# ICS Advisory (ICSA-20-042-06)
## Siemens SIMATIC PCS 7, SIMATIC WinCC, and SIMATIC NET PC (Update E)
Original release date: September 08, 2020
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* * *
## 1\. EXECUTIVE SUMMARY
* **CVSS v3 7.5**
* **ATTENTION:** Exploitable remotely/low skill level to exploit
* **Vendor:** Siemens
* **Equipment:** SIMATIC PCS 7, SIMATIC WinCC, SIMATIC NET PC
* **Vulnerability:** Incorrect Calculation of Buffer Size
## 2\. UPDATE INFORMATION
This updated advisory is a follow-up to the advisory update titled 20-042-06
Siemens SIMATIC PCS 7, SIMATIC WinCC, and SIMATIC NET PC (Update D) that was
published July 14, 2020, to the ICS webpage on us-cert.gov.
## 3\. RISK EVALUATION
Successful exploitation of this vulnerability could allow an attacker with
network access to cause a denial-of-service condition.
## 4\. TECHNICAL DETAILS
### 4.1 AFFECTED PRODUCTS
**\--------- Begin Update E Part 1 of 2 ---------**
The following versions of SIMATIC software are affected:
* OpenPCS 7 v8.1: all versions
* OpenPCS 7 v8.2: all versions
* OpenPCS 7 v9.0: all versions prior to v9.0 Upd3
* SIMATIC BATCH v8.1: all versions
* SIMATIC BATCH v8.2: all versions
* SIMATIC BATCH v9.0: all versions prior to v9.0 SP1 Upd5
* SIMATIC NET PC Software: all versions prior to v16 update 1
* SIMATIC PCS 7 v8.1: all versions
* SIMATIC PCS 7 v8.2: all versions
* SIMATIC PCS 7 v9.0: all versions prior to v9.0 SP3
* SIMATIC Route Control v8.1: all versions
* SIMATIC Route Control v8.2: all versions
* SIMATIC Route Control v9.0: all versions prior to v9.0 Upd4
* SIMATIC WinCC (TIA Portal) v13: all versions prior to v13 SP2
* SIMATIC WinCC (TIA Portal) v14: all versions
* SIMATIC WinCC (TIA Portal) v15.1: all versions prior to v15.1 Update 5
* SIMATIC WinCC (TIA Portal) v16: all versions prior to v16 Update 1
* SIMATIC WinCC v7.3: all versions
* SIMATIC WinCC v7.4: all versions prior to v7.4 SP1 Update 14
* SIMATIC WinCC v7.5: all versions prior to v7.5.1 Upd1
**\--------- End Update E Part 1 of 2 ---------**
### 4.2 VULNERABILITY OVERVIEW
#### 4.2.1 [INCORRECT CALCULATION OF BUFFER SIZE
CWE-131](https://cwe.mitre.org/data/definitions/131.html)
Through specially crafted messages, when encrypted communication is enabled,
an attacker with network access could compromise the availability of the
system by causing a denial-of-service condition.
[CVE-2019-19282](http://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2019-19282)
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](https://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)).
### 4.3 BACKGROUND
* **CRITICAL INFRASTRUCTURE SECTORS:** Chemical, Critical Manufacturing, Energy, Food and Agriculture, Water and Wastewater Systems
* **COUNTRIES/AREAS DEPLOYED:** Worldwide
* **COMPANY HEADQUARTERS LOCATION:** Germany
### 4.4 RESEARCHER
Nicholas Miles from Tenable reported this vulnerability to Siemens.
## 5\. MITIGATIONS
Siemens has identified the following specific workarounds and mitigations:
* Apply cell protection concept
* Use VPN for protecting network communication between cells
* Apply Defense-in-Depth
* For SIMATIC PCS 7 v9.0, Siemens recommends affected users update to v9.0 SP3 (Includes OpenPCS 7 v9.0 Upd3, SIMATIC Batch v9.0 Upd5, SIMATIC Route Control v9.0 Upd4). To obtain this update, contact Siemens customer service.
* For SIMATIC NET PC Software, Siemens recommends affected users update to [v16 update 1 or higher](https://support.industry.siemens.com/cs/ww/en/view/109778547)
* For SIMATIC WinCC (TIA Portal) v13, Siemens recommends affected users update to [v13 SP2 or higher](https://support.industry.siemens.com/cs/ww/en/view/109759782)
**\--------- Begin Update E Part 2 of 2 ---------**
* For SIMATIC WinCC (TIA Portal) v15.1: update to [v15.1 Update 5 or later version](https://support.industry.siemens.com/cs/us/en/)
**\--------- End Update E Part 2 of 2 ---------**
* For SIMATIC WinCC (TIA Portal) v16, Siemens recommends affected users update to [v16 update 1 or higher](https://support.industry.siemens.com/cs/ww/en/view/109778547)
* For SIMATIC WinCC v7.4, Siemens recommends affected users update to [v7.4 SP1 Update 14 or higher](https://support.industry.siemens.com/cs/us/en/)
* For SIMATIC WinCC v7.5, Siemens recommends affected users update to [v7.5.1 Upd1 or higher](https://support.industry.siemens.com/cs/ww/en/view/109773812)
Siemens has identified the following specific workarounds and mitigations:
* Apply cell protection concept
* Use VPN for protecting network communication between cells
* Apply defense-in-depth
For more information on this vulnerability and associated software updates,
please see Siemens security advisory
[SSA-270778](ttps://www.siemens.com/cert/advisories)
CISA recommends users take defensive measures to minimize the risk of
exploitation of this vulnerability. Specifically, users should:
* Minimize network exposure for all control system devices and/or systems, and ensure that they are [not accessible from the Internet](https://www.us-cert.gov/ics/alerts/ICS-ALERT-10-301-01).
* Locate control system networks and remote devices behind firewalls, and isolate them from the business network.
* When remote access is required, use secure methods, such as Virtual Private Networks (VPNs), recognizing that VPNs may have vulnerabilities and should be updated to the most current version available. Also recognize that VPN is only as secure as the 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](https://www.us-cert.gov/ics/recommended-practices) on the ICS
webpage on [us-cert.gov](https://www.us-cert.gov/ics). Several recommended
practices are available for reading and download, including [Improving
Industrial Control Systems Cybersecurity with Defense-in-Depth
Strategies](https://www.us-
cert.gov/sites/default/files/recommended_practices/NCCIC_ICS-
CERT_Defense_in_Depth_2016_S508C.pdf).
Additional mitigation guidance and recommended practices are publicly
available on the [ICS webpage on us-cert.gov](https://www.us-cert.gov/ics) in
the Technical Information Paper, [ICS-TIP-12-146-01B--Targeted Cyber Intrusion
Detection and Mitigation Strategies](https://www.us-cert.gov/ics/tips/ICS-
TIP-12-146-01B).
Organizations observing any suspected malicious activity should follow their
established internal procedures and report their findings to CISA for tracking
and correlation against other incidents.
No known public exploits specifically target this vulnerability.
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