Detection: Splunk Enterprise KV Store Incorrect Authorization

Updated Date: 2024-05-10 ID: 8f0e8380-a835-4f2b-b749-9ce119364df0 Author: Rod Soto, Eric McGinnis, Chase Franklin Type: Hunting Product: Splunk Enterprise Security

Description

The following analytic detects unauthorized attempts to reload Splunk KV Store collections via the REST API. It leverages internal index logs to identify POST requests to the /servicesNS/nobody/search/admin/collections-conf/_reload endpoint, focusing on status codes starting with '2'. This activity is significant as it may indicate improper permission handling, potentially leading to unauthorized deletion of KV Store collections. If confirmed malicious, this could result in data loss or unauthorized data manipulation, impacting the integrity and availability of critical Splunk data.

1`splunkda` uri=/servicesNS/nobody/search/admin/collections-conf/_reload status=2* method="POST" user=* file=_reload 
2| stats count min(_time) as firstTime max(_time) as lastTime values(status) as status by host clientip file method 
3| `security_content_ctime(firstTime)` 
4| `security_content_ctime(lastTime)` 
5| `splunk_enterprise_kv_store_incorrect_authorization_filter`

Data Source

Name Platform Sourcetype Source Supported App
Splunk Splunk icon Splunk 'splunkd_ui_access' 'splunkd_ui_access.log' N/A

Macros Used

Name Value
security_content_ctime convert timeformat="%Y-%m-%dT%H:%M:%S" ctime($field$)
splunk_enterprise_kv_store_incorrect_authorization_filter search *
splunk_enterprise_kv_store_incorrect_authorization_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
T1548 Abuse Elevation Control Mechanism Defense Evasion
KillChainPhase.EXPLOITAITON
NistCategory.DE_AE
Cis18Value.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 False
This configuration file applies to all detections of type hunting.

Implementation

Requires access to internal indexes and REST API enabled instances.

Known False Positives

This is a hunting search and will produce false positives. Operator must follow results into instances where curl requests coming from actual users may indicate intent of exploitation.

Associated Analytic Story

Risk Based Analytics (RBA)

Risk Message Risk Score Impact Confidence
Possible attempt to access KV Store collections at $host$ 25 50 50
The Risk Score is calculated by the following formula: Risk Score = (Impact * Confidence/100). Initial Confidence and Impact is set by the analytic author.

References

Detection Testing

Test Type Status Dataset Source Sourcetype
Validation ✅ Passing N/A N/A N/A
Unit ✅ Passing Dataset /opt/splunk/var/log/splunk/splunkd_access.log splunkd_access
Integration ✅ Passing Dataset /opt/splunk/var/log/splunk/splunkd_access.log splunkd_access

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: 2