This updated advisory is a follow-up to the original advisory titled ICSA-16-173-01 Advantech WebAccess ActiveX Vulnerabilities that was published June 21, 2016, on the NCCIC/ICS-CERT web site.
Zhou Yu of Acorn Network Security and ZDI (Zero Day Initiative) have identified vulnerabilities in Advantechβs WebAccess. Advantech has produced a new version to mitigate these vulnerabilities. Zhou Yu has tested the new version to validate that it resolves the vulnerabilities.
Advantech reports that the vulnerabilities affect the following versions of WebAccess:
The vulnerabilities could allow an attacker who successfully exploits them to insert and run arbitrary code on an affected system.
Impact to individual organizations depends on many factors that are unique to each organization. NCCIC/ICS-CERT recommends that organizations evaluate the impact of these vulnerabilities based on their operational environment, architecture, and product implementation.
Advantech is based in Taiwan and has distribution offices in 21 countries worldwide.
The affected product, WebAccess, formerly known as BroadWin WebAccess, is a web-based SCADA and human-machine interface (HMI) product. According to Advantech, WebAccess is deployed across several sectors including Commercial Facilities, Critical Manufacturing, Energy, and Government Facilities. Advantech estimates that this product is used globally.
Several ActiveX controls are intended for restricted use, but have been marked as safe-for-scripting.
CVE-2016-4525b has been assigned to these vulnerabilities. A CVSS v3 base score of 6.6 has been calculated; the CVSS vector string is (AV:L/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:N).c
A specially crafted DLL file can cause a buffer overflow.
CVE-2016-4528e has been assigned to these vulnerabilities. A CVSS v3 base score of 5.0 has been calculated; the CVSS vector string is (AV:L/AC:L/PR:L/UI:R/S:U/C:N/I:N/A:H).f
A properly authenticated administrator can view passwords for other administrators.
CVE-2016-5810h has been assigned to this vulnerability. A CVSS v3 base score of 5.7 has been calculated; the CVSS vector string is (AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:N/A:N).i
These vulnerabilities are not exploitable remotely and cannot be exploited without user interaction. The exploit is only triggered when a local user runs the vulnerable application, which in certain scenarios can cause it to load a DLL file from an untrusted source.
No known public exploits specifically target these vulnerabilities.
Crafting a working exploit for these vulnerabilities would be difficult. Social engineering is required to convince the user to accept a malformed DLL file. Additional user interaction is needed to load the malformed file. This decreases the likelihood of a successful exploit.
Advantech has released a new version of WebAccess, Version 8.1_20160519, to address the reported vulnerabilities. This new version is available on the Advantech web site at the following location:
<http://www.advantech.com/industrial-automation/webaccess>
ICS-CERT recommends that users take defensive measures to protect themselves from social engineering attacks. Specifically, users should:
ICS-CERT reminds organizations to perform proper impact analysis and risk assessment prior to deploying defensive measures.
ICS-CERT also provides a section for control systems security recommended practices on the ICS-CERT web page at: http://ics-cert.us-cert.gov/content/recommended-practices. 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 in the ICSβCERT Technical Information Paper, ICS-TIP-12-146-01BβTargeted Cyber Intrusion Detection and Mitigation Strategies, that is available for download from the ICS-CERT web site (http://ics-cert.us-cert.gov/).
Organizations observing any suspected malicious activity should follow their established internal procedures and report their findings to ICS-CERT for tracking and correlation against other incidents.
Contact Information
For any questions related to this report, please contact the CISA at:
Email: [email protected]
Toll Free: 1-888-282-0870
For industrial control systems cybersecurity information: https://us-cert.cisa.gov/ics
or incident reporting: https://us-cert.cisa.gov/report
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