Sigma rule: DEWMODE Webshell Access

A detection rule from the SigmaHQ repository, shown as its author published it. Dataset version ref-848ebf2c99a7, updated 2023-01-02T00:00:00.000Z.

Rule

Title
DEWMODE Webshell Access
Status
test
Level
high
Author
Florian Roth (Nextron Systems)
Date
2021-02-22
Modified
2023-01-02
File
rules-emerging-threats/2021/TA/UNC2546/web_unc2546_dewmode_php_webshell.yml
Commit
ccbb0369507f796db0b0ae6854c8a2be471b9d84

Detects access to DEWMODE webshell as described in FIREEYE report

Log source

category
webserver

Detection

selection1:
    cs-uri-query|contains|all:
        - '?dwn='
        - '&fn='
        - '.html?'
selection2:
    cs-uri-query|contains|all:
        - '&dwn='
        - '?fn='
        - '.html?'
condition: 1 of selection*

False positives (as the rule lists them)

  • Unknown

Tags

  • attack.persistence
  • attack.t1505.003
  • detection.emerging-threats

MITRE ATT&CK ids this rule names

References

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/2021/TA/UNC2546/web_unc2546_dewmode_php_webshell.yml

Sources and licences

  • SigmaHQ

    "DEWMODE Webshell Access" by Florian Roth (Nextron Systems) (SigmaHQ). Rule: https://github.com/SigmaHQ/sigma/blob/ccbb0369507f796db0b0ae6854c8a2be471b9d84/rules-emerging-threats/2021/TA/UNC2546/web_unc2546_dewmode_php_webshell.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: DEWMODE Webshell Access",
entity page, dataset version ref-848ebf2c99a7, updated 2023-01-02T00:00:00.000Z,
https://ransomware-tracker.com/detections/sigma/fdf96c90-42d5-4406-8a9c-14a2c9a016b5 (accessed 2026-11-03).
Underlying source: SigmaHQ rule fdf96c90-42d5-4406-8a9c-14a2c9a016b5, 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.