Remote File Download via Desktopimgdownldr Utility

Identifies the desktopimgdownldr utility being used to download a remote file. An adversary may use desktopimgdownldr to download arbitrary files as an alternative to certutil.

Rule type: eql

Rule indices:

winlogbeat-*
logs-endpoint.events.*
logs-windows.*

Severity: medium

Risk score: 47

Runs every: 5 minutes

Searches indices from: now-9m (Date Math format, see also Additional look-back time)

Maximum alerts per execution: 100

References:

https://labs.sentinelone.com/living-off-windows-land-a-new-native-file-downldr/

Tags:

Elastic
Host
Windows
Threat Detection
Command and Control

Version: 5 (version history)

Added (Elastic Stack release): 7.10.0

Last modified (Elastic Stack release): 7.13.0

Rule authors: Elastic

Rule license: Elastic License v2

Rule query

edit

process where event.type in ("start", "process_started") and
(process.name : "desktopimgdownldr.exe" or
process.pe.original_file_name == "desktopimgdownldr.exe") and
process.args : "/lockscreenurl:http*"

Threat mapping

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Framework: MITRE ATT&CK^TM

Tactic:
- Name: Command and Control
- ID: TA0011
- Reference URL: https://attack.mitre.org/tactics/TA0011/
Technique:
- Name: Ingress Tool Transfer
- ID: T1105
- Reference URL: https://attack.mitre.org/techniques/T1105/

Rule version history

edit

Version 5 (7.13.0 release)

Updated query, changed from:

event.category:process and event.type:(start or process_started) and
(process.name:desktopimgdownldr.exe or
process.pe.original_file_name:desktopimgdownldr.exe) and
process.args:/lockscreenurl\:http*

Version 4 (7.12.0 release)

Formatting only

Version 3 (7.11.2 release)

Formatting only

Version 2 (7.11.0 release)

Updated query, changed from:

event.category:process and event.type:(start or process_started) and
(process.name:desktopimgdownldr.exe or
process.pe.original_file_name:desktopimgdownldr.exe or
winlog.event_data.OriginalFileName:desktopimgdownldr.exe) and
process.args:/lockscreenurl\:http*

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