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Security Onion vs Splunk Enterprise Security comparison

 

Comparison Buyer's Guide

Executive SummaryUpdated on Apr 6, 2025

Review summaries and opinions

We asked business professionals to review the solutions they use. Here are some excerpts of what they said:
 

Categories and Ranking

Security Onion
Ranking in Log Management
18th
Average Rating
7.6
Reviews Sentiment
5.5
Number of Reviews
3
Ranking in other categories
AWS Marketplace (5th)
Splunk Enterprise Security
Ranking in Log Management
2nd
Average Rating
8.4
Reviews Sentiment
7.6
Number of Reviews
306
Ranking in other categories
Security Information and Event Management (SIEM) (1st), IT Operations Analytics (1st)
 

Mindshare comparison

As of May 2025, in the Log Management category, the mindshare of Security Onion is 5.5%, up from 3.4% compared to the previous year. The mindshare of Splunk Enterprise Security is 7.3%, down from 10.7% compared to the previous year. It is calculated based on PeerSpot user engagement data.
Log Management
 

Featured Reviews

Jörg Kippe - PeerSpot reviewer
A mature and affordable solution that is easy to install and easy to update
The product takes time to learn, it's not that easy. In the beginning we had a lot of questions. If you want to use such a tool in an real (industrial) environment, you have to ask how to get the network data. Can we do a full packet capture? Can we provide agents to our end systems? There are no simple solutions to these questions. It's a general problem when running such systems in an industrial environment.
ROBERT-CHRISTIAN - PeerSpot reviewer
Has many predefined correlation rules and is brilliant for investigation and log analysis
It is very complicated to write your own correlation rules without the help of Splunk support. What Splunk could do better is to create an API to the standard SIEM tools, such as Microsoft Sentinel. The idea would be to make it less painful. In ELK Stack, Kibana is the query language with which you can search log files. I believe Splunk has also a query language in which they search their log files, but once you have identified the log file that you want to use for further security correlation, you want to very quickly transport that into your SIEM tool, such as Microsoft Sentinel. That is something that Splunk could make a little bit less painful because it is a lot of effort to find that log file and forward it. An API with Microsoft Sentinel or a similar SIEM tool would be a good idea.

Quotes from Members

We asked business professionals to review the solutions they use. Here are some excerpts of what they said:
 

Pros

"The most valuable feature of Security Onion for security monitoring is its ability to find infected ports."
"We use Security Onion for internal vulnerability assessment."
"Security Onion is the most mature solution in the market."
"I like Splunk's data aggregation and search capabilities."
"Splunk Enterprise Security is able to process a huge amount of data without any issues."
"Its alerting is most valuable. We have alerts set up in our environment for certain attacks, such as an SQL injection attempt. We have a front-facing server for the website. It is out there, and anybody can access it. When those SQL injection attempts come in, we are able to detect that with the alert."
"With good domain knowledge, one can build almost anything. If you throw in Alert Manager or an integration with ServiceNow. Then, you have your own SIEM"
"Splunk Enterprise Security enhances business resilience and assists with threat detection by centralizing security data."
"Splunk has significantly reduced the time in performing the task of aggregating logs, reviewing as well as time spent during investigations."
"The most valuable features include agility and Splunk Enterprise Security's ability to quickly search for alerted items, as well as the capacity to create custom alerts using the SQL language employed by Splunk."
"The benefits my company has seen from the use of Splunk Enterprise Security revolve around the speed of detection it offers."
 

Cons

"The product is not easy to learn."
"Security Onion's user interface could be improved."
"The initial setup of the solution is a little bit difficult."
"Being a SIEM solution with a centralized dashboard, we would like to have more options to customize it."
"We usually have to follow up with technical support on our open cases."
"An improved user interface along with multi-tenancy support would be beneficial."
"Splunk Enterprise Security can provide more details and help CISOs resolve vulnerability situations better. The reason is that the tools we choose for data analysis and log collection cannot collect all the data and logs. Splunk Enterprise Security should help me with this, but it cannot."
"In the next releases, I would like to see more pricing flexibility."
"The threat detection system has room for improvement."
"I'd say I am happy with the technical support, not elated. They provide great support, but sometimes they don't have the answers that I need."
"Most importantly, Splunk can be outrageously expensive. That is the problem with both Splunk and Sentinel. Their pricing literally explodes based on the amount of data you feed in."
 

Pricing and Cost Advice

"It is an open-source solution."
"Security Onion is an open-source solution."
"Security Onion is a free solution."
"ROI is estimated at saving my team roughly 10 to 12 man hours per week in troubleshooting for our company as well as what our profits had been from our services of installing, configuring, and supporting other clients with the product."
"It can be tough to determine if you are getting all of the value out of your investment at times."
"It is quite expensive."
"Although Splunk is an expensive product, it is designed to be utilized across your organization in order to maximize your ROI and lower your TCO."
"Free Splunk license for PoCs on personal machines and the ability to scale the PoC to an enterprise level app."
"It is not cheap."
"The pricing seems good relative to the other vendors that we have had here. However, they need to find ways to be more flexible with the licensing and be able to deal with situations where we start generating more logs. Maybe having some controls in the Splunk interface to turn it off, so we don't have to change anything in our application."
"It's more expensive than the other tools, but it's worth it. Every penny is worth it."
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Comparison Review

VS
Feb 26, 2015
HP ArcSight vs. IBM QRadar vs. ​McAfee Nitro vs. Splunk vs. RSA Security vs. LogRhythm
We at Infosecnirvana.com have done several posts on SIEM. After the Dummies Guide on SIEM, we are following it up with a SIEM Product Comparison – 101 deck. So, here it is for your viewing pleasure. Let me know what you think by posting your comments below. The key products compared here are…
 

Top Industries

By visitors reading reviews
University
12%
Computer Software Company
12%
Government
11%
Comms Service Provider
11%
Financial Services Firm
15%
Computer Software Company
14%
Manufacturing Company
8%
Government
8%
 

Company Size

By reviewers
Large Enterprise
Midsize Enterprise
Small Business
No data available
 

Questions from the Community

What do you like most about Security Onion?
The most valuable feature of Security Onion for security monitoring is its ability to find infected ports.
What is your experience regarding pricing and costs for Security Onion?
Security Onion is an open-source solution. On a scale from one to ten, where ten is expensive and one is cheap, I rate the solution's pricing a six out of ten.
What needs improvement with Security Onion?
The initial setup of the solution is a little bit difficult.
What SOC product do you recommend?
For tools I’d recommend: -SIEM- LogRhythm -SOAR- Palo Alto XSOAR Doing commercial w/o both (or at least an XDR) is asking to miss details that are critical, and ending up a statistic. Also, rememb...
What is a better choice, Splunk or Azure Sentinel?
It would really depend on (1) which logs you need to ingest and (2) what are your use cases Splunk is easy for ingestion of anything, but the charge per GB/Day Indexed and it gets expensive as log ...
How does Splunk compare with Azure Monitor?
Splunk handles a high amount of data very well. We use Splunk to capture information and as an aggregator for monitoring information from different sources. Splunk is very good at alerting us if we...
 

Overview

 

Sample Customers

Information Not Available
Splunk has more than 7,000 customers spread across over 90 countries. These customers include Telenor, UniCredit, ideeli, McKenney's, Tesco, and SurveyMonkey.
Find out what your peers are saying about Security Onion vs. Splunk Enterprise Security and other solutions. Updated: April 2025.
849,686 professionals have used our research since 2012.