Windows: Potential MSTSC Shadowing Activity

Rule ID

PH_Rule_SIGMA_495

Default Status

Enabled

Description

Detects RDP session hijacking by using MSTSC shadowing. This rule is adapted from https://github.com/SigmaHQ/sigma/blob/master/rules/windows/process_creation/proc_creation_win_mstsc_rdp_hijack_shadowing.yml

Severity

MITRE ATT&CK® Tactics

Lateral Movement

Lateral Movement consists of techniques that adversaries use to enter and control remote systems on a network. Following through on their primary objective often requires exploring the network to find their target and subsequently gaining access to it. Reaching their objective often involves pivoting through multiple systems and accounts to gain. Adversaries might install their own remote access tools to accomplish Lateral Movement or use legitimate credentials with native network and operating system tools, which may be stealthier.

https://attack.mitre.org/tactics/TA0008

MITRE ATT&CK® Techniques

T1563.002

Remote Service Session Hijacking: RDP Hijacking

Adversaries may hijack a legitimate user's remote desktop session to move laterally within an environment. Remote desktop allows a user to log into an interactive session with a system desktop graphical user interface on a remote system. With System permissions and using Terminal Services Console, `c:\windows\system32\tscon.exe [session number to be stolen]`, an adversary can hijack a session without the need for credentials or prompts to the user. This can be done remotely or locally and with active or disconnected sessions. All of this can be done by using native Windows commands

https://attack.mitre.org/techniques/T1563/002

Impacts

Server

Data Source

Windows Sysmon via 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-Sysmon-1-Create-Process" AND command REGEXP ".*noconsentprompt.*" AND command REGEXP ".*shadow:.*"

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

command,hostName

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

FortiSIEM Rules