Detection rules › Sigma
Suspicious Dropbox API Usage
Detects an executable that isn't dropbox but communicates with the Dropbox API
MITRE ATT&CK coverage
| Tactic | Techniques |
|---|---|
| Command & Control | T1105 Ingress Tool Transfer |
| Exfiltration | T1567.002 Exfiltration Over Web Service: Exfiltration to Cloud Storage |
Event coverage
| Provider | Event | Title |
|---|---|---|
| Sysmon | Event ID 3 | Network connection |
Rule body yaml
title: Suspicious Dropbox API Usage
id: 25eabf56-22f0-4915-a1ed-056b8dae0a68
status: test
description: Detects an executable that isn't dropbox but communicates with the Dropbox API
references:
- https://app.any.run/tasks/7e906adc-9d11-447f-8641-5f40375ecebb
- https://www.zscaler.com/blogs/security-research/new-espionage-attack-molerats-apt-targeting-users-middle-east
author: Florian Roth (Nextron Systems)
date: 2022-04-20
tags:
- attack.command-and-control
- attack.exfiltration
- attack.t1105
- attack.t1567.002
logsource:
category: network_connection
product: windows
detection:
selection:
Initiated: 'true'
DestinationHostname|endswith:
- 'api.dropboxapi.com'
- 'content.dropboxapi.com'
filter_main_legit_dropbox:
# Note: It's better to add a specific path to the exact location(s) where dropbox is installed
Image|contains: '\Dropbox'
condition: selection and not 1 of filter_main_*
falsepositives:
- Legitimate use of the API with a tool that the author wasn't aware of
level: high
Stages and Predicates
Stage 0: condition
selection and not 1 of filter_main_*Stage 1: selection
selection:
Initiated: 'true'
DestinationHostname|endswith:
- 'api.dropboxapi.com'
- 'content.dropboxapi.com'
Stage 2: not filter_main_legit_dropbox
filter_main_legit_dropbox:
Image|contains: '\Dropbox'
Exclusions
Top-level NOT(...) conjuncts: predicates this rule actively suppresses.
| Field | Kind | Excluded values |
|---|---|---|
Image | match | \Dropbox |
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.
| Field | Kind | Values |
|---|---|---|
DestinationHostname | ends_with |
|
Initiated | eq |
|