Detection: MacOS - Re-opened Applications

Description

The following analytic identifies processes referencing plist files that determine which applications are re-opened when a user reboots their MacOS machine. It leverages data from Endpoint Detection and Response (EDR) agents, focusing on process names and parent processes related to "com.apple.loginwindow." This activity is significant because it can indicate attempts to persist across reboots, a common tactic used by attackers to maintain access. If confirmed malicious, this could allow an attacker to execute code or maintain persistence on the affected system, potentially leading to further compromise.

Search

 1
 2| tstats `security_content_summariesonly` count values(Processes.process) as process values(Processes.parent_process) as parent_process min(_time) as firstTime max(_time) as lastTime FROM datamodel=Endpoint.Processes
 3  WHERE Processes.process="*com.apple.loginwindow*"
 4  BY Processes.user Processes.process_name Processes.parent_process_name
 5     Processes.dest
 6
 7| `drop_dm_object_name(Processes)`
 8
 9| `security_content_ctime(firstTime)`
10
11| `security_content_ctime(lastTime)`
12
13| `macos___re_opened_applications_filter`

Data Source

Name	Platform	Sourcetype	Source
Sysmon EventID 1	Windows	'XmlWinEventLog'	'XmlWinEventLog:Microsoft-Windows-Sysmon/Operational'

Macros Used

Annotations

Default Configuration

This detection is configured by default in Splunk Enterprise Security to run with the following settings:

Implementation

The detection is based on data that originates from Endpoint Detection and Response (EDR) agents. These agents are designed to provide security-related telemetry from the endpoints where the agent is installed. To implement this search, you must ingest logs that contain the process GUID, process name, and parent process. Additionally, you must ingest complete command-line executions. These logs must be processed using the appropriate Splunk Technology Add-ons that are specific to the EDR product. The logs must also be mapped to the Processes node of the Endpoint data model. Use the Splunk Common Information Model (CIM) to normalize the field names and speed up the data modeling process.

Known False Positives

At this stage, there are no known false positives. During testing, no process events referring the com.apple.loginwindow.plist files were observed during normal operation of re-opening applications on reboot. Therefore, it can be assumed that any occurrences of this in the process events would be worth investigating. In the event that the legitimate modification by the system of these files is in fact logged to the process log, then the process_name of that process can be added to an allow list.

Associated Analytic Story

No associated analytic story

Detection Testing

Replay any dataset to Splunk Enterprise by using our replay.py tool or the UI. Alternatively you can replay a dataset into a Splunk Attack Range

Source: GitHub |

Version: 9