Cisco ASA - AAA Policy Tampering

name: Cisco ASA - AAA Policy Tampering
id: 8f2c4e9a-5d3b-4c7e-9a1f-6e8d5b2c3a9f
version: 5
creation_date: '2025-11-21'
modification_date: '2026-05-13'
author: Nasreddine Bencherchali, Splunk
status: production
type: Anomaly
description: |
    This analytic detects modifications to authentication and authorization (AAA) security policies on Cisco ASA devices via CLI or ASDM.
    AAA policies control critical security mechanisms including authentication attempts, lockout thresholds, password policies, and access control settings that protect administrative access to network infrastructure.
    Adversaries or malicious insiders may weaken authentication policies to facilitate brute force attacks, disable account lockouts to enable unlimited password attempts, reduce password complexity requirements, or modify authorization settings to elevate privileges and maintain persistent access.
    The detection monitors for command execution events containing AAA-related commands such as `aaa authentication`, `aaa authorization`, or `aaa local authentication`, focusing on changes to authentication attempts, lockout policies, and access control configurations.
    Investigate any unauthorized modifications to AAA policies, especially changes that weaken security posture (increasing max-fail attempts, disabling lockouts, reducing password requirements), and verify these changes against approved change management processes and security policies.
data_source:
    - Cisco ASA Logs
search: |
    `cisco_asa`
    message_id IN (111008, 111010)
    command IN (
        "aaa authentication*",
        "aaa authorization*",
        "aaa local authentication*",
        "aaa-server*",
        "no aaa*"
    )
    | fillnull
    | stats count
            earliest(_time) as firstTime
            latest(_time) as lastTime
            values(user) as user
            values(action) as action
            values(message_id) as message_id
            values(command) as command
            values(src_ip) as src_ip
            values(process_name) as process_name
      by host
    | `security_content_ctime(firstTime)`
    | `security_content_ctime(lastTime)`
    | `cisco_asa___aaa_policy_tampering_filter`
how_to_implement: |
    This search requires Cisco ASA syslog data to be ingested into Splunk via the Cisco Security Cloud TA.
    To ensure this detection works effectively, configure your ASA and FTD devices to generate and forward message ID 111008 and 111010.
    If your logging level is set to 'Notifications' or higher, these messages should already be included, else we recommend setting an event list that keeps the severity level you are using and adds message IDs 111008 and 111010.
    You can find specific instructions on how to set this up here : https://www.cisco.com/c/en/us/support/docs/security/pix-500-series-security-appliances/63884-config-asa-00.html.
    You can also change the severity level of the above message id's to the syslog level you have currently enabled using the logging message syslog_id level severity_level command in global configuration mode. For more information, see Change the Severity Level of a Syslog Message : https://www.cisco.com/c/en/us/td/docs/security/asa/asa922/configuration/general/asa-922-general-config/monitor-syslog.html#ID-2121-000006da
known_false_positives: |
    Legitimate AAA configuration modifications may occur during normal administrative activities such as implementing new security policies, adjusting lockout thresholds or troubleshooting authentication issues. These events should be verified and investigated. Consider filtering modifications performed by known administrative accounts where necessary.
references:
    - https://www.cisco.com/c/en/us/td/docs/security/asa/asa-cli-reference/A-H/asa-command-ref-A-H/aa-ac-commands.html
drilldown_searches:
    - name: View the detection results for $host$
      search: '%original_detection_search% | search  host = $host$'
      earliest_offset: $info_min_time$
      latest_offset: $info_max_time$
    - name: View risk events for the last 7 days for $host$
      search: '| from datamodel Risk.All_Risk | search normalized_risk_object IN ($host$) | stats count min(_time) as firstTime max(_time) as lastTime values(search_name) as "Search Name" values(risk_message) as "Risk Message" values(analyticstories) as "Analytic Stories" values(annotations._all) as "Annotations" values(annotations.mitre_attack.mitre_tactic) as "ATT&CK Tactics" by normalized_risk_object | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)`'
      earliest_offset: 7d
      latest_offset: "0"
intermediate_findings:
    entities:
        - field: host
          type: system
          score: 20
          message: User $user$ executed command $command$ to modify AAA configuration on Cisco ASA host $host$.
threat_objects:
    - field: command
      type: process
analytic_story:
    - Suspicious Cisco Adaptive Security Appliance Activity
asset_type: Network
mitre_attack_id:
    - T1556.004
product:
    - Splunk Enterprise
    - Splunk Enterprise Security
    - Splunk Cloud
category: application
security_domain: network
tests:
    - name: True Positive Test
      attack_data:
        - data: https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/cisco_asa/generic/cisco_asa_generic_logs.log
          source: not_applicable
          sourcetype: cisco:asa
      test_type: unit