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Advisory (ICSA-13-338-01)

Siemens SINAMICS S/G Authentication Bypass Vulnerability

Original release date: December 04, 2013 | Last revised: December 17, 2013

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OVERVIEW

Siemens has identified an authentication bypass vulnerability in the SINAMICS S/G product family. Siemens has produced a firmware update that mitigates this vulnerability and has tested the update to validate that it resolves the vulnerability. Exploitation of this vulnerability could allow an attacker to access administrative functions on the device without authentication.

This vulnerability could be exploited remotely.

AFFECTED PRODUCTS

Siemens reports that the vulnerability affects the following versions:

  • SINAMICS S/G family with firmware version prior to 4.6.11.

IMPACT

Successful exploitation of this vulnerability may allow attackers to perform administrative operations over the network without authentication.

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 an international company headquartered in Munich, Germany. Siemens develops products mainly in the energy, transportation, and healthcare sectors.

The affected product, SINAMICS S/G family, is used to control a variety of drives, especially in mechanical engineering and plant construction. In addition, SINAMICS S/G family interacts with motion controllers that are used to coordinate synchronous operations or complex technology functions.

VULNERABILITY CHARACTERIZATION

VULNERABILITY OVERVIEW

AUTHENTICATION BYPASSa

The SINAMICS S/G open ports and services, FTP 21/TCP and Telnet 23/TCP, might allow attackers to perform administrative operations over the network without authentication.

CVE-2013-6920b has been assigned to this vulnerability. A CVSS v2 base score of 10.0 has been assigned; the CVSS vector string is (AV:N/AC:L/Au:N/C:C/I:C/A:C).c

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 low skill would be able to exploit this vulnerability. 

MITIGATION

Siemens has produced a firmware update, SINAMICS S/G V4.6.11 and 4.7, which resolves this vulnerability. Asset owners and operators should contact Siemens customer support to acquire the update.

The firmware update can be obtained from your local Siemens account manager.

Siemens security advisory is located here:

http://www.siemens.com/innovation/pool/de/forschungsfelder/siemens_security_advisory_ssa-742938.pdf

NCCIC/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 VPN is only as secure as the connected devices.

NCCIC/ICS-CERT also provides a section for control systems security recommended practices on the NCCIC/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. NCCIC/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 NCCIC/ICS-CERT Technical Information Paper, ICS-TIP-12-146-01B—Targeted Cyber Intrusion Mitigation Strategies,d that is available for download from the NCCIC/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 NCCIC/ICS-CERT for tracking and correlation against other incidents.


Contact Information

For any questions related to this report, please contact ICS-CERT at:

Email: ics-cert@hq.dhs.gov
Toll Free: 1-877-776-7585
International Callers: (208) 526-0900

For industrial control systems security information and incident reporting: http://ics-cert.us-cert.gov

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