{"id":"cdc8da7d-c303-42f8-b08c-b4ab47230263","title":"Rundll32 Internet Connection","description":"Detects a rundll32 that communicates with public IP addresses","author":"Florian Roth (Nextron Systems)","status":"test","level":"medium","date":"2017-11-04","modified":"2024-03-13","tags":["attack.stealth","attack.t1218.011","attack.execution"],"technique_ids":["T1218.011"],"logsource":{"category":"network_connection","product":"windows"},"falsepositives":["Communication to other corporate systems that use IP addresses from public address spaces"],"references":["https://www.hybrid-analysis.com/sample/759fb4c0091a78c5ee035715afe3084686a8493f39014aea72dae36869de9ff6?environmentId=100"],"source_path":"rules/windows/network_connection/net_connection_win_rundll32_net_connections.yml","source_sha256":"eb22c396d43e207c3bcd5e97425d30ba4b31111127bce2e85863a1fb53c3d2d2","source_url":"https://github.com/anpa1200/sigma/blob/b249e9683190cffdcaf188ccbfb90bf4759844e1/rules/windows/network_connection/net_connection_win_rundll32_net_connections.yml","license":"Detection Rule License 1.1","license_url":"https://github.com/SigmaHQ/Detection-Rule-License/blob/main/LICENSE.Detection.Rules.md","yaml":"title: Rundll32 Internet Connection\nid: cdc8da7d-c303-42f8-b08c-b4ab47230263\nstatus: test\ndescription: Detects a rundll32 that communicates with public IP addresses\nreferences:\n    - https://www.hybrid-analysis.com/sample/759fb4c0091a78c5ee035715afe3084686a8493f39014aea72dae36869de9ff6?environmentId=100\nauthor: Florian Roth (Nextron Systems)\ndate: 2017-11-04\nmodified: 2024-03-13\ntags:\n    - attack.stealth\n    - attack.t1218.011\n    - attack.execution\nlogsource:\n    category: network_connection\n    product: windows\ndetection:\n    selection:\n        Image|endswith: '\\rundll32.exe'\n        Initiated: 'true'\n    filter_main_local_ranges:\n        DestinationIp|cidr:\n            - '127.0.0.0/8'\n            - '10.0.0.0/8'\n            - '172.16.0.0/12'\n            - '192.168.0.0/16'\n            - '169.254.0.0/16'\n            - '::1/128'  # IPv6 loopback\n            - 'fe80::/10'  # IPv6 link-local addresses\n            - 'fc00::/7'  # IPv6 private addresses\n    filter_main_ms_ranges:\n        DestinationIp|cidr:\n            - '20.0.0.0/8' # Microsoft range, caused some FPs\n            - '51.103.0.0/16' # Microsoft AS8075 range, caused some FPs\n            - '51.104.0.0/16' # Microsoft AS8075 range, caused some FPs\n            - '51.105.0.0/16' # Microsoft AS8075 range, caused some FPs\n    filter_main_app_sdb:\n        CommandLine|endswith: '\\system32\\PcaSvc.dll,PcaPatchSdbTask'\n    filter_main_azure_managed:\n        SourceHostname|endswith: '.internal.cloudapp.net'\n    filter_main_svchost_update_processes:\n        # Note: This require \"ParentImage\" data enrichment.\n        ParentImage: 'C:\\Windows\\System32\\svchost.exe'\n        DestinationPort: 443\n    condition: selection and not 1 of filter_main_*\nfalsepositives:\n    - Communication to other corporate systems that use IP addresses from public address spaces\nlevel: medium\n","validation":"yaml_parsed_not_backend_compiled_or_live_validated","techniques":[{"key":"enterprise/T1218.011","id":"T1218.011","name":"Rundll32","page":"techniques/enterprise/T1218.011/"}],"data_path":"data/detection-rules/cdc8da7d-c303-42f8-b08c-b4ab47230263.json","kind":"sigma"}