Microsoft Teams Sensitive File Access By Uncommon Applications

testmedium

log source: windows · file_accessauthor @SerkinValerydate 2024-07-22

description

What this is, in brief.

Detects file access attempts to sensitive Microsoft teams files (leveldb, cookies) by an uncommon process.

rule source (YAML)

title: Microsoft Teams Sensitive File Access By Uncommon Applications
id: 65744385-8541-44a6-8630-ffc824d7d4cc
status: test
description: |
    Detects file access attempts to sensitive Microsoft teams files (leveldb, cookies) by an uncommon process.
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
author: '@SerkinValery'
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:
        # Note: its best to filter the full path to avoid false negatives
        Image|endswith: '\Microsoft\Teams\current\Teams.exe'
    condition: selection and not 1 of filter_main_*
falsepositives:
    - Unknown
level: medium

detects techniques (1)

ATT&CK techniques this enables or maps to.

T1528Steal Application Access Token

references

External citations — patches, advisories, analysis.