Advantech EKI Vulnerabilities (Update B)

OVERVIEW

This updated advisory is a follow-up to the updated advisory titled ICSA-15-344-01A Advantech EKI Vulnerabilities that was published December 15, 2015, on the NCCIC/ICS-CERT web site.

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HD Moore of Rapid7 identified several vulnerabilities in Advantech’s EKI. Advantech has released updated firmware to mitigate these vulnerabilities.

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These vulnerabilities could be exploited remotely. Exploits that target these vulnerabilities are known to be publicly available.

AFFECTED PRODUCTS

Advantech reports that the vulnerability affects the following products:

• EKI-132x platform devices.

IMPACT

Exploitation of these vulnerabilities may allow an attacker to execute arbitrary code, to obtain private keys, or to impersonate the authenticated user and perform a man-in-the-middle attack.

Impact to individual organizations depends on many factors that are unique to each organization. ICS-CERT recommends that organizations evaluate the impact of these vulnerabilities based on their operational environment, architecture, and product implementation.

BACKGROUND

Advantech is based in Taiwan and has distribution offices in 21 countries worldwide.

The EKI-1200 series Modbus gateways are bidirectional gateways for integrating Modbus/RTU and Modbus/ASCII serial devices to TCP/IP networked-based devices. These products are deployed in industrial automation globally.

VULNERABILITY CHARACTERIZATION

VULNERABILITY OVERVIEW

OS COMMAND INJECTIONa

GNU Bash Versions 1.14 through 4.3 contain a flaw that processes commands placed after function definitions in the added environment variable, allowing remote attackers to execute arbitrary code via a crafted environment, which enables network-based exploitation. This vulnerability is also known as “ShellShock.”b

CVE-2014-6271c has been assigned to this vulnerability. A CVSS v3 base score of 10.0 has been assigned; the CVSS vector string is (AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H).d

IMPROPER RESTRICTION OF OPERATIONS WITHIN THE BOUNDS OF A MEMORY BUFFERe

Advantech EKI uses the OpenSSL cryptographic library and transport layer security (TLS) implementation Version 1.0.1, which is known to be vulnerable to the Heartbleed vulnerability.f

CVE-2014-0160g has been assigned to this vulnerability. A CVSS v3 base score of 7.5 has been assigned; the CVSS vector string is (AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N).h

IMPROPER RESTRICTION OF OPERATIONS WITHIN THE BOUNDS OF A MEMORY BUFFERi

Stack-based buffer overflow in the get_packet method in socket.c in dhcpcd 3.2.3 allows remote attackers to cause a denial of service (crash) and possibly execute arbitrary code via a long packet.

CVE-2012-2152j has been assigned to this vulnerability. A CVSS v3 base score of 7.3 has been assigned; the CVSS vector string is (AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L).k

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AUTHENTICATION BYPASS ISSUESl

An attacker is able to bypass authentication to access the device.

CVE-2015-7938m has been assigned to this vulnerability. A CVSS v3 base score of 9.8 has been assigned; the CVSS vector string is (AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H).n

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VULNERABILITY DETAILS

EXPLOITABILITY

These vulnerabilities could be exploited remotely.

EXISTENCE OF EXPLOIT

Exploits that target these vulnerabilities are publicly available.

DIFFICULTY

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

MITIGATION

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Advantech has released a firmware update to mitigate these vulnerabilities in the EKI-132* product line on December 31, 2015. Users may download the latest firmware from the following location on Advantech’s web site:

http://support.advantech.com.tw/Support/SearchResult.aspx?keyword=EKI-132*&searchtabs=Firmware

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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 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 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 (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.

• aCWE-78: Improper Neutralization of Special Elements used in an OS Command (‘OS Command Injection’), http://cwe.mitre.org/data/definitions/78.html, web site last accessed December 10, 2015.
• bUS-CERT Alert (TA14-268A) - GNU Bourne-Again Shell (Bash) ‘Shellshock’ Vulnerability, https://www.us-cert.gov/ncas/alerts/TA14-268A, web site last accessed December 10, 2015.
• cNVD, https://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2014-6271, web site last accessed December 10, 2015.
• dCVSS Calculator, https://www.first.org/cvss/calculator/3.0#CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H, web site last accessed December 10, 2015.
• eCWE-119: Improper Restriction of Operations within the Bounds of a Memory Buffer, http://cwe.mitre.org/data/definitions/119.html, web site last accessed December 10, 2015.
• fUS-CERT Alert (TA14-098A) - OpenSSL ‘Heartbleed’ vulnerability, https://www.us-cert.gov/ncas/alerts/TA14-098A, web site last accessed December 10, 2015.
• gNVD, https://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2014-0160, web site last accessed December 10, 2015.
• hCVSS Calculator, https://www.first.org/cvss/calculator/3.0#CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N, web site last accessed December 10, 2015.
• iCWE-119: Improper Restriction of Operations within the Bounds of a Memory Buffer, http://cwe.mitre.org/data/definitions/119.html, web site last accessed December 10, 2015.
• jNVD, https://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2012-2152, web site last accessed December 10, 2015.
• kCVSS Calculator, https://www.first.org/cvss/calculator/3.0#CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L, web site last accessed December 10, 2015.
• lCWE-592: Authentication Bypass Issues, http://cwe.mitre.org/data/definitions/592.html, web site last accessed January 05, 2016.
• mNVD, https://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2015-7938, NIST uses this advisory to create the CVE web site report. This web site will be active sometime after publication of this advisory.
• nCVSS Calculator, https://www.first.org/cvss/calculator/3.0#CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H, web site last accessed January 05, 2016.

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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