Splunk

Cisco ASA - New Local User Account Created

Last updated 2 days ago on 2026-07-17

About

This analytic detects creation of new user accounts on Cisco ASA devices via CLI or ASDM. Adversaries may create unauthorized user accounts to establish persistence, maintain backdoor access, or elevate privileges on network infrastructure devices. These rogue accounts can provide attackers with continued access even after initial compromise vectors are remediated. The detection monitors for ASA message ID 502101, which is generated whenever a new user account is created on the device, capturing details including the username, privilege level, and the administrator who created the account. Investigate unexpected account creations, especially those with elevated privileges (level 15), accounts created outside business hours, accounts with suspicious or generic names, or accounts created by non-administrative users.
Platform
Splunk
Tags
Data Source: SplunkDomain: ApplicationRule Type: QueryOS: Any
Severity
medium
Risk Score
47
References
https://www.cisco.com/c/en/us/td/docs/security/asa/syslog/asa-syslog/syslog-messages-500000-to-520025.html#con_4773963(external, opens in a new tab or window)
False Positives
Legitimate account creation occurs during employee onboarding, contractor provisioning, service account setup, or emergency access. Verify against HR records and change management tickets. Filter known admin accounts during business hours.
Source
View on GitHub(external, opens in a new tab or window)

Definition

Rule Language
SPL
Rule Type
query
text code block:
`cisco_asa` message_id IN (502101) | fillnull | stats count earliest(_time) as firstTime latest(_time) as lastTime values(action) as action values(message_id) as message_id values(result) as result values(privilege_level) as privilege_level by host user | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)` | `cisco_asa___new_local_user_account_created_filter`

View this rule on Splunk

This rule was sourced from the official Splunk public repository. View the original rule on GitHub(external, opens in a new tab or window).