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Detection rules › Sigma

Primary Refresh Token Access Attempt

Status
test
Severity
high
Log source
product azure, service riskdetection
Author
Mark Morowczynski '@markmorow', Gloria Lee, '@gleeiamglo'
Source
github.com/SigmaHQ/sigma

Indicates access attempt to the PRT resource which can be used to move laterally into an organization or perform credential theft

MITRE ATT&CK coverage

TacticTechniques
Credential AccessT1528 Steal Application Access Token

Rule body yaml

title: Primary Refresh Token Access Attempt
id: a84fc3b1-c9ce-4125-8e74-bdcdb24021f1
status: test
description: Indicates access attempt to the PRT resource which can be used to move laterally into an organization or perform credential theft
references:
    - https://learn.microsoft.com/en-us/entra/id-protection/concept-identity-protection-risks#possible-attempt-to-access-primary-refresh-token-prt
    - https://learn.microsoft.com/en-us/entra/architecture/security-operations-user-accounts#unusual-sign-ins
author: Mark Morowczynski '@markmorow', Gloria Lee, '@gleeiamglo'
date: 2023-09-07
tags:
    - attack.t1528
    - attack.credential-access
logsource:
    product: azure
    service: riskdetection
detection:
    selection:
        riskEventType: 'attemptedPrtAccess'
    condition: selection
falsepositives:
    - This detection is low-volume and is seen infrequently in most organizations. When this detection appears it's high risk, and users should be remediated.
level: high

Stages and Predicates

Stage 0: condition

selection

Stage 1: selection

selection:
    riskEventType: 'attemptedPrtAccess'

Indicators

Each row is a field, operator, and value that the rule matches. The corpus column counts how many other rules in the catalog look for the same combination: high numbers point to widely-used, community-vetted indicators. Blank or 1 shows that the indicator is specific to this rule.

FieldKindValues
riskEventTypeeq
  • attemptedPrtAccess