rundll32_internet_connection

rule rundll32_internet_connection {
 meta:
    author = "Florian Roth"
    description = "Detects a rundll32 that communicates with public IP addresses  License: https://github.com/Neo23x0/sigma/blob/master/LICENSE.Detection.Rules.md."
    reference = "https://tdm.socprime.com/tdm/info/0Zg55ZhTC6ZE"
    version = "0.01"
    created = "2017/11/04"
    product = "windows"
    service = "sysmon"
    mitre = "t1085, defense_evasion, execution"

  events:
(($selection.metadata.product_event_type = "3" and re.regex($selection.target.process.file.full_path, `.*\\rundll32\.exe`)) and not ((re.regex($selection.target.ip, `10\..*`) or re.regex($selection.target.ip, `192\.168\..*`) or re.regex($selection.target.ip, `172\..*`))))

  condition:
    $selection
}