Windows: Suspicious LDAP-Attributes Used

Rule ID

PH_Rule_SIGMA_79

Default Status

Enabled

Description

Detects the usage of particular AttributeLDAPDisplayNames, which are known for data exchange via LDAP by the tool LDAPFragger and are additionally not commonly used in companies. This rule is adapted from https://github.com/SigmaHQ/sigma/blob/master/rules/windows/builtin/security/win_security_susp_ldap_dataexchange.yml

Severity

MITRE ATT&CK® Tactics

Command And Control

MITRE ATT&CK® Techniques

T1001.003

Data Obfuscation: Protocol Impersonation

Adversaries may impersonate legitimate protocols or web service traffic to disguise command and control activity and thwart analysis efforts. By impersonating legitimate protocols or web services, adversaries can make their command and control traffic blend in with legitimate network traffic.

https://attack.mitre.org/techniques/T1001/003

Impacts

Server

Data Source

Windows Security Log via OMI or FortiSIEM Agent

Detection

Correlation

Remediation Guidance

No remediation guidance specified

Time Window

If the following pattern or patterns match an ingested event within the given time window in seconds, trigger an incident.

300 seconds

Trigger Conditions

If the following defined pattern/s occur within a 300 second time window.

Filter

SubPattern Definitions

SubPattern Name: Filter

This is the named definition of the event query, this is important if multiple subpatterns are defined to distinguish them.

SubPattern Query

This is the query logic that matches incoming events

eventType="Win-Security-5136" AND propValue REGEXP ".*" AND propName IN ("otherFacsimileTelephoneNumber","primaryInternationalISDNNumber","primaryTelexNumber")

Group by Attributes

This defines how matching events are aggregated, only events with the same matching attribute values are grouped into one unique incident ID

hostName,propName,propValue

Aggregate Constraint

This is most typically a numerical constraint that defines when the rule should trigger an incident

COUNT(*) >= 1

Incident Attribute Mapping

This section defines which fields in matching raw events should be mapped to the incident attributes in the resulting incident.

The available raw event attributes to map are limited to the group by attributes and the aggregate event constraint fields for each subpattern

hostName = Filter.hostName,
propName = Filter.propName,
propValue = Filter.propValue

FortiSIEM Rules