---
title: "Siemens Building X Flaw Allows Firmware Tampering: CVE-2022-31807 Explained"
short_title: "Siemens Building X firmware tampering vulnerability"
description: "Siemens Building X Security Manager Edge Controller flaw (CVE-2022-31807) enables attackers to upload malicious firmware. Learn mitigation steps and risk details now."
author: "Vitus"
date: 2025-01-24
categories: [Cybersecurity, Vulnerabilities]
tags: [siemens, cve-2022-31807, firmware, industrial-security, vulnerability]
score: 0.65
cve_ids: [CVE-2022-31807]
---
TL;DR
Siemens has disclosed a critical vulnerability (CVE-2022-31807) in its Building X Security Manager Edge Controller, allowing attackers to upload maliciously modified firmware. The flaw stems from improper verification of cryptographic signatures and poses a significant risk to industrial environments. While no active exploitation has been reported, Siemens recommends immediate mitigation steps to prevent potential attacks.
---
Main Content
Introduction
Industrial cybersecurity remains a critical concern as vulnerabilities in operational technology (OT) systems can lead to severe disruptions. Siemens, a global leader in industrial automation, has recently highlighted a security flaw in its Building X Security Manager Edge Controller that could allow attackers to tamper with firmware. Identified as CVE-2022-31807, this vulnerability underscores the importance of robust security practices in critical infrastructure sectors.
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Key Points
- Vulnerability Impact: The flaw enables attackers to upload maliciously modified firmware onto affected devices, potentially compromising system integrity.
- Attack Complexity: The vulnerability has a low attack complexity, making it accessible to threat actors with local access or the ability to intercept firmware transfers.
- Affected Products: All versions of the Siemens Building X Security Manager Edge Controller (ACC-AP) are vulnerable.
- No Active Exploitation: As of now, there are no reported cases of this vulnerability being exploited in the wild.
- Mitigation Steps: Siemens has provided workarounds to reduce risk, including controlled firmware updates and network protection measures.
---
Technical Details
#### Affected Products
Siemens has confirmed that the following product is affected by CVE-2022-31807:
- Building X Security Manager Edge Controller (ACC-AP): All versions.
#### Vulnerability Overview
The vulnerability is classified as CWE-347: Improper Verification of Cryptographic Signature. Affected devices fail to properly verify the integrity of firmware updates, creating two primary attack scenarios:
1. Local Attack: A threat actor with access to the device could upload maliciously modified firmware.
2. Remote Interception: An attacker capable of intercepting firmware transfers between the server and the device could alter the firmware "on the fly."
#### CVSS Scores
- CVSS v3.1 Base Score: 6.2 (Medium Severity)
Vector: `CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N`
- CVSS v4.0 Base Score: 5.9 (Medium Severity)
Vector: `CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N`
#### Background Context
- Critical Infrastructure Sector: Critical Manufacturing
- Deployment: Worldwide
- Researcher: Siemens ProductCERT reported the vulnerability to CISA.
---
Impact Assessment
Successful exploitation of CVE-2022-31807 could have severe consequences for industrial environments:
- System Compromise: Attackers could gain unauthorized control over affected devices, leading to operational disruptions.
- Data Integrity Risks: Tampered firmware may introduce backdoors or malicious code, compromising data integrity and confidentiality.
- Operational Downtime: Unauthorized firmware modifications could result in system failures or unexpected behavior, causing downtime in critical processes.
While the vulnerability is not exploitable remotely, its low attack complexity and potential impact on critical infrastructure make it a significant concern.
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Mitigation Steps
Siemens has outlined the following workarounds and mitigations to reduce the risk of exploitation:
#### For Building X Security Manager Edge Controller (ACC-AP):
1. Controlled Firmware Updates:
- Use the ACC Firmware App to apply updates in a controlled and authenticated manner.
- Ensure firmware packages are downloaded only from the official SIOS portal.
- Validate firmware integrity by confirming hash values before installation.
2. Access Control:
- Limit access to the controller to authorized personnel only.
- Protect and regularly update credentials to prevent unauthorized access.
3. Network Protection:
- Follow Siemens' [operational guidelines for industrial security](https://www.siemens.com/cert/operational-guidelines-industrial-security) to protect network access.
- Isolate control system networks from business networks using firewalls.
- Avoid exposing control system devices to the internet.
#### General Recommendations from CISA:
- Minimize Network Exposure: Ensure control system devices are not accessible from the internet.
- Use Secure Remote Access: When remote access is required, use Virtual Private Networks (VPNs) and keep them updated.
- Implement Defensive Measures: Follow CISA’s [recommended practices for control systems security](https://www.cisa.gov/resources-tools/resources/ics-recommended-practices).
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Conclusion
The discovery of CVE-2022-31807 in Siemens Building X Security Manager Edge Controller highlights the ongoing risks faced by industrial systems. While no active exploitation has been reported, the vulnerability’s potential impact on critical infrastructure demands immediate action. Organizations using affected devices should apply Siemens’ mitigation recommendations and adhere to best practices for industrial cybersecurity to minimize risks.
For further details, refer to Siemens’ official security advisory [SSA-420375](https://cert-portal.siemens.com/productcert/html/ssa-420375.html) and CISA’s guidelines on [control systems security](https://www.cisa.gov/topics/industrial-control-systems).
---
References
[^1]: Siemens ProductCERT. "[SSA-420375: Building X - Security Manager Edge Controller (ACC-AP)](https://cert-portal.siemens.com/productcert/html/ssa-420375.html)". Retrieved 2025-01-24.
[^2]: CISA. "[ICS Advisory (ICSA-25-345-07): Siemens Building X](https://www.cisa.gov/news-events/ics-advisories/icsa-25-345-07)". Retrieved 2025-01-24.
[^3]: MITRE. "[CWE-347: Improper Verification of Cryptographic Signature](https://cwe.mitre.org/data/definitions/347.html)". Retrieved 2025-01-24.