IMPORTANT: No additional bug fixes or documentation updates
will be released for this version. For the latest information, see the
current release documentation.
Screensaver Plist File Modified by Unexpected Processedit
Identifies when a screensaver plist file is modified by an unexpected process. An adversary can maintain persistence on a macOS endpoint by creating a malicious screensaver (.saver) file and configuring the screensaver plist file to execute code each time the screensaver is activated.
Rule type: eql
Rule indices:
- auditbeat-*
- logs-endpoint.events.*
Severity: medium
Risk score: 47
Runs every: 5 minutes
Searches indices from: now-9m (Date Math format, see also Additional look-back time)
Maximum alerts per execution: 100
References:
Tags:
- Elastic
- Host
- macOS
- Threat Detection
- Persistence
Version: 2 (version history)
Added (Elastic Stack release): 7.16.0
Last modified (Elastic Stack release): 8.2.0
Rule authors: Elastic
Rule license: Elastic License v2
Investigation guideedit
## Triage and analysis - Analyze the plist file modification event to identify whether the change was expected or not - Investigate the process that modified the plist file for malicious code or other suspicious behavior - Identify if any suspicious or known malicious screensaver (.saver) files were recently written to or modified on the host ## Config If enabling an EQL rule on a non-elastic-agent index (such as beats) for versions <8.2, events will not define `event.ingested` and default fallback for EQL rules was not added until 8.2, so you will need to add a custom pipeline to populate `event.ingested` to @timestamp for this rule to work.
Rule queryedit
file where event.type != "deletion" and file.name: "com.apple.screensaver.*.plist" and file.path : ( "/Users/*/Library/Preferences/ByHost/*", "/Library/Managed Preferences/*", "/System/Library/Preferences/*" ) and /* Filter OS processes modifying screensaver plist files */ not process.executable : ( "/usr/sbin/cfprefsd", "/usr/libexec/xpcproxy", "/System/Library/CoreServices/ManagedClie nt.app/Contents/Resources/MCXCompositor", "/System/Library/CoreSer vices/ManagedClient.app/Contents/MacOS/ManagedClient" )
Threat mappingedit
Framework: MITRE ATT&CKTM
-
Tactic:
- Name: Persistence
- ID: TA0003
- Reference URL: https://attack.mitre.org/tactics/TA0003/
-
Technique:
- Name: Event Triggered Execution
- ID: T1546
- Reference URL: https://attack.mitre.org/techniques/T1546/
Rule version historyedit
- Version 2 (8.2.0 release)
-
- Formatting only