Siemens SCALANCE and RUGGEDCOM Covert Timing Channel (CVE-2025-27587)

medium Tenable OT Security Plugin ID 505127

Synopsis

The remote OT asset is affected by a vulnerability.

Description

OpenSSL 3.0.0 through 3.3.2 on the PowerPC architecture is vulnerable to a Minerva attack, exploitable by measuring the time of signing of random messages using the EVP_DigestSign API, and then using the private key to extract the K value (nonce) from the signatures. Next, based on the bit size of the extracted nonce, one can compare the signing time of full-sized nonces to signatures that used smaller nonces, via statistical tests. There is a side-channel in the P-364 curve that allows private key extraction (also, there is a dependency between the bit size of K and the size of the side channel). NOTE:
This CVE is disputed because the OpenSSL security policy explicitly notes that any side channels which require same physical system to be detected are outside of the threat model for the software. The timing signal is so small that it is infeasible to be detected without having the attacking process running on the same physical system.

This plugin only works with Tenable.ot.
Please visit https://www.tenable.com/products/tenable-ot for more information.

Solution

Refer to the vendor advisory.

Plugin Details

Severity: Medium

ID: 505127

File Name: tenable_ot_siemens_CVE-2025-27587.nasl

Version: 1.2

Type: remote

Family: Tenable.ot

Published: 2/10/2026

Updated: 2/11/2026

Supported Sensors: Tenable OT Security

Risk Information

VPR

Risk Factor: Low

Score: 3.6

CVSS v3

Risk Factor: Medium

Base Score: 5.3

Temporal Score: 4.6

Vector: CVSS:3.0/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:N

Temporal Vector: CVSS:3.0/E:U/RL:O/RC:C

Vulnerability Information

CPE: cpe:/o:siemens:scalance_xrm334_%28230_v_ac%2c_8xfo%29_firmware:3.3, cpe:/o:siemens:scalance_xcm324_firmware:3.3, cpe:/o:siemens:scalance_xrm334_%2824v_dc%2c_2x10g%2c_24xsfp%2c_8xsfp%2b%29_firmware:3.3, cpe:/o:siemens:scalance_xrm334_%2824_v_dc%2c_8xfo%29_firmware:3.3, cpe:/o:siemens:scalance_xcm328_firmware:3.3, cpe:/o:siemens:scalance_xrm334_%28230_v_ac%2c_12xfo%29_firmware:3.3, cpe:/o:siemens:scalance_xrm334_%2824_v_dc%2c_12xfo%29_firmware:3.3, cpe:/o:siemens:scalance_xrm334_%28230v_ac%2c_2x10g%2c_24xsfp%2c_8xsfp%2b%29_firmware:3.3, cpe:/o:siemens:scalance_xrm334_%282x230v_ac%2c_2x10g%2c_24xsfp%2c_8xsfp%2b%29_firmware:3.3, cpe:/o:siemens:scalance_xrm334_%282x230_v_ac%2c_8xfo%29_firmware:3.3, cpe:/o:siemens:scalance_xrh334_%2824_v_dc%2c_8xfo%2c_cc%29_firmware:3.3, cpe:/o:siemens:ruggedcom_rst2428p_firmware:3.3, cpe:/o:siemens:scalance_xcm332_firmware, cpe:/o:siemens:scalance_xrm334_%282x230_v_ac%2c_12xfo%29_firmware:3.3, cpe:/o:siemens:scalance_xch328_firmware:3.3

Required KB Items: Tenable.ot/Siemens

Exploit Ease: No known exploits are available

Patch Publication Date: 1/28/2026

Vulnerability Publication Date: 5/22/2025

Reference Information

CVE: CVE-2025-27587

CWE: 385

Detections

Analytics