Detection: Ollama Abnormal Service Crash Availability Attack

EXPERIMENTAL DETECTION

This detection status is set to experimental. The Splunk Threat Research team has not yet fully tested, simulated, or built comprehensive datasets for this detection. As such, this analytic is not officially supported. If you have any questions or concerns, please reach out to us at research@splunk.com.

Updated Date: 2025-10-05 ID: 327fa152-9b56-4e4e-bc0b-2795d4068afa Author: Rod Soto Type: Anomaly Product: Splunk Enterprise Security

Description

Detects critical service crashes, fatal errors, and abnormal process terminations in Ollama that may indicate exploitation attempts, resource exhaustion attacks, malicious input triggering unhandled exceptions, or deliberate denial of service attacks designed to disrupt AI model availability and degrade system stability.

Search

 1`ollama_server` (level=ERROR OR level=FATAL OR "service stopped" OR "terminated" OR "exit" OR "shutdown" OR "crash" OR "killed") 
 2| rex field=_raw "msg=\"(?<msg>[^\"]+)\"" 
 3| rex field=_raw "exit_code=(?<exit_code>\d+)" 
 4| bin _time span=5m 
 5| stats count as termination_count, earliest(_time) as first_seen, latest(_time) as last_seen, values(msg) as error_messages, values(exit_code) as exit_codes, dc(msg) as unique_errors by host 
 6| eval first_seen=strftime(first_seen, "%Y-%m-%d %H:%M:%S") 
 7| eval last_seen=strftime(last_seen, "%Y-%m-%d %H:%M:%S") 
 8| eval severity=case( termination_count > 5, "critical", termination_count > 2, "high", 1=1, "medium" ) 
 9| eval attack_type=case( termination_count > 5, "Resource Exhaustion", termination_count > 2, "Repeated Service Failures", 1=1, "Service Instability" ) 
10| where termination_count > 1 
11| table first_seen, last_seen, host, termination_count, unique_errors, error_messages, severity, attack_type 
12| `ollama_abnormal_service_crash_availability_attack_filter`

Data Source

Name	Platform	Sourcetype	Source
Ollama Server	N/A	`'ollama:server'`	`'server.log'`

Macros Used

Name	Value
ollama_server	`(sourcetype="ollama:server")`
ollama_abnormal_service_crash_availability_attack_filter	`search *`

ollama_abnormal_service_crash_availability_attack_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
T1489	Service Stop	Impact

Actions on Objectives

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

Ingest Ollama logs via Splunk TA-ollama add-on by configuring file monitoring inputs pointed to your Ollama server log directories (sourcetype: ollama:server), or enable HTTP Event Collector (HEC) for real-time API telemetry and prompt analytics (sourcetypes: ollama:api, ollama:prompts). CIM compatibility using the Web datamodel for standardized security detections.

Known False Positives

Normal service restarts during system updates or maintenance windows, graceful shutdowns with non-zero exit codes, intentional service stops by administrators, software upgrades requiring process termination, out-of-memory conditions on resource-constrained systems, or known bugs in specific Ollama versions that cause benign crashes may trigger this detection during routine operations.

Associated Analytic Story

Suspicious Ollama Activities

Risk Based Analytics (RBA)

Risk Message:

Abnormal Ollama service termination detected on host $host$ between $first_seen$ and $last_seen$. Service stopped $termination_count$ times with $unique_errors$ unique error types. Severity: $severity$. Potential cause: $attack_type$. Error messages: $error_messages$ require investigation.

Risk Object	Risk Object Type	Risk Score	Threat Objects
host	system	10	No Threat Objects

References

https://github.com/rosplk/ta-ollama

Detection Testing

Test Type	Status	Dataset	Source	Sourcetype
Validation	Not Applicable	N/A	N/A	N/A
Unit	✅ Passing	Dataset	`app.log`	`ollama:server`
Integration	✅ Passing	Dataset	`app.log`	`ollama:server`

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