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Detection rules › Sigma

APT40 Dropbox Tool User Agent

Status
test
Severity
high
Log source
category proxy
Author
Thomas Patzke
Source
github.com/SigmaHQ/sigma

Detects suspicious user agent string of APT40 Dropbox tool

Known false positives

  • Old browsers

MITRE ATT&CK coverage

TacticTechniques
Command & Control
Exfiltration

Rule body

title: APT40 Dropbox Tool User Agent
id: 5ba715b6-71b7-44fd-8245-f66893e81b3d
status: test
description: Detects suspicious user agent string of APT40 Dropbox tool
references:
    - Internal research from Florian Roth
author: Thomas Patzke
date: 2019-11-12
modified: 2023-05-18
tags:
    - attack.command-and-control
    - attack.t1071.001
    - attack.exfiltration
    - attack.t1567.002
    - detection.emerging-threats
logsource:
    category: proxy
detection:
    selection:
        c-useragent: 'Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/36.0.1985.143 Safari/537.36'
        cs-host: 'api.dropbox.com'
    condition: selection
falsepositives:
    - Old browsers
level: high

Stages and Predicates

Stage 0: condition

selection

Stage 1: selection

selection:
    c-useragent: 'Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/36.0.1985.143 Safari/537.36'
    cs-host: 'api.dropbox.com'

Indicators

These rows show field, operator, and value matches.

FieldKindValuesSearch
c-useragenteq
  • Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/36.0.1985.143 Safari/537.36
field:"c-useragent" kind:eq value:"Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/36.0.1985.143 Safari/537.36"
cs-hosteq
  • api.dropbox.com
field:"cs-host" kind:eq value:"api.dropbox.com"