Query: alert when Detects registry value settings that would replace the user's desktop background. This is a common technique used by mal
Matching 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
Near-miss passage: Sigma rule: Detects successful deletion or disabling of an AWS GuardDuty detector, possibly by an attacker trying to avoid detection. Logsource: aws / cloudtrail. Rule: title: AWS GuardDuty Detector Deleted Or Updated id: d2656e78-c069-4571-8220-9e0ab5913f19 status: experimental description: 'Detects successful deletion or disabling of an AWS GuardDuty detector, possibly by an attacker trying to avoid detection of its malicious activities. Upon deletion, GuardDuty stops monitoring the environment and all existing findings are lost. Verify with the user identity that this activity is legitimate. ' references: - https://docs.aws.amazon.com/guardduty/latest/APIReference/API_DeleteDetector.html - https://docs.aws.amazon.com/guardduty/latest/APIReference/API_UpdateDetector.html - https://docs.aws.amazon.com/guardduty/latest/ug/guardduty_suspend-disable.html - https://docs.datadoghq.com/security/default_rules/719-39f-9cd/ - https://docs.prismacloud.io/en/enterprise-edition/policy-reference/aws-policies/aws-general-policies/ensure-aws-guardduty-detector-is-enabled - https://docs.stellarcyber.ai/5.2.x/Using/ML/Alert-Rule-Based-Potentially_Malicious_AWS_Activity.html - https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Amazon%20Web%20Services/Analytic%20Rules/AWS_GuardDutyDisabled.yaml - https://github.com/elastic/detection-rules/blob/main/rules/integrations/aws/defense_evasion_guardduty_detector_deletion.toml - https://help.fortinet.com/fsiem/Public_Resource_Access/7_4_0/rules/PH_RULE_AWS_GuardDuty_Detector_Deletion.htm - https://research.splunk.com/sources/5d8bd475-c8bc-4447-b27f-efa508728b90/ - https://suktech24.com/2025/07/17/aws-threat-detection-rule-guardduty-detector-disabled-or-suspended/ - https://www.atomicredteam.io/atomic-red-team/atomics/T156001#atomic-test-46---aws---guardduty-suspension-or-deletion author: suktech24 date: 2025-11-27 tags: - attack.defense-impairment - attack.t1685 - attack.t1685.002 logsource: product: aws service: cloudtrail detection: selection_event_source: eventSource: guardduty.amazonaws.com selection_action_delete: eventName: DeleteDetector selection_action_update: eventName: UpdateDetector requestParameters.enable: 'false' selection_status_success: errorCode: Success selection_status_null: errorCode: null condition: selection_event_source and 1 of selection_action_* and 1 of selection_status_* falsepositives: - Legitimate detector deletion by an admin (e.g., during account decommissioning). - Temporary disablement for troubleshooting (verify via change management tickets). - Automated deployment tools (e.g. Terraform) managing GuardDuty state. level: high