Kusto Query Language (KQL) For Threat Hunting

Head over to https://aka.ms/jakh to learn more.

You Should Know:

Kusto Query Language (KQL) is a powerful tool for cybersecurity professionals, especially in threat hunting and log analysis within Microsoft Sentinel and Azure Defender. Below are essential KQL commands, techniques, and best practices to enhance your threat-hunting skills.

Basic KQL Commands for Threat Hunting

// 1. Filtering Security Events 
SecurityEvent 
| where EventID == 4625 // Failed logins 
| where AccountType == "User" 
| project TimeGenerated, Computer, AccountName, IpAddress

// 2. Detecting Suspicious Process Execution 
DeviceProcessEvents 
| where FileName in~ ("powershell.exe", "cmd.exe") 
| where InitiatingProcessFileName != "explorer.exe" 
| project Timestamp, DeviceName, FileName, CommandLine

// 3. Hunting for Network Anomalies 
DeviceNetworkEvents 
| where RemoteIPType == "Public" 
| where ActionType == "ConnectionSuccess" 
| summarize ConnectionCount = count() by RemoteIP, DeviceName 
| where ConnectionCount > 100

Advanced KQL Techniques

// 4. Joining Tables for Deeper Analysis 
SecurityEvent 
| where EventID == 4688 // Process creation 
| join ( 
DeviceFileEvents 
| where FileName endswith ".exe" 
) on $left.ProcessId == $right.ProcessId

// 5. Time-Based Threat Hunting (Last 7 Days) 
let lookback = 7d; 
SecurityAlert 
| where TimeGenerated > ago(lookback) 
| where AlertSeverity == "High" 
| summarize Count = count() by AlertName

Automating Threat Detection with KQL

// 6. Scheduled Query for Persistent Threats 
let maliciousIPs = datatable(IP:string) [ "1.1.1.1", "2.2.2.2" ]; 
DeviceNetworkEvents 
| where RemoteIP in (maliciousIPs) 
| extend GeoIP = geo_info_from_ip_address(RemoteIP)

What Undercode Say

KQL is indispensable for modern cybersecurity operations, enabling real-time log analysis and threat detection. Mastering KQL allows security teams to:
– Detect anomalies in authentication logs (EventID 4625).
– Track suspicious processes (DeviceProcessEvents).
– Analyze network traffic (DeviceNetworkEvents).
– Automate threat hunting with scheduled queries.

For hands-on practice, deploy a Microsoft Sentinel lab and experiment with sample datasets.