FortiSIEM Rules

Windows: Possible PetitPotam Coerce Authentication Attempt

Rule ID


Default Status



Detect PetitPotam coerced authentication activity. PetitPotam is a tool that can coerce Windows hosts to authenticate to other machines. By manipulating the data being exchanged between the attacker and the server, the attacker can force the server to authenticate the attacker as a legitimate user, in what’s known as an NTLM Relay attack. This rule is adapted from






Credential Access

Credential Access consists of techniques for stealing credentials like account names and passwords. Techniques used to get credentials include keylogging or credential dumping. Using legitimate credentials can give adversaries access to systems, make them harder to detect, and provide the opportunity to create more accounts to help achieve their goals.

MITRE ATT&CK® Techniques


Forced Authentication

Adversaries may gather credential material by invoking or forcing a user to automatically provide authentication information through a mechanism in which they can intercept.The Server Message Block (SMB) protocol is commonly used in Windows networks for authentication and communication between systems for access to resources and file sharing. When a Windows system attempts to connect to an SMB resource it will automatically attempt to authenticate and send credential information for the current user to the remote system.



Data Source

Windows Security Log via OMI or FortiSIEM Agent



Remediation Guidance

Determine if this was an authorized penetration testing activity. Otherwise, there is no reason for this activity to be occurring. The host should be quarantined and investigated immediately. Collect the process hash and check for malware match. Investigate what other incidents are occurring on that host during that time frame.

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.


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-5145" AND fileName REGEXP "^\\\\" AND fileName REGEXP "\\IPC\$$" AND targetName="lsarpc" AND user="ANONYMOUS LOGON"

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


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

fileName = Filter.fileName,
hostName = Filter.hostName,
targetName = Filter.targetName,
user = Filter.user