Cloud Threats Memo: LinkedIn Spearphishing and Malware-as-a-Service

‘More_eggs’ is a backdoor sold as a “malware-as-a-service” (MaaS) by a threat group known as “Golden Chickens” and predominantly used by three criminal groups: FIN6, Cobalt Group, and Evilnum.

In the latest campaign, unearthed by researchers from eSentire and targeting a professional working in the healthcare technology industry, a threat actor is exploiting fake job offers on LinkedIn to deploy the ‘More_eggs’ backdoor on the victim’s machine.

This is yet another interesting example of a campaign exploiting multiple cloud services to evade detection, and preying on COVID-19 uncertainty, given the high number of job redundancies deriving from the pandemic. Not only is LinkedIn used to spearphish the victim via a malicious zip file with a fake job offer using the position listed on the target’s public profile, but also AWS contributes to the attack chain, being exploited to deliver the TerraPreter payload, an ActiveX control used to beacon to the Command & Control server (C2).

How Netskope mitigates this threat

Linkedin and AWS are among the thousands of applications for which the Netskope Next Gen SWG provides granular adaptive access control and threat protection. To prevent similar attacks exploiting LinkedIn (and in general any personal or professional social network) it is possible to apply a block, or warn the user when a download activity is performed, allowing only those activities considered harmless, or even to enforce the multi-stage Netskope threat protection engine to scan any downloaded content.

An even more granular policy is possible for AWS where an organization can define its own AWS instances and which S3 buckets belong to those so that more restrictive blocks can be applied for activities performed on non-corporate resources. Of course, it is also always possible to scan the downloads to detect any malicious content retrieved from AWS and hence interrupt the kill chain. 

Stay safe!