Query: rule covering Detects the execution of "reg.exe" to alter registry keys that would replace the user's desktop background. This is a co
Matching passage: Sigma rule: Detects the execution of "reg.exe" to alter registry keys that would replace the user's desktop background. This is a co. Logsource: windows / process_creation. Rule: title: Potentially Suspicious Desktop Background Change Using Reg.EXE id: 8cbc9475-8d05-4e27-9c32-df960716c701 related: - id: 85b88e05-dadc-430b-8a9e-53ff1cd30aae type: similar status: test description: 'Detects the execution of "reg.exe" to alter registry keys 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: Stephen Lincoln @slincoln-aiq (AttackIQ) date: 2023-12-21 tags: - attack.persistence - attack.impact - attack.defense-impairment - attack.t1112 - attack.t1491.001 logsource: product: windows category: process_creation detection: selection_reg_img: - Image|endswith: \reg.exe - OriginalFileName: reg.exe selection_reg_flag: CommandLine|contains: add selection_keys: CommandLine|contains: - Control Panel\Desktop - CurrentVersion\Policies\ActiveDesktop - CurrentVersion\Policies\System selection_cli_reg_1: CommandLine|contains|all: - /v NoChangingWallpaper - /d 1 selection_cli_reg_2: CommandLine|contains|all: - /v Wallpaper - /t REG_SZ selection_cli_reg_3: CommandLine|contains|all: - /v WallpaperStyle - /d 2 condition: all of selection_reg_* and selection_keys and 1 of selection_cli_reg_* falsepositives: - Administrative scripts that change the desktop background to a company logo or other image. level: medium
Near-miss passage: Sigma rule: Detects when a browser process or browser tab is launched from an application that handles document files such as Adobe,. Logsource: windows / process_creation. Rule: title: Potential Suspicious Browser Launch From Document Reader Process id: 1193d960-2369-499f-a158-7b50a31df682 status: test description: 'Detects when a browser process or browser tab is launched from an application that handles document files such as Adobe, Microsoft Office, etc. And connects to a web application over http(s), this could indicate a possible phishing attempt. ' references: - https://app.any.run/tasks/69c5abaa-92ad-45ba-8c53-c11e23e05d04/ - https://app.any.run/tasks/64043a79-165f-4052-bcba-e6e49f847ec1/ author: Joseph Kamau date: 2024-05-27 modified: 2025-10-07 tags: - attack.execution - attack.t1204.002 logsource: product: windows category: process_creation detection: selection: ParentImage|contains: - Acrobat Reader - Microsoft Office - PDF Reader Image|endswith: - \brave.exe - \chrome.exe - \firefox.exe - \msedge.exe - \opera.exe - \maxthon.exe - \seamonkey.exe - \vivaldi.exe CommandLine|contains: http filter_main_microsoft_help: CommandLine|contains: https://go.microsoft.com/fwlink/ filter_optional_foxit: CommandLine|contains: - http://ad.foxitsoftware.com/adlog.php? - https://globe-map.foxitservice.com/go.php?do=redirect condition: selection and not 1 of filter_main_* and not 1 of filter_optional_* falsepositives: - Unlikely in most cases, further investigation should be done in the commandline of the browser process to determine the context of the URL accessed. level: medium