On May 3rd, 2022, Splunk published a security advisory for username enumeration stemming from verbose login failure messages present on some REST endpoints. This detection will alert on attempted exploitation in patched versions of Splunk as well as actual exploitation in unpatched version of Splunk.
- Type: TTP
Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud
- Last Updated: 2022-04-29
- Author: Lou Stella, Splunk
- ID: 25625cb4-1c4d-4463-b0f9-7cb462699cde
|T1078||Valid Accounts||Defense Evasion, Initial Access, Persistence, Privilege Escalation|
Kill Chain Phase
- CIS 3
- CIS 5
- CIS 16
1 2 3 4 5 `splunkd_failed_auths` | stats count(user) as auths by user, src | where auths>5 | stats values(user) as "Users", sum(auths) as TotalFailedAuths by src | `splunk_user_enumeration_attempt_filter`
The SPL above uses the following Macros:
Note that splunk_user_enumeration_attempt_filter is a empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.
How To Implement
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Automation executing authentication attempts against your Splunk infrastructure with outdated credentials may cause false positives.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
|40.0||50||80||$TotalFailedAuths$ failed authentication events to Splunk from $src$ detected.|
source | version: 1