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Security Onion vs Splunk Enterprise Security comparison

 

Comparison Buyer's Guide

Executive SummaryUpdated on Jul 13, 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
21st
Average Rating
7.6
Reviews Sentiment
5.5
Number of Reviews
3
Ranking in other categories
No ranking in other categories
Splunk Enterprise Security
Ranking in Log Management
2nd
Average Rating
8.4
Reviews Sentiment
7.5
Number of Reviews
322
Ranking in other categories
Security Information and Event Management (SIEM) (1st), IT Operations Analytics (1st)
 

Mindshare comparison

As of July 2025, in the Log Management category, the mindshare of Security Onion is 5.0%, up from 4.4% compared to the previous year. The mindshare of Splunk Enterprise Security is 7.3%, down from 10.1% 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

"We use Security Onion for internal vulnerability assessment."
"The most valuable feature of Security Onion for security monitoring is its ability to find infected ports."
"Security Onion is the most mature solution in the market."
"It has a big user base, so the community is useful."
"The solution has plenty of features that are good."
"Exporting is a good feature. It helps me out when I have to do reports. I do a lot of exporting and crunching of the numbers. Dashboards are okay for showing to the leadership, but for doing statistics and updating tickets, the export feature is very beneficial for me."
"The log aggregation is great."
"Splunk Enterprise Security's most valuable features are its stability and the robust Splunk Search Processing Language, allowing extensive customization and analysis capabilities."
"I like Splunk's data aggregation and search capabilities."
"The product is good, it satisfies our customers."
"If properly built, I'm very impressed with the stability of Splunk ES."
 

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."
"Resource usage can probably be described as an area with shortcomings in the product where improvements are required."
"Splunk Enterprise Security has not helped reduce our alert volume."
"Customizing our commands should be simpler. Creating custom commands in Splunk requires a long, complex process. For example, we have a command to add all the column data, but we don't have a command to get the average of the column data at the end. It would be useful to have a blank at the end to create our commands and leave the rest to others."
"Data retention can be better. If we want to look at the data for five months or six months, that is not available to us. We only have a history of 20 or 30 days. After that, the information gets lost. That is a drawback."
"The tool should include more real-world use case examples built out either through videos or in the community."
"Most of my interaction is with the user community, which is how Splunk wants it. When I need help, that community is very hit or miss."
"One area Splunk Enterprise Security fails to improve is the pricing aspect; while the initial pricing seems fine, the licensing cost can skyrocket over time, creating trauma for organizations."
"I find that the learning curve for Splunk is relatively lengthy."
 

Pricing and Cost Advice

"Security Onion is an open-source solution."
"It is an open-source solution."
"Security Onion is a free solution."
"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."
"Splunk Enterprise Security's pricing is based on data volume, which generally suits large enterprises."
"Its pricing model can be improved."
"It's a little bit expensive for a small to medium enterprise."
"Pricing can be a limiting factor. You have to continuously tune what you are bringing in and make sure what you bring in is of value."
"Splunk differs from other SIEM solutions by using a gigabyte-based pricing model, rather than the agent-based licenses common with its competitors."
"The pricing modules could be improved."
"The price is comparable."
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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
Computer Software Company
11%
University
11%
Comms Service Provider
10%
Government
10%
Financial Services Firm
14%
Computer Software Company
14%
Manufacturing Company
8%
Government
7%
 

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: July 2025.
863,901 professionals have used our research since 2012.