KQL Search

//Use logon and network telemetry to find machines exposed to the internet, then count the critical and high severity vulnerabilities on those devices
//This query only works in Advanced Hunting as the DeviceTvm* tables aren't sent to Sentinel yet

//Data connector required for this query - Advanced Hunting license

//Look for logon events coming from a public IP - query adapted from https://github.com/alexverboon/MDATP/blob/master/AdvancedHunting/Failed%20Logon%20-%20Public%20IP.md
let publicips = 
    DeviceLogonEvents
    | where Timestamp > ago(30d)
    | where ActionType in ("LogonFailed", "LogonSuccess")
    | where RemoteIPType == "Public"
    | distinct RemoteIP;
//Use that same list of IP addresses to search for network traffic coming from those IP's, suggesting the device is available on the internet
let publicdevices=
    DeviceNetworkEvents
    | where Timestamp > ago (30d)
    | where RemoteIPType == "Public"
    | where RemoteIP in (publicips)
    | distinct DeviceName;
//Find the high and critical vulnerability count for those devices
DeviceTvmSoftwareVulnerabilities
| where DeviceName in (publicdevices)
| summarize ['Vulnerability Count']=dcountif(CveId, VulnerabilitySeverityLevel in ("Critical", "High")) by DeviceName
| sort by ['Vulnerability Count'] desc