Windows: PUA - Chisel Tunneling Tool Execution

Rule ID

PH_Rule_SIGMA_2461

Default Status

Enabled

Description

Detects usage of the Chisel tunneling tool via the commandline arguments. This rule is adapted from https://github.com/SigmaHQ/sigma/blob/master/rules/windows/process_creation/proc_creation_win_pua_chisel.yml

Severity

MITRE ATT&CK® Tactics

Command And Control

MITRE ATT&CK® Techniques

T1090.001

Proxy: Internal Proxy

Adversaries may use an internal proxy to direct command and control traffic between two or more systems in a compromised environment. Many tools exist that enable traffic redirection through proxies or port redirection, including HTRAN, ZXProxy, and ZXPortMap. Adversaries use internal proxies to manage command and control communications inside a compromised environment, to reduce the number of simultaneous outbound network connections, to provide resiliency in the face of connection loss, or to ride over existing trusted communications paths between infected systems to avoid suspicion. Internal proxy connections may use common peer-to-peer (p2p) networking protocols, such as SMB, to better blend in with the environment.

https://attack.mitre.org/techniques/T1090/001

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 (procName REGEXP "\\chisel\.exe$" OR (command REGEXP ".*exe client .*|.*exe server .*" AND command REGEXP ".* r:.*|.*-reverse.*|.*-socks5.*|.*-tls-skip-verify .*|.*:127\.0\.0\.1:.*|.*:socks.*"))

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,procName

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

FortiSIEM Rules