Detection: Detect Outbound LDAP Traffic

Updated Date: 2024-11-15 ID: 5e06e262-d7cd-4216-b2f8-27b437e18458 Author: Bhavin Patel, Johan Bjerke, Splunk Type: Hunting Product: Splunk Enterprise Security

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.

1
2| tstats `security_content_summariesonly` count min(_time) as firstTime max(_time) as lastTime 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 
3|`drop_dm_object_name("All_Traffic")` 
4| where src_ip != dest_ip 
5| `security_content_ctime(firstTime)`  
6| `security_content_ctime(lastTime)` 
7|`detect_outbound_ldap_traffic_filter`

Data Source

Name Platform Sourcetype Source
Bro N/A 'bro:http:json' 'bro:http:json'

Macros Used

Name Value
security_content_ctime convert timeformat="%Y-%m-%dT%H:%M:%S" ctime($field$)
detect_outbound_ldap_traffic_filter search *
detect_outbound_ldap_traffic_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
T1190 Exploit Public-Facing Application Initial Access
T1059 Command and Scripting Interpreter Execution
Delivery
Installation
DE.AE
CIS 13

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 Risk Event False
This configuration file applies to all detections of type hunting.

Implementation

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

References

Detection Testing

Test Type Status Dataset Source Sourcetype
Validation ✅ Passing N/A N/A N/A
Unit ✅ Passing Dataset pan:traffic pan:traffic
Integration ✅ Passing Dataset pan:traffic pan:traffic

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