Suspicious Teams Application Related ObjectAcess Event — Sigma Rule

Rule metadata and linked tags

Author: @SerkinValery. Source status: test; severity: high. Source dates: 2022-09-16 / not supplied.

{
  "product": "windows",
  "service": "security"
}

Pinned original Sigma rule · Detection Rule License 1.1

Source SHA-256: 2249d34fa404582464a43a7599048194e8f8af52ed560792d24bfb5f212458c7

Detection logic

Original source YAML. Source-tag agreement is not proof of complete semantic coverage. This rule has not been compiled for a SIEM backend or validated against live telemetry here.

title: Suspicious Teams Application Related ObjectAcess Event
id: 25cde13e-8e20-4c29-b949-4e795b76f16f
status: test
description: Detects an access to authentication tokens and accounts of Microsoft Teams desktop application.
references:
    - https://www.bleepingcomputer.com/news/security/microsoft-teams-stores-auth-tokens-as-cleartext-in-windows-linux-macs/
    - https://www.vectra.ai/blogpost/undermining-microsoft-teams-security-by-mining-tokens
author: '@SerkinValery'
date: 2022-09-16
tags:
    - attack.credential-access
    - attack.t1528
logsource:
    product: windows
    service: security
detection:
    selection:
        EventID: 4663
        ObjectName|contains:
            - '\Microsoft\Teams\Cookies'
            - '\Microsoft\Teams\Local Storage\leveldb'
    filter:
        ProcessName|contains: '\Microsoft\Teams\current\Teams.exe'
    condition: selection and not filter
falsepositives:
    - Unknown
level: high

Original YAML and metadata in JSON

False positives

• Unknown

Source references

• https://www.bleepingcomputer.com/news/security/microsoft-teams-stores-auth-tokens-as-cleartext-in-windows-linux-macs/
• https://www.vectra.ai/blogpost/undermining-microsoft-teams-security-by-mining-tokens