Sigma rule: APT40 Dropbox Tool User Agent

A detection rule from the SigmaHQ repository, shown as its author published it. Dataset version ref-6dcec8c76f30, updated 2023-05-18T00:00:00.000Z.

Rule

Title: APT40 Dropbox Tool User Agent
Status: test
Level: high
Author: Thomas Patzke
Date: 2019-11-12
Modified: 2023-05-18
File: rules-emerging-threats/2019/TA/APT40/proxy_apt_apt40_dropbox_tool_ua.yml
Commit: ccbb0369507f796db0b0ae6854c8a2be471b9d84

Detects suspicious user agent string of APT40 Dropbox tool

Log source

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

False positives (as the rule lists them)

Old browsers

MITRE ATT&CK ids this rule names

References

Internal research from Florian Roth

Read on 2026-11-03T00:58:21.399Z under licence sigma-drl-1.1@d5f4c36a from https://github.com/SigmaHQ/sigma/blob/ccbb0369507f796db0b0ae6854c8a2be471b9d84/rules-emerging-threats/2019/TA/APT40/proxy_apt_apt40_dropbox_tool_ua.yml

Sources and licences

SigmaHQ
"APT40 Dropbox Tool User Agent" by Thomas Patzke (SigmaHQ). Rule: https://github.com/SigmaHQ/sigma/blob/ccbb0369507f796db0b0ae6854c8a2be471b9d84/rules-emerging-threats/2019/TA/APT40/proxy_apt_apt40_dropbox_tool_ua.yml.
Licensed under the Detection Rule License (DRL) 1.1: https://github.com/SigmaHQ/Detection-Rule-License
Detection Rule License (DRL) 1.1

Cite this page

Dragons Eye Ransomware Tracker, "Sigma rule: APT40 Dropbox Tool User Agent",
entity page, dataset version ref-6dcec8c76f30, updated 2023-05-18T00:00:00.000Z,
https://ransomware-tracker.com/detections/sigma/5ba715b6-71b7-44fd-8245-f66893e81b3d (accessed 2026-11-03).
Underlying source: SigmaHQ rule 5ba715b6-71b7-44fd-8245-f66893e81b3d, commit ccbb0369507f796db0b0ae6854c8a2be471b9d84.

Pages change. The dataset version identifies the data, but no archive of old versions is kept, so this citation cannot be replayed later.