Cisco IOS XE Log Clearing Sequence With Optional Loopback Removal

SPLUNK detection rule by Nasreddine Bencherchali · Apache-2.0

This analytic detects Cisco IOS-XE command sequences where show logging, clear logging, and exit occur within a short period. It also detects the pattern where a loopback interface is removed before clearing logs and exiting.

name: Cisco IOS XE Log Clearing Sequence With Optional Loopback Removal
id: e20a6709-5f2c-4508-83fb-b3af6f705717
version: 1
creation_date: '2026-05-19'
modification_date: '2026-05-20'
author: Nasreddine Bencherchali
status: production
type: Anomaly
description: |
    This analytic detects Cisco IOS-XE command sequences where show logging, clear logging, and exit occur within a short period.
    It also detects the pattern where a loopback interface is removed before clearing logs and exiting.
data_source:
    - Cisco IOS Logs
search: |-
    `cisco_ios`
    facility IN ("AAA", "HA_EM", "PARSER")
    mnemonic IN ("AAA_ACCOUNTING_MESSAGE", "LOG", "CFGLOG_LOGGEDCMD")
    message_text IN ("*show logging*", "*clear logging*", "*exit*", "*no interface Loopback*")

    | eval cmd=lower(coalesce(command, message_text))
    | eval event_type=case(
                like(cmd, "%show logging%"), "show_logging",
                like(cmd, "%clear logging%"), "clear_logging",
                like(cmd, "%exit%"), "exit",
                like(cmd, "%no interface loopback%"), "remove_loopback"
            )
    | where isnotnull(event_type)
    | eval dest=coalesce(host, dvc, dest, "unknown")
    | bin _time span=2m
    | stats count min(_time) as firstTime
                  max(_time) as lastTime
                  values(event_type) as event_types
                  values(message_text) as message_text
                  values(cmd) as cmd
      by _time dest
    | where mvfind(event_types, "clear_logging") >= 0
            AND
            mvfind(event_types, "exit") >= 0
            AND
            (
                mvfind(event_types, "show_logging") >= 0
                OR
                mvfind(event_types, "remove_loopback") >= 0
            )
    | `security_content_ctime(firstTime)`
    | `security_content_ctime(lastTime)`
    | `cisco_ios_xe_log_clearing_sequence_with_optional_loopback_removal_filter`
how_to_implement: |
    Use the Cisco Catalyst Add-on for Splunk (https://splunkbase.splunk.com/app/7538) to Ingest Cisco IOS-XE syslog with sourcetype "cisco:ios".
    Command visibility requires AAA command accounting, archive/config logging for configuration commands, or EEM catchall logging.
known_false_positives: |
    No false positives have been identified at this time.
references:
    - https://www.cisa.gov/news-events/cybersecurity-advisories/aa25-239a
    - https://blog.talosintelligence.com/salt-typhoon-analysis/
drilldown_searches:
    - name: View the detection results for - "$dest$"
      search: '%original_detection_search% | search  dest = "$dest$"'
      earliest_offset: $info_min_time$
      latest_offset: $info_max_time$
    - name: View risk events for the last 7 days for - "$dest$"
      search: '| from datamodel Risk.All_Risk | search normalized_risk_object IN ("$dest$") | 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: dest
          type: system
          score: 20
          message: Cisco IOS-XE log clearing sequence was observed on $dest$.
threat_objects: []
analytic_story:
    - Salt Typhoon
asset_type: Network
mitre_attack_id:
    - T1070.001
    - T1562
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/emerging_threats/SaltTyphoon/salttyphoon_cisco.log
          source: ctb:catalyst:syslog
          sourcetype: cisco:ios
      test_type: unit

[[ currentRule.title && currentRule.title.length > 60 ? currentRule.title.slice(0, 60) + '…' : currentRule.title ]]

c1512b3b-dc06-4e7b-bb52-779aff41baab

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Executable code, not a declarative rule

This submission is arbitrary [[ currentRule.format ? currentRule.format.toUpperCase() : '' ]] code, not a declarative detection rule — review it as you would any script before running it, and note that it cannot be safely aggregated or auto-executed alongside YARA/Sigma/Suricata/CRS rules.

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Format & documentation suggestions

Not a security issue — this rule is valid and was accepted as-is. These are optional fields/conventions its own format recommends, mainly affecting its quality score and how well it documents itself for other reviewers.

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