Windows: Uncommon Process Access to Microsoft Teams Cookies or Local Storage leveldb

Alerts on access to Teams Cookies or leveldb files by processes other than Teams.exe on Windows.

FreeReviewedSigma · Medium · v2

Product: windows
Category: file_access
Author: @SerkinValery (SigmaHQ), DRL 1.1
Published: 2024-07-22
Updated: 2026-07-31

ATT&CK techniques

Cred Access

Recon
Resource Dev
Initial Access
Execution
Persistence
Priv Esc
Defense Evasion
Cred Access
- T1528Steal Application Access Token
Discovery
Lateral Movement
Collection
C2
Exfiltration
Impact

What it detects

This rule flags attempts by a process other than Teams.exe to access sensitive Microsoft Teams data locations, specifically Cookies and Local Storage leveldb files. Attackers may target these files to obtain authentication material or session-related data. The detection relies on Windows file access telemetry that includes the accessed path (FileName) and the calling process image (Image).

Reporting behind it

Related detections9 linkedT1528 — drag to rearrange

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Possible Illicit Consent Grant to OAuth Application via Azure AD

Suspicious Device Code Authentication via Microsoft Authentication Broker

Windows: Uncommon Process Access to Microsoft Teams Cookies or Local Storage leveldb

Pivot detection · T1528 · 9 related

Changelog

v2
Candidate ingested via manual entry.2026-07-31
v1
No changelog recorded for this version.2026-07-30

Detection content is published as a reviewed draft. Tune thresholds and exclusions against your own telemetry before enabling this rule for alerting.

windows-uncommon-processes-accessing-microsoft-teams-cookies-or-local-storage-le-65744385

title: "Windows: Uncommon Process Access to Microsoft Teams Cookies or Local Storage leveldb"
id: 5131fa5f-cf41-4703-92a8-5a734972722f
status: test
description: This rule flags attempts by a process other than Teams.exe to access sensitive Microsoft Teams data locations, specifically Cookies and Local Storage leveldb files. Attackers may target these files to obtain authentication material or session-related data. The detection relies on Windows file access telemetry that includes the accessed path (FileName) and the calling process image (Image).
references:
  - https://www.bleepingcomputer.com/news/security/microsoft-teams-stores-auth-tokens-as-cleartext-in-windows-linux-macs/
  - https://www.vectra.ai/blog/undermining-microsoft-teams-security-by-mining-tokens
  - https://github.com/SigmaHQ/sigma/blob/master/rules/windows/file/file_access/file_access_win_teams_sensitive_files.yml
author: "@SerkinValery, Huntrule Team"
date: 2024-07-22
tags:
  - attack.credential-access
  - attack.t1528
logsource:
  product: windows
  category: file_access
  definition: "Requirements: Microsoft-Windows-Kernel-File ETW provider"
detection:
  selection:
    FileName|contains:
      - \Microsoft\Teams\Cookies
      - \Microsoft\Teams\Local Storage\leveldb
  filter_main_legit_location:
    Image|endswith: \Microsoft\Teams\current\Teams.exe
  condition: selection and not 1 of filter_main_*
falsepositives:
  - Unknown
level: medium
license: DRL-1.1
related:
  - id: 65744385-8541-44a6-8630-ffc824d7d4cc
    type: derived

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