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AUSCERT External Security Bulletin Redistribution
ESB-2023.1791
ICS Advisory (ICSA-23-082-03) SAUTER EY-modulo 5 Building
Automation Stations
24 March 2023
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AusCERT Security Bulletin Summary
---------------------------------
Product: EY-modulo 5 Building Automation Stations
Publisher: ICS-CERT
Operating System: Network Appliance
Resolution: Mitigation
CVE Names: CVE-2023-28655 CVE-2023-28652 CVE-2023-28650
CVE-2023-27927 CVE-2023-22300
Original Bulletin:
https://www.cisa.gov/news-events/ics-advisories/icsa-23-082-03
Comment: CVSS (Max): 8.8 CVE-2023-28650 (CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H)
CVSS Source: ICS-CERT
Calculator: https://www.first.org/cvss/calculator/3.0#CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
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ICS Advisory (ICSA-23-082-03)
SAUTER EY-modulo 5 Building Automation Stations
Release Date
March 23, 2023
1. EXECUTIVE SUMMARY
o CVSS v3 8.8
o ATTENTION: Exploitable remotely/low attack complexity
o Vendor: SAUTER
o Equipment: EY-modulo 5 Building Automation Stations
o Vulnerabilities: Cross-site Scripting, Cleartext Transmission of Sensitive
Information, and Unrestricted Upload of File with Dangerous Type
2. RISK EVALUATION
Successful exploitation of these vulnerabilities could lead to privilege
escalation, unauthorized execution of actions, a denial-of-service condition,
or retrieval of sensitive information.
3. TECHNICAL DETAILS
3.1 AFFECTED PRODUCTS
SAUTER reports these vulnerabilities affect the following EY-modulo 5 Building
Automation Stations:
o EY-AS525F001 with moduWeb
3.2 VULNERABILITY OVERVIEW
3.2.1 CROSS-SITE SCRIPTING CWE-79
An unauthenticated remote attacker could provide a malicious link and trick an
unsuspecting user into clicking on it. If clicked, the attacker could execute
the malicious JavaScript (JS) payload in the target's security context.
CVE-2023-28650 has been assigned to this vulnerability. A CVSS v3 base score of
8.8 has been calculated; the CVSS vector string is ( AV:N/AC:L/PR:N/UI:R/S:U/
C:H/I:H/A:H ).
3.2.2 CROSS-SITE SCRIPTING CWE-79
A malicious user could leverage this vulnerability to escalate privileges or
perform unauthorized actions in the context of the targeted privileged users.
CVE-2023-28655 has been assigned to this vulnerability. A CVSS v3 base score of
8.0 has been calculated; the CVSS vector string is ( AV:N/AC:L/PR:L/UI:R/S:U/
C:H/I:H/A:H ).
3.2.3 CROSS-SITE SCRIPTING CWE-79
An unauthenticated remote attacker could force all authenticated users, such as
administrative users, to perform unauthorized actions by viewing the logs. This
action would also grant the attacker privilege escalation.
CVE-2023-22300 has been assigned to this vulnerability. A CVSS v3 base score of
8.8 has been calculated; the CVSS vector string is ( AV:N/AC:L/PR:N/UI:R/S:U/
C:H/I:H/A:H ).
3.2.4 CLEARTEXT TRANSMISSION OF SENSITIVE INFORMATION CWE-319
An authenticated malicious user could acquire the simple mail transfer protocol
(SMTP) Password in cleartext format, despite it being protected and hidden
behind asterisks. The attacker could then perform further attacks using the
SMTP credentials.
CVE-2023-27927 has been assigned to this vulnerability. A CVSS v3 base score of
7.5 has been calculated; the CVSS vector string is ( AV:N/AC:L/PR:N/UI:N/S:U/
C:H/I:N/A:N ).
3.2.5 UNRESTRICTED UPLOAD OF FILE WITH DANGEROUS TYPE CWE-434
An authenticated malicious user could successfully upload a malicious image
could lead to a denial-of-service condition.
CVE-2023-28652 has been assigned to this vulnerability. A CVSS v3 base score of
6.5 has been calculated; the CVSS vector string is ( AV:N/AC:L/PR:L/UI:N/S:U/
C:N/I:N/A:H ).
3.3 BACKGROUND
o CRITICAL INFRASTRUCTURE SECTORS: Critical Manufacturing, Energy
o COUNTRIES/AREAS DEPLOYED: Worldwide
o COMPANY HEADQUARTERS LOCATION: Switzerland
3.4 RESEARCHER
Ithaca Labs of Odyssey Cyber Security reported this vulnerability to CISA.
4. MITIGATIONS
According to SAUTER, the EY-modulo 5 Building Automation Stations product line
does not support encryption on its communication protocols. As such, it is not
appropriate for open networks.
SAUTER recommends deactivating moduWeb when not in use as doing so closes the
vulnerabilities related to the web server and the mail client service; users
can upgrade to the latest generation modulo 6 with moduWeb Unity as the web
server, which supports encrypted communication with TLS.
SAUTER recommends users take all necessary measures to protect the integrity of
building automation networks, restrict access to the devices, and leverage all
appropriate means and policies to minimize risks. Users should evaluate and
upgrade legacy systems to current solutions where necessary.
CISA recommends users take defensive measures to minimize the risk of
exploitation of these vulnerabilities. Specifically, users should:
o Minimize network exposure for all control system devices and/or systems,
and ensure they are not accessible from the Internet .
o Locate control system networks and remote devices behind firewalls and
isolate them from business networks.
o When remote access is required, use secure methods, such as Virtual Private
Networks (VPNs), recognizing VPNs may have vulnerabilities and should be
updated to the most current version available. Also recognize VPN is only
as secure as its connected devices.
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-12-146-01B--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.
CISA also recommends users take the following measures to protect themselves
from social engineering attacks:
o Do not click web links or open attachments in unsolicited email messages.
o Refer to Recognizing and Avoiding Email Scams for more information on
avoiding email scams.
o Refer to Avoiding Social Engineering and Phishing Attacks for more
information on social engineering attacks.
No known public exploits specifically target these vulnerabilities. These
vulnerabilities are exploitable remotely. These vulnerabilities have low attack
complexity.
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