This updated advisory is a follow-up to the original advisory titled ICSA-22-195-12 Siemens SRCS VPN Feature in SIMATIC CP Devices that was published July 14, 2022, on the ICS webpage on cisa.gov/ics.
These vulnerabilities, if successfully exploited when authorized personnel are using the SINEMA Remote Connect Server (SRCS) VPN feature, could allow an attacker to execute arbitrary code with elevated privileges under certain circumstances.
The following versions of SIMATIC CP Devices, communication processors, are affected:
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The application lacks proper validation of user-supplied data when parsing specific messages. This could result in a heap-based buffer overflow. An attacker could leverage this vulnerability to execute arbitrary code in the context of the device.
CVE-2022-34819 has been assigned to this vulnerability. A CVSS v3 base score of 10.0 has been assigned; the CVSS vector string is (AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H).
The application does not correctly escape some user provided fields during the authentication process. This could allow an attacker to inject custom commands and execute arbitrary code with elevated privileges.
CVE-2022-34820 has been assigned to this vulnerability. A CVSS v3 base score of 8.4 has been assigned; the CVSS vector string is (AV:A/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H).
By injecting code to specific configuration options for OpenVPN, an attacker could execute arbitrary code with elevated privileges.
CVE-2022-34821 has been assigned to this vulnerability. A CVSS v3 base score of 7.6 has been assigned; the CVSS vector string is (AV:A/AC:H/PR:H/UI:N/S:C/C:H/I:H/A:H).
Siemens reported these vulnerabilities to CISA.
Siemens recommends updating to the latest version of its software if available:
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Siemens has identified the following specific workarounds and mitigations that customers can implement to reduce exploitation risk:
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 Siemensβ 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 Siemens Security Advisory SSA-517377.
CISA recommends users take defensive measures to minimize the risk of exploitation of this vulnerability these vulnerabilities. Specifically, users should:
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 at cisa.gov/ics. 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.
Additional mitigation guidance and recommended practices are publicly available on the ICS webpage at cisa.gov/ics in the technical information paper, ICS-TIP-12-146-01BβTargeted 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:
No known public exploits specifically target these vulnerabilities.
web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2022-34819
web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2022-34820
web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2022-34821
cert-portal.siemens.com/productcert/pdf/ssa-517377.pdf
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