Siemens SCALANCE X-200IRT Switch Family User Impersonation Vulnerability

OVERVIEW

Siemens has identified a user impersonation vulnerability in its SCALANCE X-200IRT Switch Family. Siemens has produced a firmware update that mitigates this vulnerability.

This vulnerability could be exploited remotely.

AFFECTED PRODUCTS

Siemens reports that the vulnerability affects the following products:

• SCALANCE X-200IRT switch family; All versions prior to V5.2.0

IMPACT

This vulnerability could allow an attacker to impersonate legitimate users of the web interface.

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

BACKGROUND

Siemens is a multinational company headquartered in Munich, Germany.

SCALANCE-X switches are used to connect industrial components like PLCs or HMIs. The switches offer a web interface to enable users to change the configuration using a common web browser, as well as an FTP server to download and upload configuration and firmware files. According to Siemens, these devices are deployed across most sectors including Chemical, Communications, Critical Manufacturing, Dams, Defense Industrial Base, Energy, Food and Agriculture, Government Facilities, Transportation Systems, and Water and Wastewater Systems. Siemens estimates that these products are used worldwide.

VULNERABILITY CHARACTERIZATION

VULNERABILIY OVERVIEW

IMPROPER AUTHENTICATIONCWE-287: Improper Authentication, http://cwe.mitre.org/data/definitions/287.html, web site last accessed February 03, 2015.

The device’s web server could allow unauthenticated attackers to impersonate legitimate users of the web interface (Port 80/TCP and Port 443/TCP) if an active web session of an authenticated user exists at the time of attack.

CVE- 2015-1049NVD, http://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2015-1049, 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 v2 base score of 6.8 has been assigned; the CVSS vector string is (AV:N/AC:M/Au:N/C:P/I:P/A:P).CVSS Calculator, http://nvd.nist.gov/cvss.cfm?version=2&vector=AV:N/AC:M/Au:N/C:P/I:P/A:P, web site last accessed February 03, 2015.

VULNERABILITY DETAILS

EXPLOITABILITY

This vulnerability could be exploited remotely.

EXISTENCE OF EXPLOIT

No known public exploits specifically target this vulnerability.

DIFFICULTY

An attacker with a medium skill would be able to exploit this vulnerability.

MITIGATION

Siemens provides firmware update V 5.2.0, which fixes the vulnerabilities, and recommends updating as soon as possible. The firmware update is available at:

<http://support.automation.siemens.com/WW/view/en/108892137&gt;

Siemens strongly recommends protecting network access to the web interface of SCALANCE X‑200IRT switches by appropriate mechanisms. It is advised to follow recommended security practices and to configure the environment according to operational guidelines in order to run the devices in a protected IT environment. Siemens operational guidelines are available at:

<http://www.industry.siemens.com/topics/global/en/industrial-security/Documents/operational_guidelines_industrial_security_en.pdf&gt;

For more information on these vulnerabilities and detailed instructions, please see Siemens Security Advisory SSA-954136 at the following location:

<http://www.siemens.com/cert/advisories&gt;

ICS-CERT encourages asset owners to take additional defensive measures to protect against this and other cybersecurity risks.

• 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 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. ICS-CERT reminds organizations to perform proper impact analysis and risk assessment prior to deploying defensive measures.

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.