecture. However, our investigation almost immediately revealed that this malware, whatever it was, did not exhibit the behaviors that we’ve come to expect from the usual adware that so often targets macOS systems. Other teams may cluster this activity differently based on their assessments.Įarlier this month, Red Canary detection engineers Wes Hurd and Jason Killam came across a strain of macOS malware using a LaunchAgent to establish persistence. A subset of those 29,139 machines were infected by one of the two malicious packages described in this blog, while the majority contained the `._insu` file check and were therefore affected by the overall Silver Sparrow activity cluster as we define it. One file we chose to include in the cluster is the `._insu` file that seems to instruct the malware to remove itself from an endpoint. This distinction may seem small, but it’s important because the Silver Sparrow activity cluster comprises multiple artifacts, including clearly malicious files and unusual or suspicious ones too. UPDATE on : A previous version of this blog stated that, “…Silver Sparrow had infected 29,139 macOS endpoints….” We have updated it to state that the Silver Sparrow activity cluster affected 29,139 macOS endpoints.

Silver sparrow malware how to detect