Splunk’s Search Processing Language (SPL) is a powerful tool designed to search, analyze, and visualize machine-generated data. Within this language, the ability to handle multivalue fields is crucial for parsing logs, identifying patterns, and extracting actionable insights.
Multivalue fields in Splunk are fields on events that contain more than one result. These can be easily made leveraging the ‘values()’ stats command, but they can be found in field extractions as well.
In previous posts we’ve explored essential commands like makemv, makecontinuous, mvexpand, and mvcombine. These tools help create, transform, and unify multivalue fields.
Today, we turn our attention to two complementary commands: mvfind and mvindex. These allow us to search for values within multivalue fields and extract specific elements by their position. Together, they provide fine control over complex datasets.
Whether you’re filtering threat intelligence feeds or analyzing grouped user activity logs, mvfind and mvindex are indispensable tools.
Understanding the Commands
mvfind returns the index position of the first match of a specified value within a multivalue field. It uses regular expressions to determine the match. This is helpful when you need to identify if a specific value is in a multivalue field, and where exactly in the multivalue list it resides.
mvindex extracts a specific value from a multivalue field based on its position. You can also specify a range to extract multiple values. This makes it easy to isolate or report on certain indexed entries.
Together, these commands offer positional and conditional logic that is hard to replicate with basic SPL.
Why Use These Commands?
These commands improve precision and flexibility when handling multivalue fields. Here are three key benefits:
- Targeted Value Extraction: Easily pull one or more specific values from multivalue fields using index-based access.
- Pattern Detection: Detect whether specific patterns or values exist and where they appear within a list.
- Efficient Data Filtering: Use logic tied to value position to drive dashboards and alerts.
Basic Syntax
mvfind
mvfind(<multivalue_field>, <"regex pattern">)
- Returns a positive integer corresponding to the index of the first element matching the regex pattern. The index count starts at 0, increasing by one for each element in the list.
- Returns -1 if not found.
mvindex
mvindex(<multivalue_field>, <start_index>, <end_index>)
- start_index: Required. The index of the value you want to extract. Remember that 0 is the first element of the multivalue list. This can be negative to start counting from the back of the multivalue field (-1 is the last object in the list, -2 is second to last).
- end_index: Optional. If used, extracts values from start to end index.
Example Use Cases
These commands shine in real-world use cases. Below are examples with both simple logic and CIM-aligned scenarios.
Example #1: Detecting IPs in a Threat List
Use Case: Identify if any IPs from a multivalue threat list match a known malicious pattern.
| eval mvindex=mvfind(threat_ip_list, "^192\.168\.")
| where mvindex > -1
Explanation: Many security logs include lists of IP addresses flagged by various threat intelligence sources. The field threat_ip_list might include multiple IPs in a single event. This example uses mvfind to check if any of those values start with 192.168., indicating an internal range. If a match is found, the search filters for that event. An analyst might use this to find cases where internal IPs appear in threat feeds, signaling misconfiguration or malicious tunneling.
Example #2: Extracting Usernames from Login Attempts
Use Case: Display only the second failed login attempt from the user_attempts field.
| eval second_attempt=mvindex(user_attempts, 1)
Explanation: Some authentication logs store usernames in a multivalue field showing all recent login attempts for a single session or host. In this case, the second value (index 1) represents the second user who attempted to log in. Analysts might extract this to analyze behavior across attempts, correlate timing patterns, or flag brute-force activity.
Example #3: Combining CIM and Positional Logic
Use Case: Within CIM’s Authentication data model, identify if a user attempted access using multiple methods and show the last method used.
| tstats values(Authentication.action) as actions, values(Authentication.method) as methods \
from datamodel=Authentication by Authentication.user
| eval last_method=mvindex(methods, -1)
Explanation: CIM-aligned data often aggregates actions and methods into multivalue fields. This example uses tstats to summarize authentication behavior per user. By applying mvindex(methods, -1), the search captures the last authentication method used—such as password, SSO, or token. Security teams can monitor for changes in method usage, detect account takeovers, or enforce policy compliance.
Conclusion
mvfind and mvindex add depth to your SPL toolbox. When you’re working with multivalue fields, these commands offer essential control and insight.
They allow you to:
- Pinpoint values using regex with mvfind
- Extract single or multiple values with mvindex
- Combine positional logic with other SPL functions for advanced use cases
Understanding and applying these commands can greatly enhance the way you interact with multivalue data in Splunk. By mastering them, you improve both search accuracy and dashboard functionality.
To access more Splunk searches, check out Atlas Search Library, which is part of the Atlas Platform. Specifically, Atlas Search Library offers a curated list of optimized searches. These searches empower Splunk users without requiring SPL knowledge. Furthermore, you can create, customize, and maintain your own search library. By doing so, you ensure your users get the most from using Splunk.
