[CB16] PowerShell obfuskation Techniques & How To Detect Them​ by Daniel Bohannon

[CB16] Invoke-Obfuscation: PowerShell obFUsk8tion Techniques & How To (Try To) D""e`Tec`T 'Th'+'em'​ by Daniel Bohannon

We need new avenues to remain stealthy in a target environment. So, this talk will highlight a dozen never-before-seen techniques for obfuscating PowerShell command line arguments. As an incident responder at Mandiant, I have seen attackers use a handful of these methods to evade basic command line detection mechanisms. I will share these techniques already being used in the wild so you can understand the value each technique provides the attacker.
Updated PowerShell event logging mitigates many of the detection challenges that obfuscation introduces. However, many organizations do not enable this PowerShell logging. Therefore, I will provide techniques that the Blue Team can use to detect the presence of these obfuscation methods in command line arguments. I will conclude this talk by highlighting the public release of Invoke-Obfuscation. This tool applies the aforementioned obfuscation techniques to user-provided commands and scripts to evade command line argument detection mechanisms.

-- Daniel Bohannon
Daniel Bohannon is an Incident Response Consultant at MANDIANT with over six years of operations and information security experience. His particular areas of expertise include enterprise-wide incident response investigations, host-based security monitoring, data aggregation and anomaly detection, and PowerShell-based attack research and detection techniques. As an incident response consultant, Mr. Bohannon provides emergency services to clients when security breach occur. He also develops new methods for detecting malicious PowerShell usage at both the host- and network-level while researching obfuscation techniques for PowerShell- based attacks that are being used by numerous threat groups. Prior to joining MANDIANT, Mr. Bohannon spent five years working in both IT operations and information security roles in the private retail industry. There he developed operational processes for the automated aggregation and detection of host- and network-based anomalies in a large PCI environment. Mr. Bohannon also programmed numerous tools for host-based hunting while leading the organization’s incident response team. Mr. Bohannon received a Master of Science in Information Security from the Georgia Institute of Technology and a Bachelor of Science in Computer Science from The University of Georgia.