Detection: Cisco Isovalent - Curl Execution With Insecure Flags

Updated Date: 2026-01-05 ID: c16c4899-d3f7-461b-92c2-cc0ef5758855 Author: Bhavin Patel, Splunk Type: Anomaly Product: Splunk Enterprise Security

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.

Search

 1`cisco_isovalent_process_exec`  process_name="curl"  
 2
 3| regex process="(?i)(?<!\w)-(?:[a-z]*k[a-z]*
 4|-(insecure
 5|proxy-insecure
 6|doh-insecure))"
 7
 8| stats count min(_time) as firstTime max(_time) as lastTime values(process) as process
 9    by cluster_name pod_name parent_process_name process_name process_exec process_id node_name
10
11| `security_content_ctime(firstTime)`
12
13| `security_content_ctime(lastTime)`
14
15| `cisco_isovalent___curl_execution_with_insecure_flags_filter`

Data Source

Name	Platform	Sourcetype	Source
Cisco Isovalent Process Exec	Other	`'cisco:isovalent:processExec'`	`'not_applicable'`

Macros Used

Name	Value
cisco_isovalent_process_exec	`sourcetype=cisco:isovalent:processExec`
cisco_isovalent___curl_execution_with_insecure_flags_filter	`search *`

cisco_isovalent___curl_execution_with_insecure_flags_filter is an empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.

Annotations

- MITRE ATT&CK

+ Kill Chain Phases

+ NIST

+ CIS

- Threat Actors

ID	Technique	Tactic
T1105	Ingress Tool Transfer	Command And Control

Command and Control

DE.AE

CIS 10

Default Configuration

This detection is configured by default in Splunk Enterprise Security to run with the following settings:

Setting	Value
Disabled	true
Cron Schedule	`0 * * * *`
Earliest Time	`-70m@m`
Latest Time	`-10m@m`
Schedule Window	`auto`
Creates Risk Event	True

This configuration file applies to all detections of type anomaly. These detections will use Risk Based Alerting.

Implementation

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.

Associated Analytic Story

Cisco Isovalent Suspicious Activity

Risk Based Analytics (RBA)

Risk Message:

A curl execution with insecure flags has been detected on pod_name [$pod_name$] in the cluster [$cluster_name$]

Risk Object	Risk Object Type	Risk Score	Threat Objects
pod_name	system	45	process_name

References

Detection Testing

Test Type	Status	Dataset	Source	Sourcetype
Validation	✅ Passing	N/A	N/A	N/A
Unit	✅ Passing	Dataset	`not_applicable`	`cisco:isovalent:processExec`
Integration	✅ Passing	Dataset	`not_applicable`	`cisco:isovalent:processExec`

Replay any dataset to Splunk Enterprise by using our replay.py tool or the UI. Alternatively you can replay a dataset into a Splunk Attack Range

Source: GitHub | Version: 1