SSA-044112: Multiple Vulnerabilities (NUCLEUS:13) in the TCP/IP Stack of Nucleus RTOS
Publication Date:
2021-11-09
Last Update:
2021-12-14
Current Version:
V1.1
CVSS v3.1 Base Score:
9.8
SUMMARY
The TCP/IP stack and related services (FTP, TFTP) of the networking component (Nucleus NET) in Nucleus Real-Time Operating System (RTOS) contain several vulnerabilities, also known as “NUCLEUS:13” and as documented below.
Siemens has released updates for several affected products and recommends to update to the latest versions. Siemens recommends countermeasures for products where updates are not available.
AFFECTED PRODUCTS AND SOLUTION
Affected Product and Versions
Remediation
Nucleus NET:
All versions
Currently no remediation is planned
Nucleus ReadyStart V3:
All versions < V2017.02.4
Update to V2017.02.4 or later version
https://support.sw.siemens.com/en-US/product/1009925838/
Nucleus ReadyStart V4:
All versions < V4.1.1
only affected by
CVE-2021-31344, CVE-2021-31346, CVE-2021-31885, CVE-2021-31890
Update to V4.1.1 or later version
https://support.sw.siemens.com/en-US/product/1336134128/
Nucleus Source Code:
All versions
Contact customer support to receive patch and update information
WORKAROUNDS AND MITIGATIONS
Siemens has not identified any additional specific workarounds or mitigations.
Please follow the General Security Recommendations .
Product specific mitigations can be found in the section Affected Products and Solution .
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
Nucleus NET module incorporates a wide range of standard-compliant networking and communication protocols, drivers, and utilities to deliver full-featured network support in any embedded device. The networking functionality is fully integrated into the Nucleus RTOS and supports a variety of processors and MCUs.
Nucleus ReadyStart is a platform with integrated software IP, tools, and services ideal for applications where a small footprint, deterministic performance, and small code size are essential.
Nucleus RTOS is a highly scalable micro-kernel based real-time operating system designed for scalability and reliability in systems spanning the range of aerospace, industrial, and medical applications. Since V3, Nucleus RTOS (incl. its modules, e.g. Nucleus NET) is an integral part of the Nucleus ReadyStart platform.
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)
CVSS v3.1 Base Score
5.3
CVSS Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N/E:P/RL:O/RC:C
CWE:
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)
CVSS v3.1 Base Score
7.5
CVSS Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N/E:P/RL:O/RC:C
CWE:
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)
CVSS v3.1 Base Score
8.2
CVSS Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:H/E:P/RL:O/RC:C
CWE:
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)
CVSS v3.1 Base Score
7.1
CVSS Vector
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:H/E:P/RL:O/RC:C
CWE:
CWE-125: Out-of-bounds Read
Vulnerability CVE-2021-31882
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)
CVSS v3.1 Base Score
6.5
CVSS Vector
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H/E:P/RL:O/RC:C
CWE:
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)
CVSS v3.1 Base Score
7.1
CVSS Vector
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:H/E:P/RL:O/RC:C
CWE:
CWE-119: Improper Restriction of Operations within the Bounds of a Memory Buffer
Vulnerability CVE-2021-31884
The DHCP client application assumes that the data supplied with the “Hostname” DHCP option is NULL terminated. In cases when global hostname variable is not defined, this may lead to Out-of-bound reads, writes, and Denial-of-service conditions. (FSMD-2021-0014)
CVSS v3.1 Base Score
8.8
CVSS Vector
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H/E:P/RL:O/RC:C
CWE:
CWE-170: Improper Null Termination
Vulnerability CVE-2021-31885
TFTP server application allows for reading the contents of the TFTP memory buffer via sending malformed TFTP commands. (FSMD-2021-0009)
CVSS v3.1 Base Score
7.5
CVSS Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N/E:P/RL:O/RC:C
CWE:
CWE-805: Buffer Access with Incorrect Length Value
Vulnerability CVE-2021-31886
FTP server does not properly validate the length of the “USER” command, leading to stack-based buffer overflows. This may result in Denial-of-Service conditions and Remote Code Execution. (FSMD-2021-0010)
CVSS v3.1 Base Score
9.8
CVSS Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H/E:P/RL:O/RC:C
CWE:
CWE-170: Improper Null Termination
Vulnerability CVE-2021-31887
FTP server does not properly validate the length of the “PWD/XPWD” command, leading to stack-based buffer overflows. This may result in Denial-of-Service conditions and Remote Code Execution. (FSMD-2021-0016)
CVSS v3.1 Base Score
8.8
CVSS Vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:P/RL:O/RC:C
CWE:
CWE-170: Improper Null Termination
Vulnerability CVE-2021-31888
FTP server does not properly validate the length of the “MKD/XMKD” command, leading to stack-based buffer overflows. This may result in Denial-of-Service conditions and Remote Code Execution. (FSMD-2021-0018)
CVSS v3.1 Base Score
8.8
CVSS Vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:P/RL:O/RC:C
CWE:
CWE-170: Improper Null Termination
Vulnerability CVE-2021-31889
Malformed TCP packets with a corrupted SACK option leads to Information Leaks and Denial-of-Service conditions. (FSMD-2021-0015)
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:O/RC:C
CWE:
CWE-191: Integer Underflow (Wrap or Wraparound)
Vulnerability CVE-2021-31890
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)
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:O/RC:C
CWE:
CWE-240: Improper Handling of Inconsistent Structural Elements
ACKNOWLEDGMENTS
Siemens thanks the following parties for their efforts:
Yuval Halaban, Uriel Malin, and Tal Zohar from
Medigate
for coordinated disclosure
Daniel dos Santos, Amine Amri, and Stanislav Dashevskyi from
Forescout Technologies
for coordinated disclosure
ADDITIONAL INFORMATION
For more details regarding the NUCLEUS:13 vulnerabilities in the Nucleus TCP/IP stack refer to the Forescout Publication “NUCLEUS:13” at https://www.forescout.com/research-labs/nucleus-13
Nucleus ReadyStart V3: Several vulnerabilities were already fixed in versions before V2017.02.4:
V2012.08 and later already fix CVE-2021-31881
V2013.08.1 and later already fix CVE-2021-31886
V2014.12 and later already fix CVE-2021-31345
V2017.02.1 and later already fix CVE-2021-31882, CVE-2021-31883, CVE-2021-31884, CVE-2021-31887, CVE-2021-31888
- V2017.02.3 and later already fix CVE-2021-31889For 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 (2021-11-09): Publication Date
V1.1 (2021-12-14): Moved product CAPITAL VSTAR to a separate advisory (SSA-620288)
TERMS OF USE
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://new.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.