{"id":"e6c54d94-498c-4562-a37c-b469d8e9a275","title":"Suspicious PowerShell Download and Execute Pattern","description":"Detects suspicious PowerShell download patterns that are often used in malicious scripts, stagers or downloaders (make sure that your backend applies the strings case-insensitive)","author":"Florian Roth (Nextron Systems)","status":"test","level":"high","date":"2022-02-28","modified":"2022-03-01","tags":["attack.execution","attack.t1059.001"],"technique_ids":["T1059.001"],"logsource":{"category":"process_creation","product":"windows"},"falsepositives":["Software installers that pull packages from remote systems and execute them"],"references":["https://gist.github.com/jivoi/c354eaaf3019352ce32522f916c03d70","https://www.trendmicro.com/en_us/research/22/j/lv-ransomware-exploits-proxyshell-in-attack.html"],"source_path":"rules/windows/process_creation/proc_creation_win_powershell_susp_download_patterns.yml","source_sha256":"4b8a1d1c7bca807dea94df192f709138b17ca4e8d8b0c02eb2c0eafa9da3b446","source_url":"https://github.com/anpa1200/sigma/blob/b249e9683190cffdcaf188ccbfb90bf4759844e1/rules/windows/process_creation/proc_creation_win_powershell_susp_download_patterns.yml","license":"Detection Rule License 1.1","license_url":"https://github.com/SigmaHQ/Detection-Rule-License/blob/main/LICENSE.Detection.Rules.md","yaml":"title: Suspicious PowerShell Download and Execute Pattern\nid: e6c54d94-498c-4562-a37c-b469d8e9a275\nrelated:\n    - id: 3b6ab547-8ec2-4991-b9d2-2b06702a48d7\n      type: derived\nstatus: test\ndescription: Detects suspicious PowerShell download patterns that are often used in malicious scripts, stagers or downloaders (make sure that your backend applies the strings case-insensitive)\nreferences:\n    - https://gist.github.com/jivoi/c354eaaf3019352ce32522f916c03d70\n    - https://www.trendmicro.com/en_us/research/22/j/lv-ransomware-exploits-proxyshell-in-attack.html\nauthor: Florian Roth (Nextron Systems)\ndate: 2022-02-28\nmodified: 2022-03-01\ntags:\n    - attack.execution\n    - attack.t1059.001\nlogsource:\n    category: process_creation\n    product: windows\ndetection:\n    selection:\n        CommandLine|contains: # make sure that your backend applies the strings case-insensitive\n            - 'IEX ((New-Object Net.WebClient).DownloadString'\n            - 'IEX (New-Object Net.WebClient).DownloadString'\n            - 'IEX((New-Object Net.WebClient).DownloadString'\n            - 'IEX(New-Object Net.WebClient).DownloadString'\n            - ' -command (New-Object System.Net.WebClient).DownloadFile('\n            - ' -c (New-Object System.Net.WebClient).DownloadFile('\n    condition: selection\nfalsepositives:\n    - Software installers that pull packages from remote systems and execute them\nlevel: high\n","validation":"yaml_parsed_not_backend_compiled_or_live_validated","techniques":[{"key":"enterprise/T1059.001","id":"T1059.001","name":"PowerShell","page":"techniques/enterprise/T1059.001/"}],"data_path":"data/detection-rules/e6c54d94-498c-4562-a37c-b469d8e9a275.json","kind":"sigma"}