T0819_exploit-public-facing-application

T0819 Exploit Public-Facing Application

High-Level Description

Adversaries may leverage weaknesses to exploit internet-facing software for initial access into an industrial network. Internet-facing software may be user applications, underlying networking implementations, an assets operating system, weak defenses, etc. Targets of this technique may be intentionally exposed for the purpose of remote management and visibility.

An adversary may seek to target public-facing applications as they may provide direct access into an ICS environment or the ability to move into the ICS network. Publicly exposed applications may be found through online tools that scan the internet for open ports and services. Version numbers for the exposed application may provide adversaries an ability to target specific known vulnerabilities. Exposed control protocol or remote access ports found in Commonly Used Port may be of interest by adversaries.

Kill Chain Phase

• Initial Access (TA0108)

Platforms: ICS

What to Check

• Identify if Exploit Public-Facing Application technique is applicable to target ICS environment
• Check ICS/SCADA systems for indicators of Exploit Public-Facing Application
• Verify mitigations are bypassed or absent (6 known mitigations)
• Assess detection coverage (1 detection strategies)

How to Test

Identify Attack Surface

Determine if the target ICS/SCADA environment is susceptible to Exploit Public-Facing Application by examining operational technology systems and network architecture.

Assess Existing Defenses

Review whether mitigations for T0819 are in place. If defenses are absent or misconfigured, this technique may be exploitable in the ICS environment.

Remediation Guide

M0951 Update Software

Regularly scan externally facing systems for vulnerabilities and establish procedures to rapidly patch systems when critical vulnerabilities are discovered through scanning and public disclosure.

M0916 Vulnerability Scanning

Regularly scan externally facing systems for vulnerabilities and establish procedures to rapidly patch systems when critical vulnerabilities are discovered through scanning and public disclosure.

M0950 Exploit Protection

Web Application Firewalls may be used to limit exposure of applications to prevent exploit traffic from reaching the application.

M0926 Privileged Account Management

Use least privilege for service accounts.

M0948 Application Isolation and Sandboxing

Application isolation will limit the other processes and system features an exploited target can access. Examples of built in features are software restriction policies, AppLocker for Windows, and SELinux or AppArmor for Linux.

M0930 Network Segmentation

Segment externally facing servers and services from the rest of the network with a DMZ or on separate hosting infrastructure.

Detection

Detection of Exploit Public-Facing Application

Risk Assessment

CWE Categories

References

• MITRE ATT&CK ICS - T0819