New ActiveSyncAllowedDeviceID Added via PowerShell
editNew ActiveSyncAllowedDeviceID Added via PowerShell
editIdentifies the use of the Exchange PowerShell cmdlet Set-CASMailbox to add a new ActiveSync allowed device. Adversaries may target user email to collect sensitive information.
Rule type: eql
Rule indices:
- logs-endpoint.events.*
- winlogbeat-*
- logs-windows.*
Severity: medium
Risk score: 47
Runs every: 5m
Searches indices from: now-9m (Date Math format, see also Additional look-back time)
Maximum alerts per execution: 100
References:
Tags:
- Elastic
- Host
- Windows
- Threat Detection
- Persistence
Version: 7
Rule authors:
- Elastic
Rule license: Elastic License v2
Investigation guide
edit## 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 query
editprocess where event.type in ("start", "process_started") and
process.name: ("powershell.exe", "pwsh.exe", "powershell_ise.exe") and process.args : "Set-CASMailbox*ActiveSyncAllowedDeviceIDs*"
Framework: MITRE ATT&CKTM
-
Tactic:
- Name: Persistence
- ID: TA0003
- Reference URL: https://attack.mitre.org/tactics/TA0003/
-
Technique:
- Name: Account Manipulation
- ID: T1098
- Reference URL: https://attack.mitre.org/techniques/T1098/
-
Sub-technique:
- Name: Exchange Email Delegate Permissions
- ID: T1098.002
- Reference URL: https://attack.mitre.org/techniques/T1098/002/