IOServer Fixes Improper Input Validation

Friday, August 2, 2013 @ 04:08 PM gHale


IOServer created a new version that mitigates the improper input validation vulnerability in the DNP3 Driver on the master station, according to a report on ICS-CERT.

Researchers Adam Crain of Automatak and independent researcher Chris Sistrunk, who found the vulnerability, tested the new version to validate that it resolves the remotely exploitable vulnerability.

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The following IOServer product versions suffer from the issue:
• IOServer’s Beta2041.exe, and
• IOServer’s versions older than driver19.exe.

The master station device can fall into an infinite loop by sending a specially crafted TCP packet, known as “TCP Connection Hijacking.” The device must manually restart to recover from the loop condition.

IOServer is a New Zealand-based company that maintains users in several countries around the world, including the UK, Canada, New Zealand, Australia, Austria, France, Germany, Netherlands, Italy, India, Czech Republic, China, Singapore, South Korea, South Africa, and Brazil.

IOServer is a Windows-based OPC Server that allows OPC clients such as human-machine interface and supervisory control and data acquisition systems to exchange plant floor data with programmable logic circuits. IOServer said the affected products deploy across multiple sectors including manufacturing, building automation, oil and gas, water and wastewater, electric utilities, and others.

The IOServer driver does not validate or incorrectly validates input on the master server on Port 20000/TCP that can affect the control flow or data flow of a program. When this software does not validate input properly, an attacker is able to craft the input in a form not expected by the rest of the application. This will lead to parts of the system receiving unintended input, which may result in altered control flow or arbitrary control of a resource.

As a result, the IOServer enters an infinite loop condition without an exit. The user must then restart the system manually.

CVE-2013-2790 is the number assigned to this vulnerability, which has a CVSS v2 base score of 7.1.

There are no public exploits specifically targeting this vulnerability. An attacker with a moderate skill would be able to exploit this vulnerability.

IOServer release Beta driver beta2042.exe resolves this vulnerability. Version beta2043.exe has already superseded the other program. Click here for more information about this version of this product.

The researchers said one way to mitigate the problem is to block DNP3 traffic from traversing onto business or corporate networks through the use of an IPS or firewall with DPN3-specific rule sets.



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