{"description":"Trending threats, MITRE ATT\u0026CK coverage, and detection metadata. Fed continuously.","feed_url":"https://feed.craftedsignal.io/tags/user-enumeration/feed.json","home_page_url":"https://feed.craftedsignal.io/","items":[{"_cs_actors":[],"_cs_cpes":["cpe:2.3:a:splunk:splunk:*:*:*:*:enterprise:*:*:*"],"_cs_cves":[{"cvss":5.3,"id":"CVE-2021-33845"}],"_cs_exploited":false,"_cs_has_poc":false,"_cs_poc_references":[],"_cs_products":["Splunk Enterprise","Splunk Enterprise Security","Splunk Cloud"],"_cs_severities":["medium"],"_cs_tags":["user-enumeration","splunk","authentication","application"],"_cs_type":"advisory","_cs_vendors":["Splunk"],"content_html":"\u003cp\u003eThis brief describes detection logic aimed at identifying attempts to enumerate valid usernames within Splunk Enterprise or Splunk Cloud environments. Threat actors initiate numerous failed authentication attempts from a single source IP address against a Splunk instance's login interface. By observing the responses (e.g., specific error messages or timing differences), attackers can discern which usernames are valid, even if the password is incorrect. This activity is a critical precursor to more advanced attacks such as password spraying or brute-force credential attacks, as outlined in the linked Splunk security content. While the detection specifically targets user enumeration, it can also help identify broader credential-based attack campaigns. The behavior is observable within Splunk's internal \u003ccode\u003e_audit\u003c/code\u003e index, which records authentication events. A related security advisory for Splunk's login page, CVE-2021-33845, pertains to a Cross-site Scripting vulnerability, though this brief's detection focuses on enumeration behavior rather than direct exploitation of that specific CVE.\u003c/p\u003e\n\u003ch2 id=\"attack-chain\"\u003eAttack Chain\u003c/h2\u003e\n\u003col\u003e\n\u003cli\u003e\u003cstrong\u003eReconnaissance \u0026amp; Target Identification\u003c/strong\u003e: Attacker identifies a publicly accessible Splunk instance via open-source intelligence or scanning.\u003c/li\u003e\n\u003cli\u003e\u003cstrong\u003eInitial Enumeration Attempt\u003c/strong\u003e: Attacker initiates multiple authentication attempts using common or guessed usernames (e.g., \u003ccode\u003eadmin\u003c/code\u003e, \u003ccode\u003esplunkadmin\u003c/code\u003e, \u003ccode\u003euser1\u003c/code\u003e) combined with incorrect passwords.\u003c/li\u003e\n\u003cli\u003e\u003cstrong\u003eFailed Authentication Logging\u003c/strong\u003e: The Splunk instance processes these login attempts and logs failures (action=login, status=failure) in its internal \u003ccode\u003e_audit\u003c/code\u003e index.\u003c/li\u003e\n\u003cli\u003e\u003cstrong\u003eResponse Analysis\u003c/strong\u003e: Attacker analyzes the HTTP responses or error messages from the Splunk login interface, or relies on the sheer volume of failed attempts, to distinguish between invalid usernames and valid usernames with incorrect passwords.\u003c/li\u003e\n\u003cli\u003e\u003cstrong\u003eUsername List Generation\u003c/strong\u003e: A list of confirmed valid Splunk usernames is compiled based on the enumeration results.\u003c/li\u003e\n\u003cli\u003e\u003cstrong\u003eCredential-Based Attack Preparation\u003c/strong\u003e: The attacker uses the gathered valid usernames for subsequent credential-based attacks such as password spraying or brute-forcing.\u003c/li\u003e\n\u003cli\u003e\u003cstrong\u003eInitial Access Attempt\u003c/strong\u003e: Attacker attempts to log into the Splunk instance using the valid usernames and compromised or guessed passwords.\u003c/li\u003e\n\u003cli\u003e\u003cstrong\u003eUnauthorized Access \u0026amp; Impact\u003c/strong\u003e: Successful login grants unauthorized access to the Splunk environment, potentially leading to sensitive data exfiltration, dashboard manipulation, or further compromise of integrated systems.\u003c/li\u003e\n\u003c/ol\u003e\n\u003ch2 id=\"impact\"\u003eImpact\u003c/h2\u003e\n\u003cp\u003eSuccessful user enumeration provides threat actors with a critical piece of information—valid usernames—that significantly streamlines subsequent credential-based attacks. If these attacks succeed, they can lead to unauthorized access to the Splunk environment. This unauthorized access can result in the exposure, modification, or deletion of sensitive enterprise data, compromise of security monitoring capabilities, and serve as a pivot point for lateral movement into other systems. The integrity and confidentiality of data managed or monitored by Splunk instances are at severe risk.\u003c/p\u003e\n\u003ch2 id=\"recommendation\"\u003eRecommendation\u003c/h2\u003e\n\u003cul\u003e\n\u003cli\u003eReview the \u003ccode\u003e_audit\u003c/code\u003e index for \u003ccode\u003eaction=login\u003c/code\u003e events with \u003ccode\u003estatus=failure\u003c/code\u003e that show a high count from a single \u003ccode\u003esrc\u003c/code\u003e IP address targeting different \u003ccode\u003euser\u003c/code\u003e accounts, indicating potential user enumeration attempts.\u003c/li\u003e\n\u003cli\u003eImplement strong account lockout policies within Splunk to deter brute-force and password spraying attacks that leverage enumerated usernames.\u003c/li\u003e\n\u003cli\u003eEnsure multi-factor authentication (MFA) is enforced for all Splunk user accounts, especially those with administrative privileges.\u003c/li\u003e\n\u003cli\u003eMonitor for high volumes of failed login attempts against your Splunk infrastructure and investigate their source and targeted accounts.\u003c/li\u003e\n\u003cli\u003eRegularly rotate credentials for Splunk accounts and enforce complex password requirements.\u003c/li\u003e\n\u003c/ul\u003e\n","date_modified":"2026-07-03T13:40:29Z","date_published":"2026-07-03T13:40:29Z","id":"https://feed.craftedsignal.io/briefs/2026-07-splunk-user-enumeration/","summary":"An attacker is attempting to enumerate valid Splunk usernames by repeatedly submitting failed authentication attempts from a single source, as detected by monitoring the `_audit` index for multiple login failures, which is a precursor to credential-based attacks like password spraying or brute force, potentially leading to unauthorized access and sensitive data exposure.","title":"Splunk User Enumeration Attempt Detection","url":"https://feed.craftedsignal.io/briefs/2026-07-splunk-user-enumeration/"}],"language":"en","title":"CraftedSignal Threat Feed - User-Enumeration","version":"https://jsonfeed.org/version/1.1"}