Siemens ST7 ScadaConnect

As of January 10, 2023, CISA will no longer be updating ICS security advisories for Siemens product vulnerabilities beyond the initial advisory. For the most up-to-date information on vulnerabilities in this advisory, please see Siemens’ ProductCERT Security Advisories (CERT Services | Services | Siemens Global).

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1. EXECUTIVE SUMMARY

• CVSS v3 8.2 *ATTENTION: Exploitable remotely/low attack complexity
• Vendor: Siemens
• Equipment: ST7 ScadaConnect
• Vulnerabilities: Integer Overflow or Wraparound, Double Free, Improper Certificate Validation, Inefficient Regular Expression Complexity, Improper Check for Unusual or Exceptional Conditions, Improper Input Validation, NULL Pointer Dereference, Missing Encryption of Sensitive Data, Improper Restriction of Operations within the Bounds of a Memory Buffer, Uncontrolled Resource Consumption

2. RISK EVALUATION

Successful exploitation of these vulnerabilities could allow an attacker to disclose information, cause a denial-of-service (DoS) condition, or execute arbitrary code.

3. TECHNICAL DETAILS

3.1 AFFECTED PRODUCTS

The following Siemens products, are affected:

• Siemens ST7 ScadaConnect (6NH7997-5DA10-0AA0): Versions prior to 1.1

3.2 Vulnerability Overview

3.2.1INTEGER OVERFLOW OR WRAPAROUND CWE-190

An issue was discovered in libxml2 before 2.10.3. When parsing a multi-gigabyte XML document with the XML_PARSE_HUGE parser option enabled, several integer counters can overflow. This results in an attempt to access an array at a negative 2GB offset, typically leading to a segmentation fault.

CVE-2022-40303 has been assigned to this vulnerability. A CVSS v3 base score of 7.5 has been assigned; the CVSS vector string is (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H).

3.2.2DOUBLE FREE CWE-415

An issue was discovered in libxml2 before 2.10.3. Certain invalid XML entity definitions can corrupt a hash table key, potentially leading to subsequent logic errors. In one case, a double-free can be provoked.

CVE-2022-40304 has been assigned to this vulnerability. A CVSS v3 base score of 7.8 has been assigned; the CVSS vector string is (CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H).

3.2.3IMPROPER CERTIFICATE VALIDATION CWE-295

A security vulnerability has been identified in all supported versions of OpenSSL related to the verification of X.509 certificate chains that include policy constraints. Attackers may be able to exploit this vulnerability by creating a malicious certificate chain that triggers exponential use of computational resources, leading to a denial-of-service (DoS) attack on affected systems. Policy processing is disabled by default but can be enabled by passing the -policy argument to the command line utilities or by calling the X509_VERIFY_PARAM_set1_policies() function.

CVE-2023-0464 has been assigned to this vulnerability. A CVSS v3 base score of 7.5 has been assigned; the CVSS vector string is (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H).

3.2.4IMPROPER CERTIFICATE VALIDATION CWE-295

Applications that use a non-default option when verifying certificates may be vulnerable to an attack from a malicious CA to circumvent certain checks. Invalid certificate policies in leaf certificates are silently ignored by OpenSSL and other certificate policy checks are skipped for that certificate. A malicious CA could use this to deliberately assert invalid certificate policies in order to circumvent policy checking on the certificate altogether. Policy processing is disabled by default but can be enabled by passing the -policy argument to the command line utilities or by calling the X509_VERIFY_PARAM_set1_policies() function.

CVE-2023-0465 has been assigned to this vulnerability. A CVSS v3 base score of 5.3 has been assigned; the CVSS vector string is (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N).

3.2.5IMPROPER CERTIFICATE VALIDATION CWE-295

The function X509_VERIFY_PARAM_add0_policy() is documented to implicitly enable the certificate policy check when doing certificate verification. However the implementation of the function does not enable the check which allows certificates with invalid or incorrect policies to pass the certificate verification.As suddenly enabling the policy check could break existing deployments it was decided to keep the existing behavior of the X509_VERIFY_PARAM_add0_policy()function.Instead the applications that require OpenSSL to perform certificate policy check need to use X509_VERIFY_PARAM_set1_policies() or explicitly enable the policy check by calling X509_VERIFY_PARAM_set_flags() with the X509_V_FLAG_POLICY_CHECK flag argument.Certificate policy checks are disabled by default in OpenSSL and are not commonly used by applications.

CVE-2023-0466 has been assigned to this vulnerability. A CVSS v3 base score of 5.3 has been assigned; the CVSS vector string is (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N).

3.2.6INEFFICIENT REGULAR EXPRESSION COMPLEXITY CWE-1333

Issue summary: Checking excessively long DH keys or parameters may be very slow. Impact summary: Applications that use the functions DH_check(), DH_check_ex() or EVP_PKEY_param_check() to check a DH key or DH parameters may experience long delays. Where the key or parameters that are being checked have been obtained from an untrusted source this may lead to a Denial-of-Service. The function DH_check() performs various checks on DH parameters. One of those checks confirms that the modulus (‘p’ parameter) is not too large. Trying to use a very large modulus is slow and OpenSSL will not normally use a modulus which is over 10,000 bits in length. However the DH_check() function checks numerous aspects of the key or parameters that have been supplied. Some of those checks use the supplied modulus value even if it has already been found to be too large. An application that calls DH_check() and supplies a key or parameters obtained from an untrusted source could be vulnerable to a Denial-of-Service attack. The function DH_check() is itself called by a number of other OpenSSL functions. An application calling any of those other functions may similarly be affected. The other functions affected by this are DH_check_ex() and EVP_PKEY_param_check(). Also vulnerable are the OpenSSL dhparam and pkeyparam command line applications when using the ‘-check’ option. The OpenSSL SSL/TLS implementation is not affected by this issue. The OpenSSL 3.0 and 3.1 FIPS providers are not affected by this issue.

CVE-2023-3446 has been assigned to this vulnerability. A CVSS v3 base score of 5.3 has been assigned; the CVSS vector string is (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L).

3.2.7IMPROPER CHECK FOR UNUSUAL OR EXCEPTIONAL CONDITIONS CWE-754

Issue summary: Generating excessively long X9.42 DH keys or checking excessively long X9.42 DH keys or parameters may be very slow. Impact summary: Applications that use the functions DH_generate_key() to generate an X9.42 DH key may experience long delays. Likewise, applications that use DH_check_pub_key(), DH_check_pub_key_ex() or EVP_PKEY_public_check() to check an X9.42 DH key or X9.42 DH parameters may experience long delays. Where the key or parameters that are being checked have been obtained from an untrusted source this may lead to a Denial-of-Service. While DH_check() performs all the necessary checks (as of CVE-2023-3817), DH_check_pub_key() doesn’t make any of these checks, and is therefore vulnerable for excessively large P and Q parameters. Likewise, while DH_generate_key() performs a check for an excessively large P, it doesn’t check for an excessively large Q. An application that calls DH_generate_key() or DH_check_pub_key() and supplies a key or parameters obtained from an untrusted source could be vulnerable to a Denial-of-Service attack. DH_generate_key() and DH_check_pub_key() are also called by a number of other OpenSSL functions. An application calling any of those other functions may similarly be affected. The other functions affected by this are DH_check_pub_key_ex(), EVP_PKEY_public_check(), and EVP_PKEY_generate(). Also vulnerable are the OpenSSL pkey command line application when using the “-pubcheck” option, as well as the OpenSSL genpkey command line application. The OpenSSL SSL/TLS implementation is not affected by this issue. The OpenSSL 3.0 and 3.1 FIPS providers are not affected by this issue.

CVE-2023-5678 has been assigned to this vulnerability. A CVSS v3 base score of 5.3 has been assigned; the CVSS vector string is (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L).

3.2.8IMPROPER INPUT VALIDATION CWE-20

.NET and Visual Studio Remote Code Execution Vulnerability

CVE-2023-21808 has been assigned to this vulnerability. A CVSS v3 base score of 7.8 has been assigned; the CVSS vector string is (CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H).

3.2.9IMPROPER INPUT VALIDATION CWE-20

.NET, .NET Framework, and Visual Studio Remote Code Execution Vulnerability

CVE-2023-24895 has been assigned to this vulnerability. A CVSS v3 base score of 7.8 has been assigned; the CVSS vector string is (CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H).

3.2.10IMPROPER INPUT VALIDATION CWE-20

.NET, .NET Framework, and Visual Studio Remote Code Execution Vulnerability

CVE-2023-24897 has been assigned to this vulnerability. A CVSS v3 base score of 7.8 has been assigned; the CVSS vector string is (CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H).

3.2.11IMPROPER INPUT VALIDATION CWE-20

.NET, .NET Framework, and Visual Studio Elevation of Privilege Vulnerability

CVE-2023-24936 has been assigned to this vulnerability. A CVSS v3 base score of 7.5 has been assigned; the CVSS vector string is (CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H).

3.2.12IMPROPER INPUT VALIDATION CWE-20

.NET DLL Hijacking Remote Code Execution Vulnerability

CVE-2023-28260 has been assigned to this vulnerability. A CVSS v3 base score of 7.8 has been assigned; the CVSS vector string is (CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H).

3.2.13NULL POINTER DEREFERENCE CWE-476

In libxml2 before 2.10.4, parsing of certain invalid XSD schemas can lead to a NULL pointer dereference and subsequently a segfault. This occurs in xmlSchemaFixupComplexType in xmlschemas.c.

CVE-2023-28484 has been assigned to this vulnerability. A CVSS v3 base score of 6.5 has been assigned; the CVSS vector string is (CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H).

3.2.14IMPROPER INPUT VALIDATION CWE-20

.NET, .NET Framework, and Visual Studio Denial-of-Service Vulnerability

CVE-2023-29331 has been assigned to this vulnerability. A CVSS v3 base score of 7.5 has been assigned; the CVSS vector string is (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H).

3.2.15DOUBLE FREE CWE-415

An issue was discovered in libxml2 before 2.10.4. When hashing empty dict strings in a crafted XML document, xmlDictComputeFastKey in dict.c can produce non-deterministic values, leading to various logic and memory errors, such as a double free. This behavior occurs because there is an attempt to use the first byte of an empty string, and any value is possible (not solely the ‘\0’ value).

CVE-2023-29469 has been assigned to this vulnerability. A CVSS v3 base score of 6.5 has been assigned; the CVSS vector string is (CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H).

3.2.16IMPROPER INPUT VALIDATION CWE-20

.NET and Visual Studio Elevation of Privilege Vulnerability

CVE-2023-32032 has been assigned to this vulnerability. A CVSS v3 base score of 6.5 has been assigned; the CVSS vector string is (CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:L/I:H/A:H).

3.2.17IMPROPER INPUT VALIDATION CWE-20

.NET and Visual Studio Remote Code Execution Vulnerability

CVE-2023-33126 has been assigned to this vulnerability. A CVSS v3 base score of 7.3 has been assigned; the CVSS vector string is (CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:H).

3.2.18IMPROPER INPUT VALIDATION CWE-20

.NET and Visual Studio Elevation of Privilege Vulnerability

CVE-2023-33127 has been assigned to this vulnerability. A CVSS v3 base score of 8.1 has been assigned; the CVSS vector string is (CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H).

3.2.19IMPROPER INPUT VALIDATION CWE-20

.NET and Visual Studio Remote Code Execution Vulnerability

CVE-2023-33128 has been assigned to this vulnerability. A CVSS v3 base score of 7.3 has been assigned; the CVSS vector string is (CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:H).

3.2.20IMPROPER INPUT VALIDATION CWE-20

.NET and Visual Studio Elevation of Privilege Vulnerability

CVE-2023-33135 has been assigned to this vulnerability. A CVSS v3 base score of 7.3 has been assigned; the CVSS vector string is (CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:H).

3.2.21IMPROPER INPUT VALIDATION CWE-20

ASP.NET and Visual Studio Security Feature Bypass Vulnerability

CVE-2023-33170 has been assigned to this vulnerability. A CVSS v3 base score of 8.1 has been assigned; the CVSS vector string is (CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H).

3.2.22IMPROPER INPUT VALIDATION CWE-20

.NET and Visual Studio Remote Code Execution Vulnerability

CVE-2023-35390 has been assigned to this vulnerability. A CVSS v3 base score of 7.8 has been assigned; the CVSS vector string is (CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H).

3.2.23IMPROPER INPUT VALIDATION CWE-20

ASP.NET Core SignalR and Visual Studio Information Disclosure Vulnerability

CVE-2023-35391 has been assigned to this vulnerability. A CVSS v3 base score of 6.2 has been assigned; the CVSS vector string is (CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N).

3.2.24IMPROPER INPUT VALIDATION CWE-20

ASP.NET Core Denial-of-Service Vulnerability

CVE-2023-36038 has been assigned to this vulnerability. A CVSS v3 base score of 8.2 has been assigned; the CVSS vector string is (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:H).

3.2.25IMPROPER INPUT VALIDATION CWE-20

.NET, .NET Framework, and Visual Studio Elevation of Privilege Vulnerability

CVE-2023-36049 has been assigned to this vulnerability. A CVSS v3 base score of 7.6 has been assigned; the CVSS vector string is (CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:H/A:L).

3.2.26IMPROPER INPUT VALIDATION CWE-20

Microsoft QUIC Denial-of-Service Vulnerability

CVE-2023-36435 has been assigned to this vulnerability. A CVSS v3 base score of 7.5 has been assigned; the CVSS vector string is (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H).

3.2.27IMPROPER INPUT VALIDATION CWE-20

ASP.NET Core - Security Feature Bypass Vulnerability

CVE-2023-36558 has been assigned to this vulnerability. A CVSS v3 base score of 6.2 has been assigned; the CVSS vector string is (CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N).

3.2.28MISSING ENCRYPTION OF SENSITIVE DATA CWE-311

Visual Studio Remote Code Execution Vulnerability

CVE-2023-36792 has been assigned to this vulnerability. A CVSS v3 base score of 7.8 has been assigned; the CVSS vector string is (CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H).

3.2.29MISSING ENCRYPTION OF SENSITIVE DATA CWE-311

Visual Studio Remote Code Execution Vulnerability

CVE-2023-36793 has been assigned to this vulnerability. A CVSS v3 base score of 7.8 has been assigned; the CVSS vector string is (CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H).

3.2.30MISSING ENCRYPTION OF SENSITIVE DATA CWE-311

Visual Studio Remote Code Execution Vulnerability

CVE-2023-36794 has been assigned to this vulnerability. A CVSS v3 base score of 7.8 has been assigned; the CVSS vector string is (CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H).

3.2.31MISSING ENCRYPTION OF SENSITIVE DATA CWE-311

Visual Studio Remote Code Execution Vulnerability

CVE-2023-36796 has been assigned to this vulnerability. A CVSS v3 base score of 7.8 has been assigned; the CVSS vector string is (CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H).

3.2.32IMPROPER INPUT VALIDATION CWE-20

.NET Core and Visual Studio Denial-of-Service Vulnerability

CVE-2023-36799 has been assigned to this vulnerability. A CVSS v3 base score of 6.5 has been assigned; the CVSS vector string is (CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H).

3.2.33IMPROPER INPUT VALIDATION CWE-20

Microsoft QUIC Denial-of-Service Vulnerability

CVE-2023-38171 has been assigned to this vulnerability. A CVSS v3 base score of 7.5 has been assigned; the CVSS vector string is (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H).

3.2.34IMPROPER INPUT VALIDATION CWE-20

.NET Core and Visual Studio Denial-of-Service Vulnerability

CVE-2023-38178 has been assigned to this vulnerability. A CVSS v3 base score of 7.5 has been assigned; the CVSS vector string is (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H).

3.2.35IMPROPER INPUT VALIDATION CWE-20

.NET and Visual Studio Denial-of-Service Vulnerability

CVE-2023-38180 has been assigned to this vulnerability. A CVSS v3 base score of 7.5 has been assigned; the CVSS vector string is (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H).

3.2.36IMPROPER RESTRICTION OF OPERATIONS WITHIN THE BOUNDS OF A MEMORY BUFFER CWE-119

Xmlsoft Libxml2 v2.11.0 was discovered to contain an out-of-bounds read via the xmlSAX2StartElement() function at /libxml2/SAX2.c. This vulnerability allows attackers to cause a Denial-of-Service (DoS) via supplying a crafted XML file. NOTE: the vendor’s position is that the product does not support the legacy SAX1 interface with custom callbacks; there is a crash even without crafted input.

CVE-2023-39615 has been assigned to this vulnerability. A CVSS v3 base score of 6.5 has been assigned; the CVSS vector string is (CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H).

3.2.37UNCONTROLLED RESOURCE CONSUMPTION CWE-400

The HTTP/2 protocol allows a denial-of-service (server resource consumption) because request cancellation can reset many streams quickly, as exploited in the wild in August through October 2023.

CVE-2023-44487 has been assigned to this vulnerability. A CVSS v3 base score of 7.5 has been assigned; the CVSS vector string is (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H).

3.3 BACKGROUND

• CRITICAL INFRASTRUCTURE SECTORS: Commercial Facilities, Energy, Critical Manufacturing
• COUNTRIES/AREAS DEPLOYED: Worldwide
• COMPANY HEADQUARTERS LOCATION: Germany

3.4 RESEARCHER

Siemens reported these vulnerabilities to CISA.

4. MITIGATIONS

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

• ST7 ScadaConnect (6NH7997-5DA10-0AA0): Update to V1.1 or later version.

As a general security measure, Siemens recommends protecting network access to devices with appropriate mechanisms. To operate the devices in a protected IT environment, Siemens recommends configuring the environment according to Siemens’ operational guidelines for industrial security and following recommendations in the product manuals.

Additional information on industrial security by Siemens can be found on the Siemens industrial security webpage

For more information see the associated Siemens security advisory SSA-341067 in HTML and CSAF.

CISA recommends users take defensive measures to minimize the risk of exploitation of these vulnerabilities, such as:

• Minimize network exposure for all control system devices and/or systems, ensuring they are not accessible from the internet.
• Locate control system networks and remote devices behind firewalls and isolating them from business networks.
• When remote access is required, use more secure methods, such as Virtual Private Networks (VPNs). Recognize VPNs may have vulnerabilities, should be updated to the most recent version available, and are only as secure as the connected devices.

CISA reminds organizations to perform proper impact analysis and risk assessment prior to deploying defensive measures.

CISA also provides a section for control systems security recommended practices on the ICS webpage on cisa.gov. Several CISA products detailing cyber defense best practices are available for reading and download, including Improving Industrial Control Systems Cybersecurity with Defense-in-Depth Strategies.

CISA encourages organizations to implement recommended cybersecurity strategies for proactive defense of ICS assets.

Additional mitigation guidance and recommended practices are publicly available on the ICS webpage at cisa.gov in the technical information paper, ICS-TIP-12-146-01B–Targeted Cyber Intrusion Detection and Mitigation Strategies.

Organizations observing suspected malicious activity should follow established internal procedures and report findings to CISA for tracking and correlation against other incidents.

CISA also recommends users take the following measures to protect themselves from social engineering attacks:

• Do not click web links or open attachments in unsolicited email messages.
• Refer to Recognizing and Avoiding Email Scams for more information on avoiding email scams.
• Refer to Avoiding Social Engineering and Phishing Attacks for more information on social engineering attacks.

No known public exploitation specifically targeting these vulnerabilities has been reported to CISA at this time.

5. UPDATE HISTORY

• June 13, 2024: Initial Publication