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Cyber Risks · Unit 42 Palo Alto Networks

Practical Behavioral Profiling of Power Shell Scripts through Static Analysis (Part 2)

Summary: Unit 42's three-part blog series describes a platform-independent Python script for static analysis of PowerShell scripts, and Part 2 covers the design phase: stripping NULL bytes so ASCII matching works, then repeatedly normalizing and de-obfuscating content until the script's state stops changing. The script targets eight obfuscation techniques, including backticks, carets, escaped and empty quotes, spaces, string concatenation, Format String Operator Replacement (which the post says rose sharply after Daniel Bohannon released Invoke-Obfuscation), and PowerShell's built-in string replacement, then scores behaviors across malicious, neutral, and benign categories with a target verdict range of 6 or higher.

Bottom line: The post states the script's REGEX patterns only capture the variants found in its sample set, so coverage depends on analysts adding new families such as Magic Unicorn, SET, and Veil as they appear in the wild.

Read the original at Unit 42 Palo Alto Networks ↗

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Malware
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