Query: rule covering Detects Base64 encoded Shellcode
Matching passage: Sigma rule: Detects Base64 encoded Shellcode. Logsource: windows / ps_script. Rule: title: PowerShell ShellCode id: 16b37b70-6fcf-4814-a092-c36bd3aafcbd status: test description: Detects Base64 encoded Shellcode references: - https://twitter.com/cyb3rops/status/1063072865992523776 author: David Ledbetter (shellcode), Florian Roth (Nextron Systems) date: 2018-11-17 modified: 2024-01-25 tags: - attack.privilege-escalation - attack.stealth - attack.t1055 - attack.execution - attack.t1059.001 logsource: product: windows category: ps_script definition: 'Requirements: Script Block Logging must be enabled' detection: selection: ScriptBlockText|contains: - OiCAAAAYInlM - OiJAAAAYInlM condition: selection falsepositives: - Unknown level: high
Near-miss passage: Sigma rule: Detects registry value settings that would replace the user's desktop background. This is a common technique used by mal. Logsource: windows / registry_set. Rule: title: Potentially Suspicious Desktop Background Change Via Registry id: 85b88e05-dadc-430b-8a9e-53ff1cd30aae related: - id: 8cbc9475-8d05-4e27-9c32-df960716c701 type: similar status: test description: 'Detects registry value settings that would replace the user''s desktop background. This is a common technique used by malware to change the desktop background to a ransom note or other image. ' references: - https://www.attackiq.com/2023/09/20/emulating-rhysida/ - https://research.checkpoint.com/2023/the-rhysida-ransomware-activity-analysis-and-ties-to-vice-society/ - https://www.trendmicro.com/en_us/research/23/h/an-overview-of-the-new-rhysida-ransomware.html - https://www.virustotal.com/gui/file/a864282fea5a536510ae86c77ce46f7827687783628e4f2ceb5bf2c41b8cd3c6/behavior - https://admx.help/?Category=Windows_10_2016&Policy=Microsoft.Policies.WindowsDesktop::Wallpaper - https://admx.help/?Category=Windows_10_2016&Policy=Microsoft.Policies.ControlPanelDisplay::CPL_Personalization_NoDesktopBackgroundUI author: Nasreddine Bencherchali (Nextron Systems), Stephen Lincoln @slincoln-aiq (AttackIQ) date: 2023-12-21 modified: 2025-10-17 tags: - attack.persistence - attack.impact - attack.defense-impairment - attack.t1112 - attack.t1491.001 logsource: product: windows category: registry_set detection: selection_keys: TargetObject|contains: - Control Panel\Desktop - CurrentVersion\Policies\ActiveDesktop - CurrentVersion\Policies\System selection_values_1: TargetObject|endswith: NoChangingWallpaper Details: DWORD (0x00000001) selection_values_2: TargetObject|endswith: \Wallpaper selection_values_3: TargetObject|endswith: \WallpaperStyle Details: '2' filter_main_svchost: Image|endswith: \svchost.exe filter_main_empty: TargetObject|endswith: \Control Panel\Desktop\Wallpaper Details: (Empty) filter_main_explorer: Image|endswith: C:\Windows\Explorer.EXE filter_optional_ec2launch: Image: - C:\Program Files\Amazon\EC2Launch\EC2Launch.exe - C:\Program Files (x86)\Amazon\EC2Launch\EC2Launch.exe TargetObject|endswith: \Control Panel\Desktop\Wallpaper condition: selection_keys and 1 of selection_values_* and not 1 of filter_main_* and not 1 of filter_optional_* falsepositives: - Administrative scripts that change the desktop background to a company logo or other image. level: medium