**ATTENTION:**Remotely exploitable/low skill level to exploit.
**Vendor:**Siemens
**Equipment:**SIMATIC WinCC Add-On
**Vulnerabilities:**Stack-based Buffer Overflow, Improper Input Validation, Improper Restriction of Operations within the Bounds of a Memory Buffer, Security Features, Improper Access Control.
This updated advisory is a follow-up to the original advisory titled ICSA-18-018-01 Siemens SIMATIC WinCC Add-On that was published January 18, 2018, on the NCCIC/ICS-CERT website.
Siemens reports that the vulnerabilities affect the following versions of SIMATIC WinCC Add-On:
Successful exploitation of these vulnerabilities could allow remote code execution or a denial of service condition.
Gemalto has released an updated installer and Siemens strongly encourages users upgrade to the new installer as soon as possible. The new installer is available at:
https://supportportal.gemalto.com/csm/?id=kb_article&sys_id=a459d328dba207c8fe0aff3dbf9619ce
Siemens also advises that users configure the operational environment according to Siemensβ Operational Guidelines for Industrial Security:
<https://www.siemens.com/cert/operational-guidelines-industrial-security>
For more information on these vulnerabilities and more detailed mitigation instructions, please see Siemens Security Advisory SSA-127490 at the following location:
<http://www.siemens.com/cert/advisories>
NCCIC recommends users take defensive measures to minimize the risk of exploitation of these vulnerabilities. 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 in the NCCIC Technical Information Paper, ICS-TIP-12-146-01BβTargeted Cyber Intrusion Detection and Mitigation Strategies, that is available for download from the ICS-CERT website.
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.
Malformed ASN1 streams in V2C and similar input files can be used to generate stack-based buffer overflows. The vulnerability could allow arbitrary code execution.
CVE-2017-11496 has been assigned to this vulnerability. A CVSS v3 base score of 9.8 has been assigned; the CVSS vector string is (AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H).
Language packs containing malformed filenames could lead to a stack-based buffer overflow. The vulnerability could allow arbitrary code execution.
CVE-2017-11497 has been assigned to this vulnerability. A CVSS v3 base score of 9.8 has been assigned; the CVSS vector string is (AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H).
Language pack (ZIP file) with invalid HTML files could lead to NULL pointer access. The vulnerability could cause denial of service of the remote process.
CVE-2017-11498 has been assigned to this vulnerability. A CVSS v3 base score of 7.5 has been assigned; the CVSS vector string is (AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H).
--------- Begin Update A Part 1 of 1 --------
A stack overflow flaw in the custom XML parser could allow remote denial of service.
CVE-2017-12818 has been assigned to this vulnerability. A CVSS v3 base score of 7.5 has been assigned; the CVSS vector string is (AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H).
Remote manipulation of the language pack updater could allow NTLM relay attacks.
CVE-2017-12819 has been assigned to this vulnerability. A CVSS v3 base score of 9.8 has been assigned; the CVSS vector string is (AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H).
Arbitrary memory read from controlled memory pointer could allow remote denial of service.
CVE-2017-12820 has been assigned to this vulnerability. A CVSS v3 base score of 7.5 has been assigned; the CVSS vector string is (AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H).
A memory corruption flaw could allow remote code execution.
CVE-2017-12821 has been assigned to this vulnerability. A CVSS v3 base score of 9.8 has been assigned; the CVSS vector string is (AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H).
The administrative interface can be remotely enabled and disabled without authentication. This could increase the attack surface.
CVE-2017-12822 has been assigned to this vulnerability. A CVSS v3 base score of 5.3 has been assigned; the CVSS vector string is (AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N).
--------- End Update A Part 1 of 1 ----------
Sergey Temnikov and Vladimir Dashchenko from Kaspersky Lab reported these vulnerabilities to Siemens.
**Critical Infrastructure Sectors:**Chemical, Energy, Food and Agriculture, Water and Wastewater Systems.
**Countries/Areas Deployed:**Worldwide
**Company Headquarters Location:**Germany
ics-cert.us-cert.gov
ics-cert.us-cert.gov
twitter.com/icscert
twitter.com/icscert
www.addthis.com/bookmark.php?url=https%3A%2F%2Fics-cert.us-cert.gov%2Fadvisories%2FICSA-18-018-01A
www.dhs.gov
www.dhs.gov/report-cyber-risks
www.siemens.com/cert/advisories
www.us-cert.gov/accessibility/
www.us-cert.gov/pdf/
www.us-cert.gov/privacy/
www.us-cert.gov/tlp/
www.us-cert.gov/tlp/
cwe.mitre.org/data/definitions/119.html
cwe.mitre.org/data/definitions/119.html
cwe.mitre.org/data/definitions/119.html
cwe.mitre.org/data/definitions/121.html
cwe.mitre.org/data/definitions/121.html
cwe.mitre.org/data/definitions/20.html
cwe.mitre.org/data/definitions/254.html
cwe.mitre.org/data/definitions/284.html
ics-cert.us-cert.gov/
ics-cert.us-cert.gov/alerts/ICS-ALERT-10-301-01
ics-cert.us-cert.gov/content/recommended-practices
ics-cert.us-cert.gov/Report-Incident?
ics-cert.us-cert.gov/sites/default/files/recommended_practices/NCCIC_ICS-CERT_Defense_in_Depth_2016_S508C.pdf
ics-cert.us-cert.gov/tips/ICS-TIP-12-146-01B
nvd.nist.gov/vuln/detail/CVE-2017-11496
nvd.nist.gov/vuln/detail/CVE-2017-11497
nvd.nist.gov/vuln/detail/CVE-2017-11498
nvd.nist.gov/vuln/detail/CVE-2017-12818
nvd.nist.gov/vuln/detail/CVE-2017-12819
nvd.nist.gov/vuln/detail/CVE-2017-12820
nvd.nist.gov/vuln/detail/CVE-2017-12821
nvd.nist.gov/vuln/detail/CVE-2017-12822
supportportal.gemalto.com/csm/?id=kb_article&sys_id=a459d328dba207c8fe0aff3dbf9619ce
twitter.com/share?url=https%3A%2F%2Fics-cert.us-cert.gov%2Fadvisories%2FICSA-18-018-01A
www.facebook.com/sharer.php?u=https%3A%2F%2Fics-cert.us-cert.gov%2Fadvisories%2FICSA-18-018-01A
www.first.org/cvss/calculator/3.0#CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
www.first.org/cvss/calculator/3.0#CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
www.first.org/cvss/calculator/3.0#CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
www.first.org/cvss/calculator/3.0#CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
www.first.org/cvss/calculator/3.0#CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
www.first.org/cvss/calculator/3.0#CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
www.first.org/cvss/calculator/3.0#CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
www.first.org/cvss/calculator/3.0#CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
www.siemens.com/cert/operational-guidelines-industrial-security
www.us-cert.gov/forms/feedback?helpful=no&document=ICSA-18-018-01A Siemens SIMATIC WinCC Add-On (Update A)&trackingNumber=&url=https://ics-cert.us-cert.gov/advisories/ICSA-18-018-01A&site_name=ICS-CERT
www.us-cert.gov/forms/feedback?helpful=somewhat&document=ICSA-18-018-01A Siemens SIMATIC WinCC Add-On (Update A)&trackingNumber=&url=https://ics-cert.us-cert.gov/advisories/ICSA-18-018-01A&site_name=ICS-CERT
www.us-cert.gov/forms/feedback?helpful=yes&document=ICSA-18-018-01A Siemens SIMATIC WinCC Add-On (Update A)&trackingNumber=&url=https://ics-cert.us-cert.gov/advisories/ICSA-18-018-01A&site_name=ICS-CERT