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Description

The following analytic identifies outbound LDAP traffic to external IP addresses. It leverages the Network_Traffic data model to detect connections on ports 389 or 636 that are not directed to private IP ranges (RFC1918). This activity is significant because outbound LDAP traffic can indicate potential data exfiltration or unauthorized access attempts. If confirmed malicious, attackers could exploit this to access sensitive directory information, leading to data breaches or further network compromise.

  • Type: Hunting
  • Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud
  • Datamodel: Network_Traffic
  • Last Updated: 2024-05-21
  • Author: Bhavin Patel, Johan Bjerke, Splunk
  • ID: 5e06e262-d7cd-4216-b2f8-27b437e18458

Annotations

ATT&CK

ATT&CK

ID Technique Tactic
T1190 Exploit Public-Facing Application Initial Access
T1059 Command and Scripting Interpreter Execution
Kill Chain Phase
  • Delivery
  • Installation
NIST
  • DE.AE
CIS20
  • CIS 13
CVE 


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| tstats earliest(_time) as earliest_time latest(_time) as latest_time values(All_Traffic.dest_ip) as dest_ip from datamodel=Network_Traffic.All_Traffic where All_Traffic.dest_port = 389 OR All_Traffic.dest_port = 636 AND NOT (All_Traffic.dest_ip = 10.0.0.0/8 OR All_Traffic.dest_ip=192.168.0.0/16 OR All_Traffic.dest_ip = 172.16.0.0/12) by All_Traffic.src_ip All_Traffic.dest_ip 
|`drop_dm_object_name("All_Traffic")` 
| where src_ip != dest_ip 
| `security_content_ctime(latest_time)`  
| `security_content_ctime(earliest_time)` 
|`detect_outbound_ldap_traffic_filter`

Macros

The SPL above uses the following Macros:

:information_source: detect_outbound_ldap_traffic_filter is a empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.

Required fields

List of fields required to use this analytic.

  • _time
  • All_Traffic.dest_ip
  • All_Traffic.dest_port
  • All_Traffic.src_ip

How To Implement

In order to properly run this search, Splunk needs to ingest data from Next Generation Firewalls like Palo Alto Networks Firewalls or other network control devices that mediate the traffic allowed into an environment. The search requires the Network_Traffic data model to be populated.

Known False Positives

Unknown at this moment. Outbound LDAP traffic should not be allowed outbound through your perimeter firewall. Please check those servers to verify if the activity is legitimate.

Associated Analytic Story

RBA

Risk Score Impact Confidence Message
56.0 70 80 An outbound LDAP connection from $src_ip$ in your infrastructure connecting to dest ip $dest_ip$

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

Reference

Test Dataset

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 | version: 2