Query: rule covering Detects PowerShell download activity, via the .DownloadFile() or .DownloadString() methods of the Net.WebClient class. T
Matching passage: Sigma rule: Detects PowerShell download activity, via the .DownloadFile() or .DownloadString() methods of the Net.WebClient class. T. Logsource: windows / ps_classic_start. Rule: title: PowerShell Download Via Net.WebClient - PowerShell Classic id: 3236fcd0-b7e3-4433-b4f8-86ad61a9af2d related: - id: 65531a81-a694-4e31-ae04-f8ba5bc33759 type: derived status: test description: 'Detects PowerShell download activity, via the .DownloadFile() or .DownloadString() methods of the Net.WebClient class. This technique is often abused by attackers to download additional payloads. ' references: - https://www.trendmicro.com/en_us/research/22/j/lv-ransomware-exploits-proxyshell-in-attack.html author: Florian Roth (Nextron Systems) date: 2017-03-05 modified: 2026-04-28 tags: - attack.execution - attack.command-and-control - attack.t1059.001 - attack.t1105 logsource: product: windows category: ps_classic_start detection: selection_webclient: Data|contains: Net.WebClient selection_download: Data|contains: - .DownloadFile( - .DownloadString( condition: all of selection_* falsepositives: - This activity may be used by legitimate software, such as patch management tools or software updaters. Investigate any such activity and apply the necessary filter. level: low
Near-miss passage: Sigma rule: Detects scheduled task creation using "schtasks" that contain potentially suspicious or uncommon commands. Logsource: windows / process_creation. Rule: title: Suspicious Command Patterns In Scheduled Task Creation id: f2c64357-b1d2-41b7-849f-34d2682c0fad status: test description: Detects scheduled task creation using "schtasks" that contain potentially suspicious or uncommon commands references: - https://app.any.run/tasks/512c1352-6380-4436-b27d-bb62f0c020d6/ - https://twitter.com/RedDrip7/status/1506480588827467785 - https://www.ncsc.gov.uk/static-assets/documents/malware-analysis-reports/devil-bait/NCSC-MAR-Devil-Bait.pdf author: Florian Roth (Nextron Systems) date: 2022-02-23 modified: 2024-03-19 tags: - attack.privilege-escalation - attack.persistence - attack.execution - attack.t1053.005 logsource: product: windows category: process_creation detection: selection_schtasks: Image|endswith: \schtasks.exe CommandLine|contains: '/Create ' selection_pattern_1: CommandLine|contains: - '/sc minute ' - '/ru system ' selection_pattern_2: CommandLine|contains: - cmd /c - cmd /k - cmd /r - 'cmd.exe /c ' - 'cmd.exe /k ' - 'cmd.exe /r ' selection_uncommon: CommandLine|contains: - ' -decode ' - ' -enc ' - ' -w hidden ' - ' bypass ' - ' IEX' - .DownloadData - .DownloadFile - .DownloadString - '/c start /min ' - FromBase64String - mshta http - mshta.exe http selection_anomaly_1: CommandLine|contains: - :\ProgramData\ - :\Temp\ - :\Tmp\ - :\Users\Public\ - :\Windows\Temp\ - \AppData\ - '%AppData%' - '%Temp%' - '%tmp%' selection_anomaly_2: CommandLine|contains: - cscript - curl - wscript condition: selection_schtasks and ( all of selection_pattern_* or selection_uncommon or all of selection_anomaly_* ) falsepositives: - Software installers that run from temporary folders and also install scheduled tasks are expected to generate some false positives level: high