Tenable Research Advisory: Advantech WebAccess Remote Command Execution Still Exploitable

Ryan Seguin

Tenable Researcher Chris Lyne discovered that Advantech WebAccess versions 8.3, 8.3.1 and 8.3.2 are still vulnerable to remote command execution CVE-2017-16720, which was originally disclosed by ZDI in January 2018 and has a public exploit.

Background

Tenable Research’s Chris Lyne has discovered that Advantech WebAccess remains unprotected against a public exploit several months after a patch was released. Vulnerable WebAccess instances remain susceptible to an unauthenticated remote code execution (RCE) attack (CVE-2017-16720). WebAccess versions 8.3, 8.3.1 and 8.3.2 are affected.

On January 4, 2018, ICS-CERT released ICSA-18-004-02A to detail several vulnerabilities reported for Advantech WebAccess. One of the vulnerabilities, CVE-2017-16720, which was also disclosed by the Zero Day Initiative (ZDI), allows an unauthenticated remote attacker to execute arbitrary system commands.

The mitigation section of the ICS-CERT advisory states, “Advantech has released WebAccess Version 8.3 to address the reported vulnerabilities.” In March, two months after the release of the ICS-CERT advisory, a public exploit leveraging CVE-2017-16720 was published to the Exploit Database.

Vulnerability details

This vulnerability allows for remote command execution via the Remote Procedure Call (RPC) protocol over TCP port 4592. By utilizing malicious Distributed Computing Environment / Remote Procedure Calls (DCERPC), the webvrpcs.exe service will pass command line instructions to the host.

The webvrpcs.exe service runs with administrator access rights, which means an attacker can take control of an asset at that privilege level.

Exploitation

There is a publicly available Proof of Concept (PoC) for this vulnerability. Little additional research would be required for an attacker to utilize this PoC against any WebAccess target.

Since this vulnerability was not previously patched, and a public exploit has been available for quite some time, up-to-date assets running WebAccess could have been exploited.

Vendor response

ICS-CERT indicates Advantech has a fix that will be released in September. We will update this section as we get more information, and remediation information becomes available.

Identifying Affected Systems

Tenable has the following plugin available for identifying vulnerable assets.

Plugin ID

Description

117361

Advantech WebAccess/SCADA Network Service Detection

Learn more:

  • Visit the Tenable Techblog on Medium to read researcher Chris Lyne's in-depth story about his work uncovering this vulnerability.
  • Visit the Tenable Research Advisories page to stay up-to-date on security vulnerabilities in third-party software discovered by a dedicated team supported by researchers and engineers at Tenable.

Learn more about Tenable.io, the first Cyber Exposure platform for holistic management of your modern attack surface. Get a free 60-day trial of Tenable.io Vulnerability Management.

Read more >

Published on Sep 10, 2018

People also viewed

Technical Support Engineer

Columbia Maryland United States Columbia Gateway Drive, Columbia, Maryland, United States, 21046 Technical Support Technical Support
Your Role:Tenable is looking for motivated individuals to join our Technical Support Team. The Technical Support Engineer (TSE) is the first contact for all customers when they require technical assistance.  In a time when the next Spectre and Mel...

Sales Development Representative

Singapore Singapore Singapore North Bridge Road, Parkview Square, Singapore, 188788 Lead Generation Sales
Your Role:The Sales Development Representative supports remote sales teams in and is responsible for generating new business via inbound and outbound phone opportunity qualification. Your Opportunity: Perform outbound calling to generate new sales...

Customer Success Manager - APAC Nessus

Singapore Singapore Singapore North Bridge Road, Parkview Square, Singapore, 188788 Customer Success Sales
Your Role:Tenable has an immediate need for a Customer Success Manager who will be responsible for establishing and driving sales activities for our software products within a designated geography. You will be expected to penetrate and prospect na...

Commercial Sales Engineer - Mexico

Mexico City Mexico Mexico Presidenta Masarik, Polanco V Seccion, Mexico City, Mexico, 21045 Sales Engineering Sales
Your Role:Tenable is seeking a Commercial Sales Engineer to assist and drive Business and Technical aspects of strategic selling in your assigned region. You will be partnering with Territory Managers and a strong team of peers to: differentiate t...

Director of Engineering - Shared Services Infrastructure

Columbia Maryland United States Columbia Gateway Drive, Columbia, Maryland, United States, 21046 Sensors Engineering
Your Role:Tenable is looking for a talented and energetic Director of Software Engineering to lead the Shared Services Infrastructure (SSI) development team. The SSI team helps organizations address key challenges of traditional vulnerability scan...

Principal UX Designer

San Jose California United States E Santa Clara St., San Jose, California, United States, 95113 Cloud Platforms Engineering
Your Role:Tenable is looking for an extraordinary Principal UX Designer to join our team. Our group is chartered with creating the next generation of security products while at the same time pioneering unprecedented user experience in the digital ...

We have big plans for continued global growth, and we’re looking for people who are creative, flexible and dedicated to helping us build something great – something that matters.