ID | Technique | Tactic |
---|---|---|
T1078 | Valid Accounts | Defense Evasion |
Detection: Splunk User Enumeration Attempt
Description
The following analytic identifies attempts to enumerate usernames in Splunk by detecting multiple failed authentication attempts from the same source. It leverages data from the _audit
index, specifically focusing on failed authentication events. This activity is significant for a SOC because it can indicate an attacker trying to discover valid usernames, which is a precursor to more targeted attacks like password spraying or brute force attempts. If confirmed malicious, this activity could lead to unauthorized access, compromising the security of the Splunk environment and potentially exposing sensitive data.
Search
1`splunkd_failed_auths`
2| stats count(user) as auths by user, src
3| where auths>5
4| stats values(user) as user, sum(auths) as TotalFailedAuths by src
5| `splunk_user_enumeration_attempt_filter`
Data Source
Name | Platform | Sourcetype | Source |
---|---|---|---|
Splunk | Splunk | 'splunkd_ui_access' |
'splunkd_ui_access.log' |
Macros Used
Name | Value |
---|---|
splunkd_failed_auths | index=_audit "action=login attempt" "info=failed" |
splunk_user_enumeration_attempt_filter | search * |
splunk_user_enumeration_attempt_filter
is an empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.
Annotations
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 Notable | Yes |
Rule Title | %name% |
Rule Description | %description% |
Notable Event Fields | user, dest |
Creates Risk Event | True |
Implementation
This detection does not require you to ingest any new data. The detection does require the ability to search the _audit index. This detection may assist in efforts to find password spraying or brute force authorization attempts in addition to someone enumerating usernames.
Known False Positives
Automation executing authentication attempts against your Splunk infrastructure with outdated credentials may cause false positives.
Associated Analytic Story
Risk Based Analytics (RBA)
Risk Message | Risk Score | Impact | Confidence |
---|---|---|---|
$TotalFailedAuths$ failed authentication events to Splunk from $src$ detected. | 40 | 50 | 80 |
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