Moxa OnCell Security Vulnerabilities

OVERVIEW

Independent researcher Maxim Rupp has identified authorization bypass and disclosed OS commanding vulnerabilities in Moxa’s OnCell Security Software. Moxa has produced a new version to mitigate these vulnerabilities.

These vulnerabilities could be exploited remotely.

AFFECTED PRODUCTS

The following Moxa OnCell versions are affected:

• OnCellG3470A-LTE,
• AWK-1131A/3131A/4131A Series,
• AWK-3191 Series,
• AWK-5232/6232 Series,
• AWK-1121/1127 Series,
• WAC-1001 V2 Series,
• WAC-2004 Series,
• AWK-3121-M12-RTG Series,
• AWK-3131-M12-RCC Series,
• AWK-5232-M12-RCC Series,
• TAP-6226 Series,
• AWK-3121/4121 Series,
• AWK-3131/4131 Series, and
• AWK-5222/6222 Series.

IMPACT

An unauthorized user could download files by accessing a specific URL. An unauthenticated user is able to execute arbitrary command by web console.

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.

BACKGROUND

Moxa is a Taiwan-based company that maintains offices in several countries around the world, including the US, UK, India, Germany, France, China, Russia, and Brazil.

The affected product, OnCell Security Software, is cellular IP gateways that can connect serial or Ethernet devices to a cellular network. According to Moxa, OnCell Security Software is deployed across several sectors including Commercial Facilities, Critical Manufacturing, Energy, and Transportation Systems. Moxa estimates that this product is used primarily in Asia and Europe.

VULNERABILITY CHARACTERIZATION

VULNERABILITY OVERVIEW

Any user is able to download log files by accessing a specific URL.

CVE-2016-8362NVD, https://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2016-8362, NIST uses this advisory to create the CVE web site report. This web site will be active sometime after publication of this advisory. has been assigned to this vulnerability. A CVSS v3 base score of 6.5 has been assigned; the CVSS vector string is (AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N).CVSS Calculator, https://www.first.org/cvss/calculator/3.0#CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N, web site last accessed November 03, 2016.

User is able to execute arbitrary OS commands on the server.

CVE-2016-8363NVD, https://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2016-8363, NIST uses this advisory to create the CVE web site report. This web site will be active sometime after publication of this advisory. has been assigned to this vulnerability. A CVSS v3 base score of 9.1 has been assigned; the CVSS vector string is (AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H).CVSS Calculator, https://www.first.org/cvss/calculator/3.0#CVSS:3.0/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H, web site last accessed November 03, 2016.

VULNERABILITY DETAILS

EXPLOITABILITY

These vulnerabilities could be exploited remotely.

EXISTENCE OF EXPLOIT

No known public exploits specifically target these vulnerabilities.

DIFFICULTY

An attacker with a low skill would be able to exploit these vulnerabilities.

MITIGATION

Moxa recommends that users disable HTTP/HTTPS after completing required configuration through web browser interface. Users can access via SNMP to enable HTTP/HTTPS if needed. If remote control or monitoring is required, users should enable “IP Protocol Filter” feature of OnCell/AWK products to prevent any unauthorized access to the administrative web management interface.

Moxa has developed the following patch plan.

No future updates are planned for the following models:

• TAP-6226 Series,
• AWK-3121/4121 Series,
• AWK-3131/4131 Series, and
• AWK-5222/6222 Series.

Users should contact Moxa if further assistance is needed for these models at:

https://www.moxa.com/en/support/support/technical-support.

ICS-CERT recommends that users take defensive measures to minimize the risk of exploitation of these vulnerabilities. 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.

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. 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 ICS‑CERT Technical Information Paper, ICS-TIP-12-146-01B--Targeted Cyber Intrusion Detection and Mitigation Strategies, that is available for download from the ICS-CERT web site.

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.