7.8 High
CVSS2
Attack Vector
NETWORK
Attack Complexity
LOW
Authentication
NONE
Confidentiality Impact
NONE
Integrity Impact
NONE
Availability Impact
COMPLETE
AV:N/AC:L/Au:N/C:N/I:N/A:C
7.5 High
CVSS3
Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
NONE
Integrity Impact
NONE
Availability Impact
HIGH
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
8.2 High
AI Score
Confidence
High
0.002 Low
EPSS
Percentile
64.4%
CVSS v3 7.5
**ATTENTION:**Exploitable remotely/low skill level to exploit
Vendor: Siemens
**Equipment:**EN100 Ethernet Communication Module and SIPROTEC 5 relays
Vulnerabilities: Improper Input Validation
This updated advisory is a follow-up to the original advisory titled ICSA-18-347-02 Siemens EN100 Ethernet Communication Module and SIPROTEC 5 Relays that was published December 13, 2018, on the NCCIC/ICS-CERT website.
Successful exploitation of these vulnerabilities could cause a denial-of-service condition of the network functionality of the device, compromising the availability of the system.
Siemens reports the vulnerabilities affect the following versions of the EN100 Ethernet Communication Module and SIPROTEC 5 relays:
--------- Begin Update A Part 1 of 2 --------
--------- End Update A Part 1 of 2 --------
Some products are only affected by one of the two vulnerabilities. Please see Siemens advisory SSA-635129 for additional details.
Specially crafted packets to Port 102/TCP could cause a denial-of-service condition in the affected products. A manual restart is required to recover the EN100 module functionality of SIPROTEC 4 and SIPROTEC Compact relays.
Successful exploitation requires an attacker with network access to send multiple packets to the affected products or modules. As a precondition, the IEC 61850-MMS communication needs to be activated on the affected products or modules. No user interaction or privileges are required to exploit the vulnerability.
CVE-2018-11451 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:N/I:N/A:H).
Specially crafted packets to Port 102/TCP could cause a denial-of-service condition in the EN100 communication module if oscillographs are running. A manual restart is required to recover the EN100 module functionality.
Successful exploitation requires an attacker with network access to send multiple packets to the EN100 module. As a precondition, the IEC 61850-MMS communication needs to be activated on the affected EN100 modules. No user interaction or privileges are required to exploit the security vulnerability.
CVE-2018-11452 has been assigned to this vulnerability. A CVSS v3 base score of 5.9 has been calculated; the CVSS vector string is (AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H).
Victor Nikitin, Vladislav Suchkov, and Ilya Karpov from ScadaX reported these vulnerabilities to Siemens.
Siemens has released updates for several affected products. Siemens is working on updates for the remaining affected products, and recommends specific countermeasures until fixes are available.
--------- Begin Update A Part 2 of 2 --------
--------- Begin Update A Part 2 of 2 --------
The firmware version for the communications modules can also be found on each deviceβs download page. Applying the update causes the device / module / program to undergo a single restart cycle.
Siemens strongly recommends applying the provided security updates using the corresponding tooling and documented procedures made available with the product. If supported by the product, an automated means to apply the security updates across multiple product instances may be used. Siemens strongly recommends prior validation of any security update before being applied, and supervision by trained staff of the update process in the target environment.
Until updates can be applied, Siemens recommends blocking access to Port 102/TCP with an external firewall.
As a general security measure Siemens strongly recommends protecting network access with appropriate mechanisms (e.g. firewalls, segmentation, VPN). It is advised that users configure the environment according to Siemens operational guidelines in order to run the devices in a protected IT environment.
Siemens recommended security guidelines to secure substations can be found at:
<https://www.siemens.com/gridsecurity>
Additional information on industrial security by Siemens can be found at:
<https://www.siemens.com/industrialsecurity>
For more information on this vulnerability and associated software updates, please see Siemens security advisory SSA-635129 on their website:
<https://www.siemens.com/cert/advisories>
NCCIC recommends users take defensive measures to minimize the risk of exploitation of this vulnerability. Specifically, users should:
NCCIC reminds organizations to perform proper impact analysis and risk assessment prior to deploying defensive measures.
NCCIC also provides a section for control systems security recommended practices on the ICS-CERT web page. Several recommended 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-CERT website in the Technical Information Paper, ICS-TIP-12-146-01BβTargeted Cyber Intrusion Detection and Mitigation Strategies.
Organizations observing any suspected malicious activity should follow their established internal procedures and report their findings to NCCIC for tracking and correlation against other incidents.
No known public exploits specifically target these vulnerabilities.
web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2018-11451
web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2018-11452
cwe.mitre.org/data/definitions/20.html
cwe.mitre.org/data/definitions/20.html
public.govdelivery.com/accounts/USDHSCISA/subscriber/new?topic_id=USDHSCISA_138
support.industry.siemens.com/cs/us/en/view/109745821
support.industry.siemens.com/cs/us/en/view/109745821
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7.8 High
CVSS2
Attack Vector
NETWORK
Attack Complexity
LOW
Authentication
NONE
Confidentiality Impact
NONE
Integrity Impact
NONE
Availability Impact
COMPLETE
AV:N/AC:L/Au:N/C:N/I:N/A:C
7.5 High
CVSS3
Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
NONE
Integrity Impact
NONE
Availability Impact
HIGH
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
8.2 High
AI Score
Confidence
High
0.002 Low
EPSS
Percentile
64.4%