Kubernetes Anomalous Outbound Network Activity from Process

name: Kubernetes Anomalous Outbound Network Activity from Process
id: dd6afee6-e0a3-4028-a089-f47dd2842c22
version: 8
date: '2026-03-10'
author: Matthew Moore, Splunk
status: experimental
type: Anomaly
description: The following analytic identifies anomalously high outbound network activity from processes running within containerized workloads in a Kubernetes environment. It leverages Network Performance Monitoring metrics collected via an OTEL collector and pulled from Splunk Observability Cloud. The detection compares recent network metrics (tcp.bytes, tcp.new_sockets, tcp.packets, udp.bytes, udp.packets) over the last hour with the average metrics over the past 30 days. This activity is significant as it may indicate data exfiltration, process modification, or container compromise. If confirmed malicious, it could lead to unauthorized data exfiltration, communication with malicious entities, or further attacks within the containerized environment.
data_source: []
search: "| mstats avg(tcp.*) as tcp.* avg(udp.*) as udp.* where `kubernetes_metrics` AND earliest=-1h by k8s.cluster.name source.workload.name source.process.name  span=10s | eval key='source.workload.name' + \":\" + 'source.process.name' | join type=left key [ mstats avg(tcp.*) as avg_tcp.* avg(udp.*) as avg_udp.* stdev(tcp.*) as stdev_tcp.* avg(udp.*) as stdev_udp.* where `kubernetes_metrics` AND earliest=-30d latest=-1h by source.workload.name source.process.name | eval key='source.workload.name' + \":\" + 'source.process.name' ] | eval anomalies = \"\" | foreach stdev_* [ eval anomalies =if( '<<MATCHSTR>>' > ('avg_<<MATCHSTR>>' + 3 * 'stdev_<<MATCHSTR>>'), anomalies + \"<<MATCHSTR>> higher than average by \" + tostring(round(('<<MATCHSTR>>' - 'avg_<<MATCHSTR>>')/'stdev_<<MATCHSTR>>' ,2)) + \" Standard Deviations. <<MATCHSTR>>=\" + tostring('<<MATCHSTR>>') + \" avg_<<MATCHSTR>>=\" + tostring('avg_<<MATCHSTR>>') + \" 'stdev_<<MATCHSTR>>'=\" + tostring('stdev_<<MATCHSTR>>') + \", \" , anomalies) ] | fillnull | eval anomalies = split(replace(anomalies, \",\\s$$$$\", \"\") ,\", \") | where anomalies!=\"\" | stats count(anomalies) as count values(anomalies) as anomalies by k8s.cluster.name source.workload.name source.process.name | where count > 5 | rename k8s.cluster.name as host | `kubernetes_anomalous_outbound_network_activity_from_process_filter`"
how_to_implement: "To gather NPM metrics the Open Telemetry to the Kubernetes Cluster and enable Network Performance Monitoring according to instructions found in Splunk Docs https://help.splunk.com/en/splunk-observability-cloud/monitor-infrastructure/network-explorer/set-up-network-explorer-in-kubernetes#network-explorer-setup In order to access those metrics from within Splunk Enterprise and ES, the Splunk Infrastructure Monitoring add-on must be installed and configured on a Splunk Search Head.  Once installed, first configure the add-on with your O11y Cloud Org ID and Access Token. Lastly set up the add-on to ingest metrics from O11y cloud using the following settings, and any other settings left at default:\n* Name sim_npm_metrics_to_metrics_index\n * Metric Resolution 10000"
known_false_positives: No false positives have been identified at this time.
references:
    - https://github.com/signalfx/splunk-otel-collector-chart
rba:
    message: Kubernetes Anomalous Outbound Network Activity from Process in kubernetes cluster $host$
    risk_objects:
        - field: host
          type: system
          score: 20
    threat_objects: []
tags:
    analytic_story:
        - Abnormal Kubernetes Behavior using Splunk Infrastructure Monitoring
    asset_type: Kubernetes
    mitre_attack_id:
        - T1204
    product:
        - Splunk Enterprise
        - Splunk Enterprise Security
        - Splunk Cloud
    security_domain: network