Detection: Splunk risky Command Abuse disclosed february 2023

Updated Date: 2024-07-23 ID: ee69374a-d27e-4136-adac-956a96ff60fd Author: Chase Franklin, Rod Soto, Eric McGinnis, Splunk Type: Hunting Product: Splunk Enterprise Security

Description

The following analytic identifies the execution of high-risk commands associated with various Splunk vulnerability disclosures. It leverages the Splunk_Audit.Search_Activity datamodel to detect ad-hoc searches by non-system users that match known risky commands. This activity is significant for a SOC as it may indicate attempts to exploit known vulnerabilities within Splunk, potentially leading to unauthorized access or data exfiltration. If confirmed malicious, this could allow attackers to execute arbitrary code, escalate privileges, or persist within the environment, posing a severe threat to the organization's security posture.

1
2| tstats fillnull_value="N/A" count min(_time) as firstTime max(_time) as lastTime from datamodel=Splunk_Audit.Search_Activity where Search_Activity.search_type=adhoc Search_Activity.user!=splunk-system-user by Search_Activity.search Search_Activity.info Search_Activity.total_run_time Search_Activity.user Search_Activity.search_type 
3| `drop_dm_object_name(Search_Activity)` 
4| lookup splunk_risky_command splunk_risky_command as search output splunk_risky_command description vulnerable_versions CVE 
5| where splunk_risky_command != "false" 
6| `security_content_ctime(firstTime)` 
7| `security_content_ctime(lastTime)` 
8| `splunk_risky_command_abuse_disclosed_february_2023_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_risky_command_abuse_disclosed_february_2023_filter search *
splunk_risky_command_abuse_disclosed_february_2023_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
T1202 Indirect Command Execution Privilege Escalation
KillChainPhase.EXPLOITAITON
NistCategory.DE_AE
Cis18Value.CIS_10
Lazarus Group

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 implementation of Splunk_Audit.Search_Activity datamodel.

Known False Positives

This search encompasses many commands.

Associated Analytic Story

Risk Based Analytics (RBA)

Risk Message Risk Score Impact Confidence
Use of risky splunk command $splunk_risky_command$ detected by $user$ 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 audittrail audittrail
Integration ✅ Passing Dataset audittrail audittrail

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: 5