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Description

Malicious actors often abuse misconfigured LDAP servers or applications that use the LDAP servers in organizations. Outbound LDAP traffic should not be allowed outbound through your perimeter firewall. This search will help determine if you have any LDAP connections to IP addresses outside of private (RFC1918) address space.

  • Type: Hunting
  • Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud
  • Datamodel: Network_Traffic
  • Last Updated: 2021-12-13
  • 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
  • Command & Control
  • Actions on Objectives
NIST
  • PR.DS
  • PR.PT
  • DE.AE
  • DE.CM
CIS20
  • CIS 12
  • CIS 13
CVE
ID Summary CVSS
CVE-2021-44228 Apache Log4j2 2.0-beta9 through 2.15.0 (excluding security releases 2.12.2, 2.12.3, and 2.3.1) JNDI features used in configuration, log messages, and parameters do not protect against attacker controlled LDAP and other JNDI related endpoints. An attacker who can control log messages or log message parameters can execute arbitrary code loaded from LDAP servers when message lookup substitution is enabled. From log4j 2.15.0, this behavior has been disabled by default. From version 2.16.0 (along with 2.12.2, 2.12.3, and 2.3.1), this functionality has been completely removed. Note that this vulnerability is specific to log4j-core and does not affect log4net, log4cxx, or other Apache Logging Services projects. 9.3
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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

You must be ingesting Zeek DNS and Zeek Conn data into Splunk. Zeek data should also be getting ingested in JSON format and should be mapped to the Network Traffic datamodels that are in use for this search.

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: 1