LausivLoader analysis, or how to pass data between malware stages, (Thu, Sep 17th)
SANS dissects a LausivLoader JavaScript malspam sample that passes staged payload file paths to PowerShell via process environment variables.
SANS analyzed a LausivLoader JavaScript sample caught in a customer's mail gateway from an August malspam campaign impersonating a fiber-optic procurement inquiry. The roughly 613 KB attachment (28/55 VirusTotal detections) hides code among 450 junk comment lines, drops two files into a randomized %TEMP% directory, and passes their paths to a PowerShell payload via process environment variables Kv7408 and Kv562. The final command launches PowerShell through conhost.exe with a Base64-encoded command; the script also copies itself and attempts to register a scheduled task.
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