Siemens has identified the following specific workarounds and mitigations that customers can apply to reduce the risk:
CVE-2021-31344, CVE-2021-31345, CVE-2021-31346, CVE-2021-31889, CVE-2021-31890: Apply network segmentation and put the ECUs behind properly configured gateways/firewalls
CVE-2021-31881, CVE-2021-31882, CVE-2021-31883: Disable DHCP client functionality, if feature not used, by deselecting the TcpIpIpV4General/TcpIpDhcpClientEnabled Pre-Compile configuration option
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.
Capital VSTAR is an efficient implementation of the AUTOSAR standard. It is a complete solution including tools and a software platform to meet engineers' needs, from creating ECU extract updates to software platform configurations.
Although not based on Nucleus RTOS, VSTAR includes its networking module, Nucleus NET.
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-2021-31344
ICMP echo packets with fake IP options allow sending ICMP echo reply messages to arbitrary hosts on the network. (FSMD-2021-0004)
CWE-843: Access of Resource Using Incompatible Type ('Type Confusion')
Vulnerability CVE-2021-31345
The total length of an UDP payload (set in the IP header) is unchecked. This may lead to various side effects, including Information Leak and Denial-of-Service conditions, depending on a user-defined applications that runs on top of the UDP protocol. (FSMD-2021-0006)
CWE-1284: Improper Validation of Specified Quantity in Input
Vulnerability CVE-2021-31346
The total length of an ICMP payload (set in the IP header) is unchecked. This may lead to various side effects, including Information Leak and Denial-of-Service conditions, depending on the network buffer organization in memory. (FSMD-2021-0007)
CWE-1284: Improper Validation of Specified Quantity in Input
Vulnerability CVE-2021-31881
When processing a DHCP OFFER message, the DHCP client application does not validate the length of the Vendor option(s), leading to Denial-of-Service conditions. (FSMD-2021-0008)
The DHCP client application does not validate the length of the Domain Name Server IP option(s) (0x06) when processing DHCP ACK packets. This may lead to Denial-of-Service conditions. (FSMD-2021-0011)
CWE-119: Improper Restriction of Operations within the Bounds of a Memory Buffer
Vulnerability CVE-2021-31883
When processing a DHCP ACK message, the DHCP client application does not validate the length of the Vendor option(s), leading to Denial-of-Service conditions. (FSMD-2021-0013)
The total length of an TCP payload (set in the IP header) is unchecked. This may lead to various side effects, including Information Leak and Denial-of-Service conditions, depending on the network buffer organization in memory. (FSMD-2021-0017)
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 (2021-12-14):
Publication Date
V1.1 (2022-11-08):
Removed CVE-2021-31884 as Capital VSTAR is not affected
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