Zeek: Detect WebDAV User-Agent with HTTP PUT to local or RFC1918 addresses

Flags Zeek HTTP PUT requests with a WebDAV User-Agent that target non-excluded network addresses.

FreeReviewedSigma · Low · v2

Product: zeek
Service: http
Author: Roberto Rodriguez (Cyb3rWard0g), OTR (Open Threat Research) (SigmaHQ), DRL 1.1
Published: 2020-05-02
Updated: 2026-07-31

ATT&CK techniques

Exfiltration

Recon
Resource Dev
Initial Access
Execution
Persistence
Priv Esc
Defense Evasion
Cred Access
Discovery
Lateral Movement
Collection
C2
Exfiltration
- T1048.003Exfiltration Over Unencrypted Non-C2 Protocol
Impact

What it detects

This rule flags HTTP requests where the User-Agent contains "WebDAV" and the HTTP method is PUT. Such traffic can indicate uploading or staging data on WebDAV-enabled network shares, which may be abused for data exfiltration or other unauthorized writes. It relies on Zeek HTTP telemetry fields for the request method, User-Agent, and destination IP, excluding common local and reserved ranges defined by the rule's IP filters.

Reporting behind it

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Zeek: Detect WebDAV User-Agent with HTTP PUT to local or RFC1918 addresses

Pivot detection · T1048.003 · 9 related

Changelog

v2
Candidate ingested via manual entry.2026-07-31
v1
No changelog recorded for this version.2026-07-30

Detection content is published as a reviewed draft. Tune thresholds and exclusions against your own telemetry before enabling this rule for alerting.

zeek-http-webdav-user-agent-with-put-method-to-local-network-705072a5

title: "Zeek: Detect WebDAV User-Agent with HTTP PUT to local or RFC1918 addresses"
id: 35a2cfa2-0113-4302-8137-88c27244d4c9
status: test
description: This rule flags HTTP requests where the User-Agent contains "WebDAV" and the HTTP method is PUT. Such traffic can indicate uploading or staging data on WebDAV-enabled network shares, which may be abused for data exfiltration or other unauthorized writes. It relies on Zeek HTTP telemetry fields for the request method, User-Agent, and destination IP, excluding common local and reserved ranges defined by the rule's IP filters.
references:
  - https://github.com/OTRF/detection-hackathon-apt29/issues/17
  - https://github.com/SigmaHQ/sigma/blob/master/rules/network/zeek/zeek_http_webdav_put_request.yml
author: Roberto Rodriguez (Cyb3rWard0g), OTR (Open Threat Research), Huntrule Team
date: 2020-05-02
modified: 2024-03-13
tags:
  - attack.exfiltration
  - attack.t1048.003
logsource:
  product: zeek
  service: http
detection:
  selection:
    user_agent|contains: WebDAV
    method: PUT
  filter:
    id.resp_h|cidr:
      - 10.0.0.0/8
      - 127.0.0.0/8
      - 172.16.0.0/12
      - 192.168.0.0/16
      - 169.254.0.0/16
  condition: selection and not filter
falsepositives:
  - Unknown
level: low
license: DRL-1.1
related:
  - id: 705072a5-bb6f-4ced-95b6-ecfa6602090b
    type: derived

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