Use of Open Source Tools In an attempt to avoid detection and as an anti-analysis tactic, the OilRig group abused an open source tool called Invoke-Obfuscation to obfuscate the code used for QUADAGENT. Invoke-Obfuscation is freely available via a Github repository and allows a user to change the visual representation of a PowerShell script simply by selecting the desired obfuscation techniques. Invoke-Obfuscation offers a variety of obfuscation techniques, and by analyzing the script we were able to ascertain the specific options in this attack. After identifying the specific options used to obfuscate QUADAGENT, we were able to deobfuscate the PowerShell script and perform additional analysis. We found two obfuscation techniques applied to the script: the first one changing the representation of variables; the second one changing the representation of strings in the script. Invoke-Obfuscation calls the string obfuscation used by the actors to further obfuscate this script Reorder, which uses the string formatting functionality within PowerShell to reconstruct strings from out of order substrings (ex. 1}{0}" -f 'bar','foo'). During our analysis, we installed Invoke-Obfuscation and used it to obfuscate a previously collected QUADAGENT sample to confirm our analysis