Detection rules › Splunk

Cisco Secure Firewall - Remote Access Software Usage Traffic

Status
production
Severity
low
Group by
ClientApplication, action, src
Author
Nasreddine Bencherchali, Splunk
Source
github.com/splunk/security_content

The following analytic detects network traffic associated with known remote access software applications that are covered by Cisco Secure Firewall Application Detectors, such as AnyDesk, GoToMyPC, LogMeIn, and TeamViewer. It leverages Cisco Secure Firewall Threat Defense Connection Event. This activity is significant because adversaries often use remote access tools to maintain unauthorized access to compromised environments. If confirmed malicious, this activity could allow attackers to control systems remotely, exfiltrate data, or deploy additional malware, posing a severe threat to the organization's security.

Known false positives

  • It is possible that legitimate remote access software is used within the environment. Known false positives can be added to the remote_access_software_usage_exception.csv lookup to globally suppress these situations across all remote access content

MITRE ATT&CK coverage

TacticTechniques
Command & Control

Rule body

name: Cisco Secure Firewall - Remote Access Software Usage Traffic
id: ac54d39e-a75d-4f42-971d-006db3a0423a
version: 9
creation_date: '2025-05-28'
modification_date: '2026-05-13'
author: Nasreddine Bencherchali, Splunk
status: production
type: Anomaly
description: |
    The following analytic detects network traffic associated with known remote access software applications
    that are covered by Cisco Secure Firewall Application Detectors, such as AnyDesk, GoToMyPC, LogMeIn, and TeamViewer.
    It leverages Cisco Secure Firewall Threat Defense Connection Event.
    This activity is significant because adversaries often use remote access tools to maintain unauthorized access to compromised environments.
    If confirmed malicious, this activity could allow attackers to control systems remotely, exfiltrate
    data, or deploy additional malware, posing a severe threat to the organization's security.
data_source:
    - Cisco Secure Firewall Threat Defense Connection Event
search: |
    `cisco_secure_firewall` EventType=ConnectionEvent
    | stats min(_time) as firstTime max(_time) as lastTime
          values(dest_port) as dest_port
          values(dest) as dest
          values(transport) as transport
          values(url) as url
          values(rule) as rule
          count by src ClientApplication action
    | `security_content_ctime(firstTime)`
    | `security_content_ctime(lastTime)`
    | lookup cisco_secure_firewall_appid_remote_mgmt_and_desktop_tools appName AS ClientApplication OUTPUT category, appDescription as Description
    | search category IN ("remote administration", "remote desktop control")
    | `remote_access_software_usage_exceptions`
    | `cisco_secure_firewall___remote_access_software_usage_traffic_filter`
how_to_implement: |
    This search requires Cisco Secure Firewall Threat Defense Logs, which
    includes the ConnectionEvent EventType. This search uses an input macro named `cisco_secure_firewall`.
    We strongly recommend that you specify your environment-specific configurations
    (index, source, sourcetype, etc.) for Cisco Secure Firewall Threat Defense logs. Replace the macro definition
    with configurations for your Splunk environment. The search also uses a post-filter
    macro designed to filter out known false positives.
    The logs are to be ingested using the Splunk Add-on for Cisco Security Cloud (https://splunkbase.splunk.com/app/7404).
    The access policy must also enable logging.
    The "exceptions" macro leverages both an Assets and Identities lookup, as well as a KVStore collection called "remote_software_exceptions"
    that lets you track and maintain device- based exceptions for this set of detections.
known_false_positives: |
    It is possible that legitimate remote access software is used within the environment. Known false positives can be added to the remote_access_software_usage_exception.csv lookup to globally suppress these situations across all remote access content
references:
    - https://attack.mitre.org/techniques/T1219/
    - https://thedfirreport.com/2022/08/08/bumblebee-roasts-its-way-to-domain-admin/
    - https://thedfirreport.com/2022/11/28/emotet-strikes-again-lnk-file-leads-to-domain-wide-ransomware/
intermediate_findings:
    entities:
        - field: src
          type: system
          score: 20
          message: Traffic to known remote access software [$ClientApplication$] was detected from $src$.
threat_objects:
    - field: ClientApplication
      type: signature
analytic_story:
    - Insider Threat
    - Command And Control
    - Ransomware
    - Remote Monitoring and Management Software
    - Cisco Secure Firewall Threat Defense Analytics
    - Scattered Spider
    - Interlock Ransomware
    - Scattered Lapsus$ Hunters
asset_type: Network
mitre_attack_id:
    - T1219
product:
    - Splunk Enterprise
    - Splunk Enterprise Security
    - Splunk Cloud
category: network
security_domain: network

Stages and Predicates

Stage 1: search

`cisco_secure_firewall` EventType=ConnectionEvent

Stage 2: stats

| stats min(_time) as firstTime max(_time) as lastTime
      values(dest_port) as dest_port
      values(dest) as dest
      values(transport) as transport
      values(url) as url
      values(rule) as rule
      count by src ClientApplication action

Stage 3: search

| `security_content_ctime(firstTime)`

Stage 4: search

| `security_content_ctime(lastTime)`

Stage 5: lookup

| lookup cisco_secure_firewall_appid_remote_mgmt_and_desktop_tools appName AS ClientApplication OUTPUT category, appDescription as Description
Lookup table
cisco_secure_firewall_appid_remote_mgmt_and_desktop_tools
Key field
appName as ClientApplication
Output columns
['category', 'category'], ['appDescription', 'Description']

Stage 6: search

| search category IN ("remote administration", "remote desktop control")

Stage 7: search

| `remote_access_software_usage_exceptions`

Stage 8: search

| `cisco_secure_firewall___remote_access_software_usage_traffic_filter`

Exclusions

The rule actively suppresses these predicates.

FieldKindExcluded valuesSearch
rmm_exceptioneqTRUEexcludes:rmm_exception field:"rmm_exception" value:"TRUE"
rmm_exception_endin"FALSE", "UNLIMITED"excludes:rmm_exception_end

Indicators

These rows show field, operator, and value matches.

FieldKindValuesSearch
EventTypeeq
  • ConnectionEvent
field:"EventType" kind:eq value:"ConnectionEvent"
categoryin
  • "remote administration"
  • "remote desktop control"
field:"category" kind:in
sourcetypeeq
  • cisco:sfw:estreamer
field:"sourcetype" kind:eq value:"cisco:sfw:estreamer"