Synopsis
The remote OT asset is affected by a vulnerability.
Description
The Diffie-Hellman Key Agreement Protocol allows remote attackers (from the client side) to send arbitrary numbers that are actually not public keys, and trigger expensive server-side DHE modular- exponentiation calculations, aka a D(HE)ater attack. The client needs very little CPU resources and network bandwidth. The attack may be more disruptive in cases where a client can require a server to select its largest supported key size. The basic attack scenario is that the client must claim that it can only communicate with DHE, and the server must be configured to allow DHE.
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Solution
The following text was originally created by the Cybersecurity and Infrastructure Security Agency (CISA). The original can be found at CISA.gov.
Siemens identified the following specific workarounds and mitigations to reduce risk:
- CVE-2022-37885, CVE-2022-37886, CVE-2022-37887, CVE-2022-37888, and CVE-2022-37889: Enable CPSec via the cluster- security command.
- CVE-2022-37890, CVE-2022-37891, CVE-2022-37892, CVE-2022-37895, and CVE-2022-37896: Restrict the web-based management interface to a dedicated layer 2 segment/VLAN and/or control the interface by firewall policies at layer 3 and above.
- CVE-2022-37893: Restrict the command line interface to a dedicated layer 2 segment/VLAN and/or control the interface by firewall policies at layer 3 and above.
As a general security measure, Siemens recommends protecting network access to devices with appropriate mechanisms. In order to operate the devices in a protected IT environment, Siemens recommends configuring the environment according to Siemens' operational guidelines for industrial security and following the recommendations in the product manuals.
Additional information on Industrial Security by Siemens can be found at the Siemens website.
For more information, see the associated Siemens security advisory SSA-506569 in HTML and CSAF.
Siemens SCALANCE W1750D is a brand-labeled device from Aruba. For more information regarding these vulnerabilities, see the Aruba security advisory ARUBA-PSA-2022-014.
Plugin Details
Supported Sensors: Tenable OT Security
Risk Information
Vector: CVSS2#AV:N/AC:L/Au:N/C:N/I:N/A:P
Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Temporal Vector: CVSS:3.0/E:P/RL:O/RC:C
Vulnerability Information
CPE: cpe:/o:siemens:scalance_w1750d_firmware
Required KB Items: Tenable.ot/Siemens
Exploit Ease: Exploits are available
Patch Publication Date: 11/11/2021
Vulnerability Publication Date: 11/11/2021