FortiSIEM Rules

Windows: Browser Started with Remote Debugging

Rule ID


Default Status



Detects browsers starting with the remote debugging flags. Which is a technique often used to perform browser injection attacks. This rule is adapted from







Collection consists of techniques adversaries may use to gather information and the sources information is collected from that are relevant to following through on the adversary's objectives. Frequently, the next goal after collecting data is to steal (exfiltrate) the data. Common target sources include various drive types, browsers, audio, video, and email. Common collection methods include capturing screenshots and keyboard input.

MITRE ATT&CK® Techniques


Man in the Browser

Adversaries can take advantage of security vulnerabilities and inherent functionality in browser software to change content, modify behavior, and intercept information as part of various man in the browser techniques. A specific example is when an adversary injects software into a browser that allows an them to inherit cookies, HTTP sessions, and SSL client certificates of a user and use the browser as a way to pivot into an authenticated intranet. Browser pivoting requires the SeDebugPrivilege and a high-integrity process to execute. Browser traffic is pivoted from the adversary's browser through the user's browser by setting up an HTTP proxy which will redirect any HTTP and HTTPS traffic.



Data Source

Windows Sysmon via FortiSIEM Agent



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.


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-Sysmon-1-Create-Process" AND (command REGEXP ".* --remote-debugging-.*" OR (procName REGEXP "\\firefox\.exe$" AND command REGEXP ".* -start-debugger-server.*"))

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

command = Filter.command,
hostName = Filter.hostName,
procName = Filter.procName