PowerShellEncodedCommandsExecuted.md

All Encoded Powershell Commands

Query Information

MITRE ATT&CK Technique(s)

Technique ID	Title	Link
T1027	Obfuscated Files or Information	https://attack.mitre.org/techniques/T1027/

Defender XDR

let EncodedList = dynamic(['-encodedcommand', '-enc']); 
// For more results use line below en filter one above. This will also return more FPs.
// let EncodedList = dynamic(['-encodedcommand', '-enc', '-e']);
let TimeFrame = 48h; //Customizable h = hours, d = days
DeviceProcessEvents
| where Timestamp > ago(TimeFrame)
| where ProcessCommandLine contains "powershell" or InitiatingProcessCommandLine contains "powershell"
| where ProcessCommandLine has_any (EncodedList) or InitiatingProcessCommandLine has_any (EncodedList)
| extend base64String = extract(@'\s+([A-Za-z0-9+/]{20}\S+$)', 1, ProcessCommandLine)
| extend DecodedCommandLine = base64_decode_tostring(base64String)
| extend DecodedCommandLineReplaceEmptyPlaces = replace_string(DecodedCommandLine, '\u0000', '')
| where isnotempty(base64String) and isnotempty(DecodedCommandLineReplaceEmptyPlaces)
| summarize UniqueExecutionsList = make_set(DecodedCommandLineReplaceEmptyPlaces) by DeviceName
| extend TotalUniqueEncodedCommandsExecuted = array_length(UniqueExecutionsList)
| project DeviceName, TotalUniqueEncodedCommandsExecuted, UniqueExecutionsList
| sort by TotalUniqueEncodedCommandsExecuted

Sentinel

let EncodedList = dynamic(['-encodedcommand', '-enc']); 
// For more results use line below en filter one above. This will also return more FPs.
// let EncodedList = dynamic(['-encodedcommand', '-enc', '-e']);
let TimeFrame = 48h; //Customizable h = hours, d = days
DeviceProcessEvents
| where Timestamp > ago(TimeFrame)
| where ProcessCommandLine contains "powershell" or InitiatingProcessCommandLine contains "powershell"
| where ProcessCommandLine has_any (EncodedList) or InitiatingProcessCommandLine has_any (EncodedList)
| extend base64String = extract(@'\s+([A-Za-z0-9+/]{20}\S+$)', 1, ProcessCommandLine)
| extend DecodedCommandLine = base64_decode_tostring(base64String)
| extend DecodedCommandLineReplaceEmptyPlaces = replace_string(DecodedCommandLine, '\u0000', '')
| where isnotempty(base64String) and isnotempty(DecodedCommandLineReplaceEmptyPlaces)
| summarize UniqueExecutionsList = make_set(DecodedCommandLineReplaceEmptyPlaces) by DeviceName
| extend TotalUniqueEncodedCommandsExecuted = array_length(UniqueExecutionsList)
| project DeviceName, TotalUniqueEncodedCommandsExecuted, UniqueExecutionsList
| sort by TotalUniqueEncodedCommandsExecuted