Query: detection rule: Detects Windows executables that write files with suspicious extensions
Matching passage: Sigma rule: Detects Windows executables that write files with suspicious extensions. Logsource: windows / file_event. Rule: title: Windows Binaries Write Suspicious Extensions id: b8fd0e93-ff58-4cbd-8f48-1c114e342e62 related: - id: 1277f594-a7d1-4f28-a2d3-73af5cbeab43 type: derived status: test description: Detects Windows executables that write files with suspicious extensions references: - Internal Research author: Nasreddine Bencherchali (Nextron Systems) date: 2022-08-12 modified: 2025-10-07 tags: - attack.stealth - attack.t1036 logsource: category: file_event product: windows detection: selection_generic: Image|endswith: - \csrss.exe - \lsass.exe - \RuntimeBroker.exe - \sihost.exe - \smss.exe - \wininit.exe - \winlogon.exe TargetFilename|endswith: - .bat - .dll - .exe - .hta - .iso - .ps1 - .txt - .vbe - .vbs selection_special: Image|endswith: - \dllhost.exe - \rundll32.exe - \svchost.exe TargetFilename|endswith: - .bat - .hta - .iso - .ps1 - .vbe - .vbs filter_main_AppLockerPolicyTest: Image: C:\Windows\System32\dllhost.exe TargetFilename|contains|all: - :\Users\ - \AppData\Local\Temp\__PSScriptPolicyTest_ TargetFilename|endswith: .ps1 filter_main_script_gpo_machine: Image: C:\Windows\system32\svchost.exe TargetFilename|contains|all: - C:\Windows\System32\GroupPolicy\DataStore\ - \sysvol\ - \Policies\ - \Machine\Scripts\Startup\ TargetFilename|endswith: - .ps1 - .bat filter_main_clipchamp: Image: C:\Windows\system32\svchost.exe TargetFilename|contains|all: - C:\Program Files\WindowsApps\Clipchamp - .ps1 filter_main_powershell_preview: Image: - C:\Windows\system32\svchost.exe - C:\Windows\SysWOW64\svchost.exe TargetFilename|startswith: - C:\Program Files\WindowsApps\Microsoft.PowerShellPreview - C:\Program Files (x86)\WindowsApps\Microsoft.PowerShellPreview TargetFilename|endswith: .ps1 condition: 1 of selection_* and not 1 of filter_main_* falsepositives: - Unknown level: high
Near-miss passage: Sigma rule: Detects execution of a browser process with a URL argument pointing to a file with a potentially interesting extension.. Logsource: windows / process_creation. Rule: title: File Download From Browser Process Via Inline URL id: 94771a71-ba41-4b6e-a757-b531372eaab6 status: test description: Detects execution of a browser process with a URL argument pointing to a file with a potentially interesting extension. This can be abused to download arbitrary files or to hide from the user for example by launching the browser in a minimized state. references: - https://twitter.com/mrd0x/status/1478116126005641220 - https://lolbas-project.github.io/lolbas/Binaries/Msedge/ author: Florian Roth (Nextron Systems), Nasreddine Bencherchali (Nextron Systems) date: 2022-01-11 modified: 2025-10-27 tags: - attack.command-and-control - attack.t1105 logsource: category: process_creation product: windows detection: selection_img: Image|endswith: - \brave.exe - \chrome.exe - \msedge.exe - \opera.exe - \vivaldi.exe selection_http: CommandLine|contains: http selection_extensions: - CommandLine|endswith: - .7z - .dat - .dll - .exe - .hta - .ps1 - .psm1 - .txt - .vbe - .vbs - .zip - CommandLine|contains: - .7z" - .dat" - .dll" - .hta" - .ps1" - .psm1" - .txt" - .vbe" - .vbs" - .zip" condition: all of selection_* falsepositives: - Unknown level: medium regression_tests_path: regression_data/rules/windows/process_creation/proc_creation_win_browsers_inline_file_download/info.yml