Query: write Sigma for 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 execution of "tar.exe" in order to create a compressed file. Adversaries may abuse various utilities to compress. Logsource: windows / process_creation. Rule: title: Compressed File Creation Via Tar.EXE id: 418a3163-3247-4b7b-9933-dcfcb7c52ea9 status: test description: 'Detects execution of "tar.exe" in order to create a compressed file. Adversaries may abuse various utilities to compress or encrypt data before exfiltration. ' references: - https://unit42.paloaltonetworks.com/chromeloader-malware/ - https://lolbas-project.github.io/lolbas/Binaries/Tar/ - https://symantec-enterprise-blogs.security.com/blogs/threat-intelligence/cicada-apt10-japan-espionage author: Nasreddine Bencherchali (Nextron Systems), AdmU3 date: 2023-12-19 tags: - attack.collection - attack.exfiltration - attack.t1560 - attack.t1560.001 logsource: product: windows category: process_creation detection: selection_img: - Image|endswith: \tar.exe - OriginalFileName: bsdtar selection_create: CommandLine|contains: - -c - -r - -u condition: all of selection_* falsepositives: - Likely level: low