splunk_escuAnomaly

Linux Auditd System Network Configuration Discovery

The following analytic detects suspicious system network configuration discovery activities, which may indicate an adversary's attempt to gather information about the network environment. Such actions typically involve commands or tools used to identify network interfaces, routing tables, and active connections. Detecting these activities is crucial, as they often precede more targeted attacks like lateral movement or data exfiltration. By identifying unusual or unauthorized network discovery efforts, this analytic helps security teams to swiftly detect and respond to potential reconnaissance operations, mitigating the risk of further compromise.

MITRE ATT&CK

T1016

Detection Query

`linux_auditd` type=SYSCALL comm IN ("arp", "ifconfig", "ip", "netstat", "firewall-cmd", "ufw", "iptables", "ss", "route")
  | bucket _time span=15m
  | rename host as dest
  | stats dc(comm) as unique_commands, values(comm) as comm, values(exe) as exe, values(syscall) as syscall, values(uid) as uid, values(ppid) as ppid, values(pid) as pid, count, min(_time) as firstTime, max(_time) as lastTime
    BY success dest
  | where unique_commands >= 4
  | `security_content_ctime(firstTime)`
  | `security_content_ctime(lastTime)`
  | `linux_auditd_system_network_configuration_discovery_filter`

Author

Teoderick Contreras, Splunk

Created

2026-03-10

Data Sources

Linux Auditd Syscall

References

https://www.splunk.com/en_us/blog/security/deep-dive-on-persistence-privilege-escalation-technique-and-detection-in-linux-platform.html

Tags

Linux Living Off The LandLinux Privilege EscalationLinux Persistence TechniquesCompromised Linux Host

Raw Content

name: Linux Auditd System Network Configuration Discovery
id: 5db16825-81bd-4923-a8d6-d6a13a59832a
version: 7
date: '2026-03-10'
author: Teoderick Contreras, Splunk
status: production
type: Anomaly
description: The following analytic detects suspicious system network configuration discovery activities, which may indicate an adversary's attempt to gather information about the network environment. Such actions typically involve commands or tools used to identify network interfaces, routing tables, and active connections. Detecting these activities is crucial, as they often precede more targeted attacks like lateral movement or data exfiltration. By identifying unusual or unauthorized network discovery efforts, this analytic helps security teams to swiftly detect and respond to potential reconnaissance operations, mitigating the risk of further compromise.
data_source:
    - Linux Auditd Syscall
search: |-
    `linux_auditd` type=SYSCALL comm IN ("arp", "ifconfig", "ip", "netstat", "firewall-cmd", "ufw", "iptables", "ss", "route")
      | bucket _time span=15m
      | rename host as dest
      | stats dc(comm) as unique_commands, values(comm) as comm, values(exe) as exe, values(syscall) as syscall, values(uid) as uid, values(ppid) as ppid, values(pid) as pid, count, min(_time) as firstTime, max(_time) as lastTime
        BY success dest
      | where unique_commands >= 4
      | `security_content_ctime(firstTime)`
      | `security_content_ctime(lastTime)`
      | `linux_auditd_system_network_configuration_discovery_filter`
how_to_implement: To implement this detection, the process begins by ingesting auditd data, that consist SYSCALL, TYPE, EXECVE and PROCTITLE events, which captures command-line executions and process details on Unix/Linux systems. These logs should be ingested and processed using Splunk Add-on for Unix and Linux (https://splunkbase.splunk.com/app/833), which is essential for correctly parsing and categorizing the data. The next step involves normalizing the field names  to match the field names set by the Splunk Common Information Model (CIM) to ensure consistency across different data sources and enhance the efficiency of data modeling. This approach enables effective monitoring and detection of linux endpoints where auditd is deployed
known_false_positives: Administrator or network operator can use this application for automation purposes. Please update the filter macros to remove false positives.
references:
    - https://www.splunk.com/en_us/blog/security/deep-dive-on-persistence-privilege-escalation-technique-and-detection-in-linux-platform.html
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 ("$dest$") starthoursago=168  | 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: $info_min_time$
      latest_offset: $info_max_time$
rba:
    message: A SYSCALL - [$comm$] event was executed on host - [$dest$] to discover system network configuration.
    risk_objects:
        - field: dest
          type: system
          score: 20
    threat_objects: []
tags:
    analytic_story:
        - Linux Living Off The Land
        - Linux Privilege Escalation
        - Linux Persistence Techniques
        - Compromised Linux Host
    asset_type: Endpoint
    mitre_attack_id:
        - T1016
    product:
        - Splunk Enterprise
        - Splunk Enterprise Security
        - Splunk Cloud
    security_domain: endpoint
tests:
    - name: True Positive Test
      attack_data:
        - data: https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/attack_techniques/T1016/linux_auditd_net_tool_new/linux_auditd_net_tool_bucket_new.log
          source: auditd
          sourcetype: auditd