Name:Linux Possible Nimbuspwn Privilege Escalation id:24a540b7-6eec-4972-ad85-1f2232f9a849 version:1 date:None 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
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' analytic_story:['Linux Privilege Escalation', 'Linux Persistence Techniques', 'Linux Post-Exploitation']
