Gessler GmbH WEB-MASTER

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1. EXECUTIVE SUMMARY

• CVSS v3 9.8
• ATTENTION: Exploitable Remotely/Low attack complexity
• Vendor: Gessler GmbH
• Equipment: WEB-MASTER
• Vulnerabilities: Use of Weak Credentials, Use of Weak Hash

2. RISK EVALUATION

Successful exploitation of these vulnerabilities could allow a user to take control of the web management of the device. An attacker with access to the device could also extract and break the password hashes for all users stored on the device.

3. TECHNICAL DETAILS

3.1 AFFECTED PRODUCTS

The following versions of Gessler GmbH WEB-MASTER, an emergency lighting management system, are affected:

• WEB-MASTER: version 7.9

3.2 Vulnerability Overview

3.2.1 USE OF WEAK CREDENTIALS CWE-1391

Gessler GmbH WEB-MASTER has a restoration account that uses weak hard coded credentials and if exploited could allow an attacker control over the web management of the device.

CVE-2024-1039 has been assigned to this vulnerability. A CVSS v3.1 base score of 9.8 has been calculated; the CVSS vector string is (AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H).

3.2.2 USE OF WEAK HASH CWE-328

Gessler GmbH WEB-MASTER user account is stored using a weak hashing algorithm. The attacker can restore the passwords by breaking the hashes stored on the device.

CVE-2024-1040 has been assigned to this vulnerability. A CVSS v3.1 base score of 4.4 has been calculated; the CVSS vector string is (AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:N/A:N).

3.3 BACKGROUND

• CRITICAL INFRASTRUCTURE SECTORS: Multiple
• COUNTRIES/AREAS DEPLOYED: Worlwide
• COMPANY HEADQUARTERS LOCATION: Germany

3.4 RESEARCHER

Felix Eberstaller and Nino Fürthauer of Limes Security reported these vulnerabilities to CISA.

4. MITIGATIONS

Gessler GmbH recommends updating EZ2 to 3.2 or greater and WebMaster to 4.4 or greater to mitigate these vulnerabilities. Updates have to be applied by Gessler GmbH technicians. For more information contact Gessler GmbH.

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/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.

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/ics 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.

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

5. UPDATE HISTORY

• February 1, 2024: Initial Publication