Detection rules › Splunk

Windows Suspect Process With Authentication Traffic

Status
production
Severity
low
Group by
All_Traffic.action, All_Traffic.app, All_Traffic.dest, All_Traffic.direction, All_Traffic.dvc, All_Traffic.protocol, All_Traffic.protocol_version, All_Traffic.src, All_Traffic.src_port, All_Traffic.transport, All_Traffic.user, All_Traffic.vendor_product, dest_ip, destination_port, src_ip
Author
Steven Dick
Source
github.com/splunk/security_content

The following analytic detects executables running from public or temporary locations that are communicating over Windows domain authentication ports/protocols such as LDAP (389), LDAPS (636), and Kerberos (88). It leverages network traffic data to identify processes originating from user-controlled directories. This activity is significant because legitimate applications rarely run from these locations and attempt domain authentication, making it a potential indicator of compromise. If confirmed malicious, attackers could leverage this to access domain resources, potentially leading to further exploitation and lateral movement within the network.

MITRE ATT&CK coverage

Event coverage

ProviderEventTitle
SysmonEvent ID 3Network connection

Rule body splunk

name: Windows Suspect Process With Authentication Traffic
id: 953322db-128a-4ce9-8e89-56e039e33d98
version: 11
creation_date: '2023-07-28'
modification_date: '2026-05-13'
author: Steven Dick
status: production
type: Anomaly
description: The following analytic detects executables running from public or temporary locations that are communicating over Windows domain authentication ports/protocols such as LDAP (389), LDAPS (636), and Kerberos (88). It leverages network traffic data to identify processes originating from user-controlled directories. This activity is significant because legitimate applications rarely run from these locations and attempt domain authentication, making it a potential indicator of compromise. If confirmed malicious, attackers could leverage this to access domain resources, potentially leading to further exploitation and lateral movement within the network.
data_source:
    - Sysmon EventID 3
search: '| tstats `security_content_summariesonly` count min(_time) as firstTime max(_time) as lastTime values(All_Traffic.process_id) as process_id  from datamodel=Network_Traffic.All_Traffic where All_Traffic.dest_port IN ("88","389","636")  AND All_Traffic.app IN ("*\\users\\*", "*\\programdata\\*", "*\\temp\\*", "*\\Windows\\Tasks\\*", "*\\appdata\\*", "*\\perflogs\\*") by All_Traffic.action All_Traffic.app All_Traffic.dest All_Traffic.dest_ip All_Traffic.dest_port All_Traffic.direction All_Traffic.dvc All_Traffic.protocol All_Traffic.protocol_version All_Traffic.src All_Traffic.src_ip All_Traffic.src_port All_Traffic.transport All_Traffic.user All_Traffic.vendor_product | `drop_dm_object_name(All_Traffic)`  | rex field=app ".*\\\(?<process_name>.*)$" | `security_content_ctime(firstTime)`  | `security_content_ctime(lastTime)` | `windows_suspect_process_with_authentication_traffic_filter`'
how_to_implement: To implement this analytic, Sysmon should be installed in the environment and generating network events for  userland and/or known public writable locations.
known_false_positives: Known applications running from these locations for legitimate purposes. Targeting only kerberos (port 88) may significantly reduce noise.
references:
    - https://attack.mitre.org/techniques/T1069/002/
    - https://book.hacktricks.xyz/network-services-pentesting/pentesting-kerberos-88
drilldown_searches:
    - name: View the detection results for - "$src$" and "$dest$"
      search: '%original_detection_search% | search  src = "$src$" dest = "$dest$" user = "$user$"'
      earliest_offset: $info_min_time$
      latest_offset: $info_max_time$
    - name: View risk events for the last 7 days for - "$src$" and "$dest$"
      search: '| from datamodel Risk.All_Risk | search normalized_risk_object IN ("$src$", "$dest$", "$user$") | 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: src
          type: system
          score: 20
          message: The process $process_name$ on $src$ has been communicating with $dest$ on $dest_port$.
        - field: dest
          type: system
          score: 20
          message: The process $process_name$ on $src$ has been communicating with $dest$ on $dest_port$.
        - field: user
          type: user
          score: 20
          message: The process $process_name$ on $src$ has been communicating with $dest$ on $dest_port$.
threat_objects:
    - field: process_name
      type: process_name
analytic_story:
    - Active Directory Discovery
asset_type: Endpoint
mitre_attack_id:
    - T1087.002
    - T1204.002
product:
    - Splunk Enterprise
    - Splunk Enterprise Security
    - Splunk Cloud
category: endpoint
security_domain: endpoint
tests:
    - name: True Positive Test
      attack_data:
        - data: https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/attack_techniques/T1649/certify_abuse/certify_esc1_abuse_sysmon.log
          source: XmlWinEventLog:Microsoft-Windows-Sysmon/Operational
          sourcetype: XmlWinEventLog
      test_type: unit

Stages and Predicates

Stage 1: tstats

| tstats `security_content_summariesonly` count min(_time) as firstTime max(_time) as lastTime values(All_Traffic.process_id) as process_id  from datamodel=Network_Traffic.All_Traffic where All_Traffic.dest_port IN ("88","389","636")  AND All_Traffic.app IN ("*\\users\\*", "*\\programdata\\*", "*\\temp\\*", "*\\Windows\\Tasks\\*", "*\\appdata\\*", "*\\perflogs\\*") by All_Traffic.action All_Traffic.app All_Traffic.dest All_Traffic.dest_ip All_Traffic.dest_port All_Traffic.direction All_Traffic.dvc All_Traffic.protocol All_Traffic.protocol_version All_Traffic.src All_Traffic.src_ip All_Traffic.src_port All_Traffic.transport All_Traffic.user All_Traffic.vendor_product

Stage 2: search

| `drop_dm_object_name(All_Traffic)`

Stage 3: rex

| rex field=app ".*\\\(?<process_name>.*)$"

Stage 4: search

| `security_content_ctime(firstTime)`

Stage 5: search

| `security_content_ctime(lastTime)`

Stage 6: search

| `windows_suspect_process_with_authentication_traffic_filter`

Indicators

Each row is a field, operator, and value that the rule matches. The corpus column counts how many other rules in the catalog look for the same combination: high numbers point to widely-used, community-vetted indicators. Blank or 1 shows that the indicator is specific to this rule.

FieldKindValues
All_Traffic.appin
  • "*\\Windows\\Tasks\\*"
  • "*\\appdata\\*"
  • "*\\perflogs\\*"
  • "*\\programdata\\*"
  • "*\\temp\\*"
  • "*\\users\\*"
All_Traffic.dest_portin
  • "389"
  • "636"
  • "88" corpus 5 (sigma 2, elastic 2, splunk 1)