PT-2012-48: Insecure storage of HTTPS CA certificate and private key in Siemens SIMATIC S7-1200

(PT-2012-48) Positive Technologies Security Advisory
Insecure storage of HTTPS CA certificate and private key in Siemens SIMATIC S7-1200

Vulnerable product

Siemens SIMATIC S7-1200
Version: 2.x


Severity level

Severity level: High
Impact: Spoofing
Access Vector: Remote  

CVSS v2:
Base Score: 9.3
Vector: (AV:N/AC:M/Au:N/C:C/I:C/A:C)

CVE: CVE-2012-3037

Product description

SIMATIC S7-1200 controllers are new modular miniature controllers. Due to the compact modular design with a high performance at the same time, the SIMATIC S7-1200 is suitable for a wide variety of automation applications. Its range of use extends from the replacement of relays and contactors up to complex automation tasks in networks and within distributed structures.

Vulnerability description

The specialists of the Positive Research center have detected "Spoofing" vulnerability in Siemens SIMATIC S7-1200.

The private key for the CA "SIMATIC CONTROLLER" in the S7-1200 V2.x has been compromised.  This could allow an attacker to perform man-in-the-middle attacks or to deploy malicious but trusted web sites.

How to fix

Siemens strongly recommends the user uninstall the CA keys from the browser’s certificate store. Once this is performed, warning messages will occur when attempting to connect to an S7-1200 PLC. The user can manually confirm the identity of the PLC and its certificate and accept it via the browser. This has to be done once for each S7-1200 PLC on the network.

The compromised key is not shared by the S7-1200 V3.x version of PLCs.

Advisory status

29.08.2012 - Vendor is notified
29.08.2012 - Vendor gets vulnerability details
13.09.2012 - Vendor has issued temporary workarounds
26.09.2012 - Public disclosure


The vulnerability has discovered by Dmitry Sklyarov, Positive Research Center (Positive Technologies Company)


Reports on the vulnerabilities previously discovered by Positive Research:

About Positive Technologies

Positive Technologies is among the key players in the IT security market in Russia.

The principal activities of the company include the development of integrated tools for information security monitoring (MaxPatrol); providing IT security consulting services and technical support; development of the Securitylab leading Russian information security portal.

Among the clients of Positive Technologies, there are more than 40 state enterprises, more than 50 banks and financial organizations, 20 telecommunication companies, more than 40 plant facilities, as well as IT, service and retail companies from Russia, the CIS countries, the Baltic States, China, Ecuador, Germany, Great Britain, Holland, Iran, Israel, Japan, Mexico, the Republic of South Africa, Thailand, Turkey, and the USA.

Positive Technologies is a team of highly skilled developers, advisers and experts with years of vast hands-on experience. The company specialists possess professional titles and certificates; they are the members of various international societies and are actively involved in the IT security field development.