WECON PI Studio

1. EXECUTIVE SUMMARY

• CVSS v3 9.8
• ATTENTION: Exploitable remotely/low skill level to exploit
• Vendor: WECON Technology Co., Ltd. (WECON)
• Equipment: PI Studio
• Vulnerabilities: Stack-based Buffer Overflow, Out-of-Bounds Write, Information Exposure Through XML External Entity Reference, Out-of-Bounds Read

2. RISK EVALUATION

Successful exploitation of these vulnerabilities may allow remote code execution, execution of code in the context of an administrator, read past the end of an allocated object or allow an attacker to disclose sensitive information under the context of administrator.

3. TECHNICAL DETAILS

3.1 AFFECTED PRODUCTS

The following versions of PI Studio, a HMI project programmer, are affected:

• PI Studio HMI: Versions 4.1.9 and prior,
• PI Studio Versions 4.2.34 and prior.

3.2 VULNERABILITY OVERVIEW

3.2.1    STACK-BASED BUFFER OVERFLOW CWE-121

A stack-based buffer overflow vulnerability has been identified, which may allow remote code execution.

CVE-2018-14818 has been assigned to this vulnerability. A CVSS v3 base score of 9.8 has been calculated; the CVSS vector string is (AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H).

3.2.2    OUT-OF-BOUNDS WRITE CWE-787

The affected product parses files and passes invalidated user data to an unsafe method call, which may allow code to be executed in the context of an administrator.

CVE-2018-14810 has been assigned to this vulnerability. A CVSS v3 base score of 8.8 has been calculated; the CVSS vector string is (AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H).

3.2.3    INFORMATION EXPOSURE THROUGH XML EXTERNAL ENTITY REFERENCE CWE-611

When parsing project files, the XMLParser that ships with Wecon PIStudio is vulnerable to a XML external entity injection attack, which may allow sensitive information disclosure.

CVE-2018-17889 has been assigned to this vulnerability. A CVSS v3 base score of 5.3 has been assigned; the CVSS vector string is (AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:N/A:N).

3.2.4    OUT-OF-BOUNDS READ CWE-125

The affected product lacks proper validation of user-supplied data, which may result in a read past the end of an allocated object.

CVE-2018-14814 has been assigned to this vulnerability. A CVSS v3 base score of 4.3 has been calculated; the CVSS vector string is (AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:N).

3.3 BACKGROUND

• CRITICAL INFRASTRUCTURE SECTORS: Critical Manufacturing, Energy, Water and Wastewater Systems
• COUNTRIES/AREAS DEPLOYED: Worldwide
• COMPANY HEADQUARTERS LOCATION: China

3.4 RESEARCHER

Mat Powell and Natnael Samson (Natti), working with Trend Micro’s Zero Day Initiative, reported these vulnerabilities to NCCIC.

4. MITIGATIONS

WECON has verified the vulnerabilities but has not yet released an updated version. NCCIC is currently working with WECON and will update the advisory once an updated version is released.

NCCIC recommends users take defensive measures to minimize the risk of exploitation of this vulnerability. Specifically, users should:

• Minimize network exposure for all control system devices and/or systems, and ensure that they are not accessible from the Internet.
• Locate control system networks and remote devices behind firewalls, and isolate them from the business network.
• When remote access is required, use secure methods, such as Virtual Private Networks (VPNs), recognizing that VPNs may have vulnerabilities and should be updated to the most current version available. Also recognize that VPN is only as secure as the connected devices.

NCCIC reminds organizations to perform proper impact analysis and risk assessment prior to deploying defensive measures.

NCCIC also provides a section for control systems security recommended practices on the ICS-CERT web page. Several recommended practices are available for reading and download, including Improving Industrial Control Systems Cybersecurity with Defense-in-Depth Strategies.

Additional mitigation guidance and recommended practices are publicly available on the ICS-CERT website in the Technical Information Paper, ICS-TIP-12-146-01B–Targeted Cyber Intrusion Detection and Mitigation Strategies.

Organizations observing any suspected malicious activity should follow their established internal procedures and report their findings to NCCIC for tracking and correlation against other incidents.

No known public exploits specifically target these vulnerabilities.