Siemens has released firmware and software updates to address a couple of vulnerabilities affecting some of the company’s SIMATIC industrial automation products.
According to advisories published this week by both ICS-CERT and Siemens, Mate Csorba of DNV GL and Amund Sole of Norwegian University of Science and Technology discovered that SIMATIC S7-300 programmable logic controllers (PLCs) are plagued by a high severity denial-of-service (DoS) flaw.
The security hole, tracked as CVE-2016-3949 and assigned a CVSS v3 score of 7.5, can be exploited by an attacker to cause the targeted device to enter defect mode by sending it specially crafted packets via the PROFIBUS (Process Field Bus) or Port 102/TCP. The user must perform a cold restart in order to restore the system after such an attack.
While this is considered a high severity issue, Siemens pointed out that the attacker needs to have network access to the targeted device. Furthermore, the attack does not work if protection level 3 (read/write protection) is enabled.
The vulnerability has been patched with the release of firmware versions 3.2.12 (with Profinet support) and 3.3.12 (without Profinet support), and Siemens recommends operating the PLCs only on trusted networks.
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A separate advisory published by ICS-CERT and Siemens describes a low severity vulnerability (CVE-2015-1358) affecting SIMATIC WinCC flexible panels and runtime systems used for process visualization and control operations.
Gleb Gritsai and Roman Ilin from Positive Technologies discovered that the product doesn’t properly protect credentials when transmitting them on the network. This could allow a man-in-the-middle (MitM) attacker to obtain the information.
The flaw impacts SIMATIC WinCC flexible 2008 SP3 and it has been resolved with the release of Update 7. ICS-CERT noted that only a highly skilled attacker could exploit this vulnerability.
Related: Vulnerabilities Found in Siemens SIPROTEC Protection Relays