Siemens has new firmware and workarounds to handle improper restriction of operations within the bounds of a memory buffer, and session fixation vulnerabilities in its LOGO!8 devices, according to a report with NCCIC.
Successful exploitation of these remotely exploitable vulnerabilities could allow an attacker to read the communication between the affected device and a user, and compromise the availability of the targeted system. Thomas Meesters from cirosec GmbH and Ruhr University of Bochum, and Christian Siemers and Irakli Edjibia from Hochschule Augsburg reported these vulnerabilities to Siemens.
The following versions of LOGO!8 devices, used for basic small-scale automation tasks, suffer from the issues:
• SIEMENS LOGO!8: 6ED1052-xyyxx-0BA8 FS:01 to FS:06 / Firmware v1.80.xx and v1.81.xx
• SIEMENS LOGO!8: 6ED1052-xyy08-0BA0 FS:01 / Firmware version prior to v1.82.02
An attacker with network access to Port 10005/TCP of the LOGO!8 device could cause a denial-of-service condition by sending specially crafted packets. This security vulnerability could be exploited by an unauthenticated attacker with network access to the affected service. No user interaction is required, and successful exploitation could compromise the availability of the targeted system.
CVE-2019-6571 is the case number assigned to this vulnerability, which has a CVSS v3 base score of 7.5.
In addition, the integrated webserver does not invalidate the Session ID upon user logout. An attacker who successfully extracted a valid Session ID is able to use it even after the user logs out. This security vulnerability could be exploited by an attacker in a privileged network position who is able to read the communication between the affected device and the user, or by an attacker who is able to obtain valid Session IDs through other means. To facilitate this exploit, the user must first invoke a session to the affected device.
CVE-2019-6584 is the case number assigned to this vulnerability, which has a CVSS v3 base score of 7.5.
The product sees use mainly in the commercial facilities and transportation systems sectors. It also sees action on a global basis.
No known public exploits specifically target these vulnerabilities. High skill level is needed to exploit.
For Siemens LOGO!8: 6ED1052-xyyxx-0BA8 FS:01 to FS:06 / Firmware version v1.80.xx and v1.81.xx: Siemens recommends upgrading to a new version.
Click here for the product updates.
Siemens LOGO!8: 6ED1052-xyy08-0BA0 FS:01 / Firmware version prior to v1.82.02: Update to vV1.82.02 or higher.
Siemens has identified the following specific workarounds and mitigations users can apply to reduce the risk:
• Protect network access to the device.
• As a general security measure Siemens recommends protecting network access to the devices with appropriate mechanisms.
• In order to operate the devices in a protected IT environment, Siemens recommends configuring the environment according to Siemens’ operational guidelines for Industrial Security, and following the recommendations in the product manuals.
Click here for additional information on Industrial Security by Siemens.
For more information on these vulnerabilities and more detailed mitigation instructions, please see Siemens security advisory SSA-774850.