This analytic searches for a registry modification that enables the use of the at.exe or wmi Win32_ScheduledJob command to add scheduled tasks on a Windows endpoint. Specifically, it looks for the creation of a new DWORD value named "EnableAt" in the following registry path: "HKLM:\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Schedule\Configuration". If this value is set to 1, it enables the at.exe and wmi Win32_ScheduledJob commands to schedule tasks on the system. Detecting this registry modification is important because it may indicate that an attacker has enabled the ability to add scheduled tasks to the system, which can be used to execute malicious code at specific times or intervals.
- Type: Anomaly
- Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud
- Datamodel: Endpoint
- Last Updated: 2023-03-27
- Author: Michael Haag, Splunk
- ID: 12c80db8-ef62-4456-92df-b23e1b3219f6
Kill Chain Phase
- CIS 10
1 2 3 4 5 6 | tstats `security_content_summariesonly` count values(Registry.registry_key_name) as registry_key_name values(Registry.registry_path) as registry_path min(_time) as firstTime max(_time) as lastTime from datamodel=Endpoint.Registry where Registry.registry_path="*\\CurrentVersion\\Schedule\\Configuration*" Registry.registry_value_name=EnableAt by Registry.dest, Registry.user, Registry.registry_value_name, Registry.registry_value_type | `security_content_ctime(lastTime)` | `security_content_ctime(firstTime)` | `drop_dm_object_name(Registry)` | `windows_enable_win32_scheduledjob_via_registry_filter`
The SPL above uses the following Macros:
windows_enable_win32_scheduledjob_via_registry_filter is a empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.
List of fields required to use this analytic.
How To Implement
To successfully implement this search you need to be ingesting information on process that include the name of the process responsible for the changes from your endpoints into the
Endpoint datamodel in the
Registry node. In addition, confirm the latest CIM App 4.20 or higher is installed and the latest TA for the endpoint product.
Known False Positives
In some cases, an automated script or system may enable this setting continuously, leading to false positives. To avoid such situations, it is recommended to monitor the frequency and context of the registry modification and modify or filter the detection rules as needed. This can help to reduce the number of false positives and ensure that only genuine threats are identified. Additionally, it is important to investigate any detected instances of this modification and analyze them in the broader context of the system and network to determine if further action is necessary.
Associated Analytic Story
|25.0||50||50||A process has modified the schedule task registry value - EnableAt - on endpoint $dest$ by user $user$.|
The Risk Score is calculated by the following formula: Risk Score = (Impact * Confidence/100). Initial Confidence and Impact is set by the analytic author.
source | version: 1