Three Advisories Published – 04-16-19

Yesterday the DHS NCCIC-ICS published two control system security advisories for products from WAGO and Delta Industrial Automation, and one for PLC products from multiple vendors.

PLC Advisory

This advisory describes an uncontrolled resource consumption vulnerability in specific PLC products from ABB, Phoenix Contact, Schneider Electric, Siemens, WAGO. The vulnerability was reported by Matthias Niedermaier (Hochschule Augsburg), Jan-Ole Malchow (Freie Universität Berlin), and Florian Fischer (Hochschule Augsburg). The responses range from a firmware update from Schneider, to ‘its not really a vulnerability but here are generic workarounds’, to ‘its not a vulnerability’ from Siemens. There is no indication that the researchers have been provided an opportunity to verify the efficacy of the fixes.

NCCIC-ICS reports that a relatively low-skilled attacker could use a publicly available exploit to emotely influence configured cycle times.

NOTE: The Schneider advisory referenced in this advisory was released in February and listed a 2018 CVE number for the reported vulnerability. Neither CVE number is currently available.

WAGO Advisory

This advisory describes a hard-coded credential vulnerability in the WAGO Series 750-88x and 750-87x PLCs. The vulnerability was reported by Jörn Schneeweisz of Recurity Labs. WAGO has new firmware that mitigates the vulnerability. There is no indication that Schneeweisz has been provided an opportunity to verify the efficacy of the fix.

NCCIC-ICS reports that a relatively low-skilled attacker could remotely exploit this vulnerability to change the settings or alter the programming of the device.

NOTE: I briefly mentioned this vulnerability last Saturday.

Delta Advisory

This advisory describes three vulnerabilities in the Delta Industrial Automation CNCSoft screen editor software. The vulnerabilities were reported by Natnael Samson and an anonymous researcher via the Zero Day Initiative. Delta has an updated version that mitigates the vulnerabilities. There is no indication that the researchers have been provided an opportunity to verify the efficacy of the fix.

The three reported vulnerabilities are:

• Stack-based buffer overflow - CVE-2019-10947;

• Heap-based buffer overflow - CVE-2019-10951; and

• Out-of-bounds read - CVE-2019-10949

NCCIC-ICS reports that a relatively low-skilled attacker with uncharacterized access could exploit this vulnerability to cause buffer overflow conditions that may allow information disclosure, remote code execution, or crash the application.

Public ICS Disclosures – Week of 08-11-18

This week we have three vendor disclosures from Yokogawa (2), and Belden and an advisory update from Siemens. There are also two disclosures from vdeCERT for products from Phoenix Contact and WAGO. Both of those disclosures pointed to an interesting research paper on “Measuring PLC Cycle Times under Attacks”.

Vnet/IP Network Switches Advisory

Yokogawa reports a debug vulnerability in their Vnet/IP network switches. The vulnerability is due to a third-party software issue (see Belden below). Yokogawa reports a work around since there “is no provision of firmware’s which are countermeasures against this vulnerability”.

License Management Advisory

Yokogawa reports a buffer overflow vulnerability in the license management function in a number of their products. Yokogawa has an update that mitigates the vulnerability. The advisory notes that ICS-CERT has been notified so there is a strong chance that this will be reported by ICS-CERT in the coming week.

Belden Advisory

Belden reports (.PDF Download) 16 separate vulnerabilities in the TCPdump functionality of their OWL industrial routers and HiOS ethernet switches. Belden provides a work around and notes that the TCPdump functionality is inactive by default.

NOTE: This advisory is actually dated July 27^th, 2018 (and outside of this week’s window), but because of its relation to the Yokogawa advisory it is being included here because of the potential for other vendors being affected. Also note that the CVE’s for the vulnerabilities date back to 2016 and 2017. That indicates that either it took a long time to figure out the minor workaround, or Belden was not really concerned about these vulnerabilities.

Siemens Update

Siemens updated their general customer advisory for the Spectre/Meltdown vulnerabilities. The advisory was last updated on July 17^th, 2018.This update adds information on the L1 Terminal Fault / Foreshadow versions of the vulnerabilities.

NOTE: The latest version (update H) of the ICS-CERT alert on Spectre/Meltdown still does not mention the newer variants of the vulnerabilities reported in this Siemens advisory.

Phoenix Contact Advisory

VDE-CERT reports an uncontrolled resource consumption vulnerability in the Phoenix Contact ILC 1x1 ETH. The vulnerability was reported by Matthias Niedermaier (Hochschule Augsburg), Jan-Ole Malchow (Freie Universität Berlin) and Florian Fischer (Hochschule Augsburg). A generic workaround has been provided.

WAGO Advisory

VDE-CERT reports an uncontrolled resource consumption vulnerability in the WAGO 750-8xx Controllers. he vulnerability was reported by Matthias Niedermaier (Hochschule Augsburg), Jan-Ole Malchow (Freie Universität Berlin) and Florian Fischer (Hochschule Augsburg). A generic workaround has been provided.

Measuring PLC Cycle Times under Attacks

The research paper that pointed out the Phoenix Contact and WAGO vulnerabilities discussed above provides an interesting look at the possibility of detecting on-going control-system attacks by monitoring PLC cycle times. As an academic look at this potential attack detection technique, this paper is well worth reading. From a process chemist’s point of view this points out a specific, unintended process problem, that these attacks might pose that also provide an indication of an on-going cyber-attack.

One of the problems that a process engineer/chemist has to deal with in designing a control system scheme in the chemical industry (and that is probably true for other industries as well) is the lag time between when a process indicator (sensor) notes that a process state needs to be changed and when the process actuator (valve for example) can complete its action to effect that change. A great deal of effort goes into ‘tuning’ the system to minimize the potential adverse impacts caused by that time lag.

This paper notes that a variety of attacks can affect the lag time within the PLC. Normally, this portion of the total lag time is small and nearly constant, so it is essentially ignored in the tuning process. This paper notes that in some attacks the lag time can be increased by up to several seconds (this can be an eternity in critical portions of many chemical reactions). To make things even more interesting it appears that TCPdump attacks (like those discussed in the Yokogawa and Belden advisories above) can actually speed-up the PLC processing and decrease the overall lag time, creating a whole new set of process problems.

This means that certain types of process upsets can be an indication of on-going cyber-attacks on control systems. To say the least, this complicates the job of the process overseers (another root cause possibility that needs to be examined), but it could provide control systems engineers with a warning to check their systems for other signs of attacks.

ICS-CERT Publishes 5 Advisories

Yesterday the DHS ICS-CERT published five control system security advisories for products from Schneider, Ctek, Digium, iniNet Solutions, and Saia Burgess Controls. The advisory for the products from Saia Burgess Controls was originally posted to the NCCIC Portal on August 22, 2017.

Saia Burgess Controls Advisory

This advisory describes an information exposure vulnerability in the Saia Burgess Controls PCD Controllers. The vulnerability was reported by Davide Fauri of Eindhoven University of Technology. The latest version of the firmware mitigates the vulnerability. There is no indication that Fauri has been provided an opportunity to verify the efficacy of the fix.

ICS-CERT reports that a relatively low skilled attacker could remotely exploit the vulnerability to to obtain information in memory.

The SBC upgrade notes also report that the current version makes the following security changes:

• Protective functions are activated by default;

• Improved password protection associated with the role-based user management;

• Access filter using "white" and "black" lists;

• Removed hardcoded password [NOT mentioned in ICS-CERT advisory].

Similar changes were also apparently made to the SBC PG5 Controls Suite.

iniNet Solutions Advisory

This advisory describes an improper authentication vulnerability in the iniNet Solutions SCADA Webserver. The vulnerability was reported by Matthias Niedermaier and Florian Fischer, both of Augsburg University of Applied Sciences. iniNet has released a new version that allows users to implement basic authentication. There is no indication that the researchers were afforded an opportunity to verify the efficacy of the fix.

ICS-CERT reports that a relatively low skilled attacker could remotely exploit the vulnerability  to access human-machine interface (HMI) pages or to modify programmable logic controller (PLC) variables without authentication.

Digium Advisory

This advisory describes an OS command injection vulnerability in the Digium Asterisk GUI. The vulnerability was reported by Davy Douhine of RandoriSec. Asterisk GUI is no longer maintained and should not be used. Digium recommends affected users to migrate to Digium’s SwitchVox product.

ICS-CERT reports that a relatively low skilled attacker could remotely exploit the vulnerability  to execute arbitrary code on the device.

Interesting Questions: Would owners of a control system that uses an HMI configured with Digium’s Asterix GUI even know that it had been used, particularly if the system had been designed by a contractor or vendor? Would it take a complete system redesign to change out the GUI for an HMI?

Ctek Advisory

This advisory describes an improper authentication vulnerability in the Ctek SkyRouter. The vulnerability was reported by Maxim Rupp. The latest firmware version mitigates this and “additional security requirements”. NOTE: “Ctek, Inc., reports that due to industry demand, wireless carriers are rapidly eliminating 2G and 3G CDMA service and they will not be creating any additional update releases for those products.” There is no indication that Rupp was provided an opportunity to verify the efficacy of the fix.

ICS-CERT reports that a relatively low skilled attacker could remotely exploit the vulnerability to view and edit settings without authenticating.

Schneider Advisory

This advisory describes a missing authentication for critical function vulnerability in the Schneider InduSoft Web Studio products. The vulnerability was reported by Aaron Portnoy, formerly of Exodus Intelligence. Schneider has created a patch to mitigate the vulnerability. There is no indication that Portnoy was provided an opportunity to verify the efficacy of the fix.

ICS-CERT reports that a relatively low skilled attacker could remotely exploit the vulnerability  to remotely execute arbitrary commands with high privileges.

NOTE: The Schneider security bulletin was published last Friday. Maybe Dale Peterson was right, it looks like ICS-CERT is doing ‘ICS-vuln Thursday’.