Cisco ASA - New Local User Account Created
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…
Description
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.
Detection logic
Detection requirements
- Platform
- ContainersESXiLinuxmacOSNetwork DevicesWindows
The rule states no platform. This is derived from the 2 ATT&CK techniques it maps to.
- Log source category
- cisco_asa_logs
Known benign triggers
- 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.
MITRE ATT&CK mappings
0 exclusive techniques.This is coverage no other published rule has; it is not this rule's total technique count.
References
| Reference | Cited by |
|---|---|
| www.cisco.com/c/en/us/td/docs/security/asa/syslog/asa-syslog/syslog-messages-500000-to-520025.html#con_4773963 | 3 |
From the source
- At source
- Open at source
- Upstream identifier
- 9c8e4f2a-7d3b-4e5c-8a9f-1b6d4e8c3f5a
- Tagged by the source as
- Suspicious Cisco Adaptive Security Appliance ActivityNetworkapplicationSplunk CloudSplunk EnterpriseSplunk Enterprise Securitynetwork
Licence
- Published under
- Apache License 2.0Read the licence
- Attribution
- Required
- Obtained under
- Apache-2.0Read the origin licence
Authorship
- Written by
- Published
- Aug 26, 2026
- Version
- 1