Siemens Fixes Vulnerabilities in SIMATIC WinCC SCADA System

Siemens has released version 7.3 of the SIMATIC WinCC supervisory control and data acquisition (SCADA) system to address several vulnerabilities, most of which can be exploited remotely.

According to advisories published by both Siemens and ICS-CERT last week, the vulnerabilities affect all prior versions of SIMATIC WinCC, a SCADA system that’s used to monitor and control physical processes in industries such as chemical, food and beverage, oil and gas, and water.

The first vulnerability (CVE-2014-4682), described as a “forced browsing” issue, affects the SIMATIC WinCC WebNavigator server. An attacker could gain unauthenticated access to sensitive data by sending specially crafted HTTP requests to Port 80/TCP or Port 443/TCP. An attacker could also escalate privileges in WinCC due to an issue in the access control settings of the WebNavigator server at Port 80/TCP and Port 443/TCP (CVE-2014-4683).

Additionally, an improper privilege management issue (CVE-2014-4684) can be leveraged to escalate privileges in the SIMATIC WinCC database server by sending it a specially crafted command at Port 1433/TCP. Security researchers also found a way to escalate privileges in the WinCC Project administration application with the aid of a hard-coded cryptographic key that can be obtained by intercepting a legitimate user’s network traffic on Port 1030/TCP (CVE-2014-4686).

The last vulnerability (CVE-2014-4685), the only one that can’t be exploited remotely, is related to permissions, privileges and access controls.

“Access permissions on system objects could allow a local user to obtain limited escalated privileges within the operating system,” Siemens and ICS-CERT said in their advisories.

Siemens has clarified that the vulnerabilities can only be exploited if the attacker has network access to the corresponding port. Furthermore, authenticated access is required for CVE-2014-4683 and CVE-2014-4684.

Sergey Gordeychik, Alexander Tlyapov, Dmitry Nagibin, and Gleb Gritsai of Positive Technologies and an anonymous researcher have been credited for finding and reporting the security holes.

The flaws also affect the SIMATIC PCS7 distributed control system, versions prior to 8.1, because WinCC is incorporated into the product. However, SIMATIC PCS7 8.1 will only be released in the months ahead, Siemens said.

ICS-CERT says it’s not aware of publicly available exploits that target these vulnerabilities. However, organizations are advised to update their installations as soon as possible, or apply certain steps described in the security advisories to mitigate the risk.

Earlier this month, Siemens released updates for several of its industrial products to address four recently patched OpenSSL vulnerabilities.