Detection: Detect Outbound LDAP Traffic

Updated Date: 2024-10-17 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
KillChainPhase.DELIVERY
KillChainPhase.INSTALLATION
NistCategory.DE_AE
Cis18Value.CIS_13
APT28
APT29
APT39
APT41
APT5
Agrius
Axiom
BackdoorDiplomacy
BlackTech
Blue Mockingbird
Cinnamon Tempest
Dragonfly
Earth Lusca
Ember Bear
FIN13
FIN7
Fox Kitten
GALLIUM
GOLD SOUTHFIELD
HAFNIUM
INC Ransom
Ke3chang
Kimsuky
Magic Hound
Moses Staff
MuddyWater
Play
Rocke
Sandworm Team
Threat Group-3390
ToddyCat
Volatile Cedar
Volt Typhoon
Winter Vivern
menuPass
APT19
APT32
APT37
APT39
Dragonfly
FIN5
FIN6
FIN7
Fox Kitten
Ke3chang
OilRig
Saint Bear
Stealth Falcon
Whitefly
Windigo
Winter Vivern

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

Risk Based Analytics (RBA)

Risk Message Risk Score Impact Confidence
An outbound LDAP connection from $src_ip$ in your infrastructure connecting to dest ip $dest_ip$ 56 70 80
The Risk Score is calculated by the following formula: Risk Score = (Impact * Confidence/100). Initial Confidence and Impact is set by the analytic author.

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: 3