Siemens SINAMICS S/G Authentication Bypass Vulnerability


时间: 2013-12-04

风险等级: 未知

ICSA: ICS Advisory (ICSA-13-338-01)

厂商: 未知



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.


Siemens reports that the vulnerability affects the following versions:

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


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.


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.




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



This vulnerability could be exploited remotely.


No known public exploits specifically target this vulnerability.


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


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:

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: 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 (

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.

  • a. CWE-592: Authentication Bypass Issues,, Web site last accessed December 04, 2013.
  • b. NVD,, NIST uses this advisory to create the CVE Web site report. This Web site will be active sometime after publication of this advisory.
  • c. CVSS Calculator,, Web site last accessed December 04, 2013.
  • d. Targeted Cyber Intrusion Detection and Mitigation Strategies,, Web site last accessed December 04, 2013.