Linux Possible Nimbuspwn Privilege Escalation

SPLUNK detection rule by Raven Tait, Splunk · Apache-2.0

The following analytic detects directory traversal attempts associated with Nimbuspwn, a Linux privilege escalation vulnerability affecting the networkd-dispatcher service. Nimbuspwn exploits weaknesses in the networkd-dispatcher service to traverse directories and execute arbitrary code with elevated privileges. If confirmed malicious, this activity could allow an attacker to escalate privileges to root, potentially leading to full system compromise, persistent unauthorized access, and the ability to deploy additional malicious payloads.

name: Linux Possible Nimbuspwn Privilege Escalation
id: 24a540b7-6eec-4972-ad85-1f2232f9a849
version: 1
creation_date: '2026-07-08'
modification_date: '2026-07-08'
author: Raven Tait, Splunk
status: production
type: TTP
description: |-
    The following analytic detects directory traversal attempts associated with Nimbuspwn, a Linux privilege escalation vulnerability affecting the networkd-dispatcher service.
    Nimbuspwn exploits weaknesses in the networkd-dispatcher service to traverse directories and execute arbitrary code with elevated privileges.
    If confirmed malicious, this activity could allow an attacker to escalate privileges to root, potentially leading to full system compromise, persistent unauthorized access, and the ability to deploy additional malicious payloads.
data_source:
    - Sysmon for Linux EventID 1
search: |-
    | tstats `security_content_summariesonly`
      count min(_time) as firstTime
            max(_time) as lastTime

    from datamodel=Endpoint.Processes where

    Processes.process="*networkd-dispatcher*"
    Processes.process="*../*"

    by Processes.process Processes.vendor_product Processes.user_id
       Processes.process_hash Processes.parent_process_name Processes.parent_process_exec
       Processes.action Processes.dest Processes.process_current_directory Processes.process_path
       Processes.process_integrity_level Processes.original_file_name Processes.parent_process
       Processes.parent_process_path Processes.parent_process_guid Processes.parent_process_id
       Processes.process_guid Processes.process_id Processes.user Processes.process_name

    | `drop_dm_object_name(Processes)`
    | `security_content_ctime(firstTime)`
    | `security_content_ctime(lastTime)`
    | `linux_possible_nimbuspwn_privilege_escalation_filter`
how_to_implement: The detection is based on data that originates from Endpoint Detection and Response (EDR) agents. These agents are designed to provide security-related telemetry from the endpoints where the agent is installed. To implement this search, you must ingest logs that contain the process GUID, process name, and parent process. Additionally, you must ingest complete command-line executions. These logs must be processed using the appropriate Splunk Technology Add-ons that are specific to the EDR product. The logs must also be mapped to the `Processes` node of the `Endpoint` data model. Use the Splunk Common Information Model (CIM) to normalize the field names and speed up the data modeling process.
known_false_positives: Legitimate system processes or administrative scripts that traverse directories in a similar pattern may trigger this detection. Filter based on known administrative activity and verified system processes.
references:
    - https://www.microsoft.com/security/blog/2022/04/26/microsoft-finds-new-elevation-of-privilege-linux-vulnerability-nimbuspwn/
drilldown_searches:
    - earliest_offset: $info_min_time$
      latest_offset: $info_max_time$
      name: View the detection results for - "$user$" and "$dest$"
      search: '%original_detection_search% | search  user = "$user$" dest = "$dest$"'
    - name: View risk events for the last 7 days for - "$user$" and "$dest$"
      search: '| from datamodel Risk.All_Risk | search normalized_risk_object IN ("$user$", "$dest$") | stats count min(_time) as firstTime max(_time) as lastTime values(search_name) as "Search Name" values(risk_message) as "Risk Message" values(analyticstories) as "Analytic Stories" values(annotations._all) as "Annotations" values(annotations.mitre_attack.mitre_tactic) as "ATT&CK Tactics" by normalized_risk_object | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)`'
      earliest_offset: 7d
      latest_offset: '0'
finding:
    title: Possible Nimbuspwn privilege escalation via [$process$] by [$user$] on [$dest$]
    entity:
        field: dest
        type: system
        score: 50
threat_objects:
    - field: parent_process_name
      type: parent_process_name
    - field: process_name
      type: process_name
    - field: process
      type: process
analytic_story:
    - Linux Privilege Escalation
    - Linux Persistence Techniques
    - Linux Post-Exploitation
asset_type: Endpoint
cve:
    - CVE-2022-29799
    - CVE-2022-29800
mitre_attack_id:
    - T1068
product:
    - Splunk Enterprise
    - Splunk Enterprise Security
    - Splunk Cloud
category: endpoint
security_domain: endpoint
tests:
    - name: True Positive Test
      test_type: unit
      attack_data:
        - data: https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/attack_techniques/T1068/linux_possible_nimbuspwn_directory_traversal/snapattack_linux.log
          source: Syslog:Linux-Sysmon/Operational
          sourcetype: sysmon:linux

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