Detection: Detect Port Security Violation

EXPERIMENTAL DETECTION

This detection status is set to experimental. The Splunk Threat Research team has not yet fully tested, simulated, or built comprehensive datasets for this detection. As such, this analytic is not officially supported. If you have any questions or concerns, please reach out to us at research@splunk.com.

Updated Date: 2024-10-17 ID: 2de3d5b8-a4fa-45c5-8540-6d071c194d24 Author: Mikael Bjerkeland, Splunk Type: TTP Product: Splunk Enterprise Security

Description

The following analytic detects port security violations on Cisco switches. It leverages logs from Cisco network devices, specifically looking for events with mnemonics indicating port security violations. This activity is significant because it indicates an unauthorized device attempting to connect to a secured port, potentially bypassing network access controls. If confirmed malicious, this could allow an attacker to gain unauthorized access to the network, leading to data exfiltration, network disruption, or further lateral movement within the environment.

Search

1`cisco_networks` (facility="PM" mnemonic="ERR_DISABLE" disable_cause="psecure-violation") OR (facility="PORT_SECURITY" mnemonic="PSECURE_VIOLATION" OR mnemonic="PSECURE_VIOLATION_VLAN") 
2| eval src_interface=src_int_prefix_long+src_int_suffix 
3| stats min(_time) AS firstTime max(_time) AS lastTime values(disable_cause) AS disable_cause values(src_mac) AS src_mac values(src_vlan) AS src_vlan values(action) AS action count by host src_interface 
4| `security_content_ctime(firstTime)` 
5| `security_content_ctime(lastTime)` 
6| `detect_port_security_violation_filter`

Data Source

No data sources specified for this detection.

Macros Used

Name	Value
cisco_networks	`eventtype=cisco_ios`
detect_port_security_violation_filter	`search *`

detect_port_security_violation_filter is an empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.

Annotations

- MITRE ATT&CK

+ Kill Chain Phases

+ NIST

+ CIS

- Threat Actors

ID	Technique	Tactic
T1200	Hardware Additions	Initial Access
T1498	Network Denial of Service	Impact
T1557	Adversary-in-the-Middle	Collection
T1557.002	ARP Cache Poisoning	Credential Access

KillChainPhase.ACTIONS_ON_OBJECTIVES

KillChainPhase.DELIVERY

KillChainPhase.EXPLOITAITON

NistCategory.DE_CM

Cis18Value.CIS_13

DarkVishnya

APT28

Kimsuky

Cleaver

LuminousMoth

Default Configuration

This detection is configured by default in Splunk Enterprise Security to run with the following settings:

Setting	Value
Disabled	true
Cron Schedule	`0 * * * *`
Earliest Time	`-70m@m`
Latest Time	`-10m@m`
Schedule Window	`auto`
Creates Notable	Yes
Rule Title	`%name%`
Rule Description	`%description%`
Notable Event Fields	user, dest
Creates Risk Event	True

This configuration file applies to all detections of type TTP. These detections will use Risk Based Alerting and generate Notable Events.

Implementation

This search uses a standard SPL query on logs from Cisco Network devices. The network devices must be configured with Port Security and Error Disable for this to work (see https://www.cisco.com/c/en/us/td/docs/switches/lan/catalyst4500/12-2/25ew/configuration/guide/conf/port_sec.html) and log with a severity level of minimum "5 - notification". The search also requires that the Cisco Networks Add-on for Splunk (https://splunkbase.splunk.com/app/1467) is used to parse the logs from the Cisco network devices.

Known False Positives

This search might be prone to high false positives if you have malfunctioning devices connected to your ethernet ports or if end users periodically connect physical devices to the network.

Associated Analytic Story

Router and Infrastructure Security

Risk Based Analytics (RBA)

Risk Message	Risk Score	Impact	Confidence
tbd	25	50	50

The Risk Score is calculated by the following formula: Risk Score = (Impact * Confidence/100). Initial Confidence and Impact is set by the analytic author.

Detection Testing

Test Type	Status	Dataset	Source	Sourcetype
Validation	Not Applicable	N/A	N/A	N/A
Unit	❌ Failing	N/A	`N/A`	`N/A`
Integration	❌ Failing	N/A	`N/A`	`N/A`

Replay any dataset to Splunk Enterprise by using our replay.py tool or the UI. Alternatively you can replay a dataset into a Splunk Attack Range

Source: GitHub | Version: 4