SSA-974843

Siemens Security Advisory by Siemens ProductCERT

SSA-974843: Denial-of-Service Vulnerability in SIPROTEC 4 and SIPROTEC Compact Relay Families

Publication Date:	2020-02-11
Last Update:	2020-02-11
Current Version:	V1.0
CVSS v3.1 Base Score:	7.5

SUMMARY

The SIPROTEC 4 and SIPROTEC Compact devices are affected by a security vulnerability which could allow an attacker to conduct a Denial-of-Service attack over the network when equipped with EN100 Ethernet communication modules. Siemens recommends specific countermeasures to mitigate the issue.

AFFECTED PRODUCTS AND SOLUTION

Affected Product and Versions	Remediation
SIPROTEC 4 and SIPROTEC Compact relays equipped with EN100 Ethernet communication modules: All versions	See recommendations from Section Workaround and Mitigations

WORKAROUNDS AND MITIGATIONS

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

For relays equipped with EN100 Ethernet communication modules having IEC 61850 firmware version V4.30 and higher, activate DTLS-secured communication in DIGSI 4 and in the EN100 module, and set a connection password in the EN100 module to permit only authenticated users to access the relay over the network.
Limit access to port 50000/UDP.

GENERAL SECURITY RECOMMENDATIONS

Operators of critical power systems (e.g. TSOs) worldwide are usually required by regulations to build resilience into the power grids by applying multi-level redundant secondary protection schemes. It is therefore recommended that the operators check whether appropriate resilient protection measures are in place. The risk of cyber incidents impacting the grid's reliability can thus be minimized by virtue of the grid design.

Siemens strongly recommends applying the provided security updates using the corresponding tooling and documented procedures made available with the product. If supported by the product, an automated means to apply the security updates across multiple product instances may be used. Siemens strongly recommends prior validation of any security update before being applied, and supervision by trained staff of the update process in the target environment.

As a general security measure Siemens strongly recommends to protect network access with appropriate mechanisms (e.g. firewalls, segmentation, VPN). It is advised to configure the environment according to our operational guidelines in order to run the devices in a protected IT environment.

Recommended security guidelines to Secure Substations can be found at:

https://www.siemens.com/gridsecurity

PRODUCT DESCRIPTION

SIPROTEC 4 and SIPROTEC Compact devices provide a wide range of integrated protection, control, measurement, and automation functions for electrical substations and other fields of application.

VULNERABILITY CLASSIFICATION

The vulnerability classification has been performed by using the CVSS scoring system in version 3.1 (CVSS v3.1) (https://www.first.org/cvss). The CVSS environmental score is specific to the customer’s environment and will impact the overall CVSS score. The environmental score should therefore be individually defined by the customer to accomplish final scoring.

An additional classification has been performed using the CWE classification, a community-developed list of common software security weaknesses. This serves as a common language and as a baseline for weakness identification, mitigation, and prevention efforts. A detailed list of CWE classes can be found at: https://cwe.mitre.org/.

Vulnerability CVE-2019-19279

Specially crafted packets sent to port 50000/UDP of the EN100 Ethernet communication modules could cause a Denial-of-Service of the affected device. A manual reboot is required to recover the service of the device. At the time of advisory publication no public exploitation of this security vulnerability was known to Siemens.

CVSS v3.1 Base Score	7.5
CVSS Vector	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H/E:P/RL:T/RC:C
CWE:	CWE-20: Improper Input Validation

ACKNOWLEDGMENTS

Siemens thanks the following parties for their efforts:

Tal Keren from Claroty for coordinated disclosure

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 (2020-02-11): Publication Date

Siemens Security Advisories are subject to the terms and conditions contained in Siemens’ underlying license terms or other applicable agreements previously agreed to with Siemens (hereinafter "License Terms"). To the extent applicable to information, software or documentation made available in or through a Siemens Security Advisory, the Terms of Use of Siemens’ Global Website (https://www.siemens.com/terms_of_use, hereinafter "Terms of Use"), in particular Sections 8-10 of the Terms of Use, shall apply additionally. In case of conflicts, the License Terms shall prevail over the Terms of Use.

SSA-974843