Cisco Isovalent - Curl Execution With Insecure Flags

SPLUNK detection rule by Bhavin Patel, Splunk · Apache-2.0

The following analytic detects the execution of curl commands with insecure flags within the Cisco Isovalent environment. It identifies this activity by monitoring process execution logs for curl commands that use the -k or --insecure flags. This behavior is significant for a SOC as it could allow an attacker to bypass SSL/TLS verification, potentially exposing the Kubernetes infrastructure to man-in-the-middle attacks. If confirmed malicious, this activity could lead to data interception, service disruptions, or unauthorized access to sensitive information.

name: Cisco Isovalent - Curl Execution With Insecure Flags
id: c16c4899-d3f7-461b-92c2-cc0ef5758855
version: 5
creation_date: '2026-01-05'
modification_date: '2026-05-13'
author: Bhavin Patel, Splunk
status: production
type: Anomaly
description: The following analytic detects the execution of curl commands with insecure flags within the Cisco Isovalent environment. It identifies this activity by monitoring process execution logs for curl commands that use the -k or --insecure flags. This behavior is significant for a SOC as it could allow an attacker to bypass SSL/TLS verification, potentially exposing the Kubernetes infrastructure to man-in-the-middle attacks. If confirmed malicious, this activity could lead to data interception, service disruptions, or unauthorized access to sensitive  information.
data_source:
    - Cisco Isovalent Process Exec
search: |
    `cisco_isovalent_process_exec`  process_name="curl"
    | regex process="(?i)(?<!\w)-(?:[a-z]*k[a-z]*|-(insecure|proxy-insecure|doh-insecure))"
    | stats count min(_time) as firstTime max(_time) as lastTime values(process) as process
        by cluster_name pod_name parent_process_name process_name process_exec process_id node_name
    | `security_content_ctime(firstTime)`
    | `security_content_ctime(lastTime)`
    | `cisco_isovalent___curl_execution_with_insecure_flags_filter`
how_to_implement: The detection is based on process execution data generated by Cisco Isovalent Runtime Security. Ensure that Isovalent Runtime Security is deployed and configured in your Kubernetes environment to emit process_exec events. Configure the Cisco Security Cloud TA to collect these logs via HTTP Event Collector (HEC) and normalize them into the Splunk Common Information Model. This integration ensures that all relevant pod, container, and process activity is captured for monitoring and detection of suspicious behavior.
known_false_positives: This activity may be triggered by legitimate administrative scripts, container images, or third-party operators that use cron for scheduled tasks, so please investigate the alert in context to rule out benign operations.
references:
    - https://rawcode7.medium.com/understanding-the-kubernetes-attack-surface-9a48ebcb6bc4
    - https://www.tutorialworks.com/kubernetes-curl/
drilldown_searches:
    - name: View the detection results for - "$pod_name$"
      search: '%original_detection_search% | search pod_name = "$pod_name$"'
      earliest_offset: $info_min_time$
      latest_offset: $info_max_time$
    - name: View risk events for the last 7 days for - "$pod_name$"
      search: '| from datamodel Risk.All_Risk | search normalized_risk_object IN ("$pod_name$") | 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"
intermediate_findings:
    entities:
        - field: pod_name
          type: system
          score: 20
          message: A curl execution with insecure flags has been detected on pod_name [$pod_name$] in the cluster [$cluster_name$]
threat_objects:
    - field: process_name
      type: process_name
analytic_story:
    - Cisco Isovalent Suspicious Activity
asset_type: Endpoint
atomic_guid:
    - 7e2ad0db-1efa-4af2-a77c-bc6e87d7b3f3
mitre_attack_id:
    - T1105
product:
    - Splunk Enterprise
    - Splunk Enterprise Security
    - Splunk Cloud
category: endpoint
security_domain: endpoint
tests:
    - name: True Positive Test
      attack_data:
        - data: https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/cisco_isovalent/cisco_isovalent.log
          source: not_applicable
          sourcetype: cisco:isovalent:processExec
      test_type: unit

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08515999-fd8f-4300-aa8b-4d49f81bb487

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Executable code, not a declarative rule

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