Monitoring with PowerShell: Alerting on Shodan results

This is a bit of a short script again – but that’s just because sometimes life can made be real simple. Shodan is a tool that scans the entire internet and documents which open ports are available, if it is vulnerable for specific CVE’s, and lots of cool other stuff explained here.

We’ve seen some MSP’s offer a simple Shodan query and selling it as a “Dark Web Scan” – Please note that this is absolutely not a comprehensive scan and finding online exposed services is not always such a big deal, for example in controlled environments.

The script I’ve made is one we run at our clients on IP addresses where we know nothing should be listed in Shodan, networks that should not have exposed services, or just IP addresses where we want to alert on changes. Simply change the list of IPs to the list you would like to monitor.

$APIKEY = "YourShodanAPIKey"
$CurrentIP = (Invoke-WebRequest -uri "http://ifconfig.me/ip" -UseBasicParsing ).Content
$ListIPs = @("1.1.1.1","2.2.2.2",$CurrentIP)
foreach($ip in $ListIPs){
   $Shodan = Invoke-RestMethod -uri "https://api.shodan.io/shodan/host/$($ip)?key=$APIKEY"
}
if(!$Shodan) { $HealthState = "Healthy"} else { $HealthState = "Alert - $($Shodan.ip_str) is found in Shodan."} 

We also like running these scripts at our prospects as a part of a security survey, because if Shodan has found external services such as RDP on a different port it often shows bad security practices as a whole.

Getting a Shodan subscription is absolutely worth it because it gives you that little bit more of visibility on how exposed you actually. Anyway, as always happy PowerShelling!

Kelvin Tegelaar
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