SSA-625789

Siemens Security Advisory by Siemens ProductCERT

SSA-625789: Multiple Vulnerabilities in SIMATIC S7-1200 CPU V1/V2 Devices

Publication Date:	2011-06-10
Last Update:	2025-10-14
Current Version:	V1.4
CVSS v3.1 Base Score:	7.5
CVSS v4.0 Base Score:	8.7

SUMMARY

SIMATIC S7-1200 CPU V1/V2 controllers contain two vulnerabilities that could allow an unauthenticated remote attacker

to trigger functions by record and playback of legitimate network communication, or
to place the controller in stop/defect state by causing a communications error.

Siemens has released new versions for the affected products and recommends to update to the latest versions.

KNOWN AFFECTED PRODUCTS

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Affected Product and Versions	Remediation
SIMATIC S7-1200 CPU V1 family (incl. SIPLUS variants)	Show more details
SIMATIC S7-1200 CPU V1 family (incl. SIPLUS variants) All versions < V2.0.3 affected by CVE-2011-20001	Update to V2.0.3 or later version See further recommendations from section Workarounds and Mitigations
SIMATIC S7-1200 CPU V1 family (incl. SIPLUS variants) All versions < V2.0.2 affected by CVE-2011-20002	Update to V2.0.2 or later version See further recommendations from section Workarounds and Mitigations
SIMATIC S7-1200 CPU V2 family (incl. SIPLUS variants)	Show more details
SIMATIC S7-1200 CPU V2 family (incl. SIPLUS variants) All versions < V2.0.3 affected by CVE-2011-20001	Update to V2.0.3 or later version See further recommendations from section Workarounds and Mitigations
SIMATIC S7-1200 CPU V2 family (incl. SIPLUS variants) All versions < V2.0.2 affected by CVE-2011-20002	Update to V2.0.2 or later version See further recommendations from section Workarounds and Mitigations

WORKAROUNDS AND MITIGATIONS

Siemens has identified the following specific workarounds and mitigations that customers can apply to reduce the risk:

CVE-2011-20001: Disable the web server if possible

Product-specific remediations or mitigations can be found in the section Known Affected Products.
Please follow the General Security Recommendations.

GENERAL SECURITY RECOMMENDATIONS

As a general security measure, Siemens strongly recommends to protect network access to devices with appropriate mechanisms. In order to operate the devices in a protected IT environment, Siemens recommends to configure the environment according to Siemens' operational guidelines for Industrial Security (Download: https://www.siemens.com/cert/operational-guidelines-industrial-security), and to follow the recommendations in the product manuals. Additional information on Industrial Security by Siemens can be found at: https://www.siemens.com/industrialsecurity

PRODUCT DESCRIPTION

SIMATIC S7-1200 CPU products have been designed for discrete and continuous control in industrial environments such as manufacturing, food and beverages, and chemical industries worldwide.

SIPLUS extreme products are designed for reliable operation under extreme conditions and are based on SIMATIC, LOGO!, SITOP, SINAMICS, SIMOTION, SCALANCE or other devices. SIPLUS devices use the same firmware as the product they are based on.

VULNERABILITY DESCRIPTION

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This chapter describes all vulnerabilities (CVE-IDs) addressed in this security advisory. Wherever applicable, it also documents the product-specific impact of the individual vulnerabilities.

Vulnerability CVE-2011-20001

The web server interface of affected devices improperly processes incoming malformed HTTP traffic at high rate. This could allow an unauthenticated remote attacker to force the device entering the stop/defect state, thus creating a denial of service condition.

CVSS v3.1 Base Score	7.5
CVSS v3.1 Vector	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CVSS v4.0 Base Score	8.7
CVSS v4.0 Vector	CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
CWE	CWE-20: Improper Input Validation

Vulnerability CVE-2011-20002

Affected controllers are vulnerable to capture-replay in the communication with the engineering software. This could allow an on-path attacker between the engineering software and the controller to execute any previously recorded commands at a later time (e.g. set the controller to STOP), regardless whether or not the controller had a password configured.

CVSS v3.1 Base Score	7.4
CVSS v3.1 Vector	CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:H
CVSS v4.0 Base Score	8.3
CVSS v4.0 Vector	CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:H/VA:H/SC:N/SI:N/SA:N
CWE	CWE-294: Authentication Bypass by Capture-replay

ACKNOWLEDGMENTS

Siemens thanks the following parties for their efforts:

Artem Zinenko from Kaspersky for pointing out that SIPLUS should also be mentioned
Industrial Control System Cyber Emergency Response Team (ICS-CERT) for coordination efforts
Dillon Beresford from NSS Labs for reporting the vulnerabilities

ADDITIONAL INFORMATION

For further inquiries on security vulnerabilities in Siemens products and solutions, please contact the Siemens ProductCERT: https://www.siemens.com/cert/advisories

HISTORY DATA

V1.0 (2011-06-10):	Publication Date
V1.1 (2011-07-05):	Modification of CVSS scoring, solution and version information
V1.2 (2011-09-12):	Update of solution section by removing mentioning of air gap
V1.3 (2020-02-10):	SIPLUS devices now explicitly mentioned in the list of affected products
V1.4 (2025-10-14):	Assigned CVE IDs (CVE-2011-20001/-20002) instead of the deprecated SVE IDs (SVE-2011-0001/-0002); Corrected CVSS vector of CVE-2011-20002; Updated SSA to current data model and support of csaf

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