WAGO: Cloud Connectivity Remote Code Execution Vulnerability

WAGO Cloud Connectivity is prone to Remote Code Execution

VDE-2020-010 (2020-03-09 11:25 UTC+0200)

CVE Identifier

CVE-2019-5161

Affected Vendors

WAGO

Affected Products

Article Name Article Number Version
Series PFC100 750-81xx/xxx-xxx All FW versions
=> 12 are affected
Series PFC200 750-82xx/xxx-xxx
Touch Panel 600 Standard Line
type Visu- / Control Panel
762-4xxx
Touch Panel 600 Advanced Line
type Visu- / Control Panel
762-5xxx
Touch Panel 600 Marine Line
type Visu- / Control Panel
762-6xxx

Vulnerability Type

Reliance on File Name or Extension of External-Supplied File (CWE-646)

Summary

An attacker needs an authorized login with administrative privileges on the device in order to exploit the herein mentioned vulnerability.
The weakness allows an attacker which has admin privileges on the device to redirect to his own Azure cloud account and install malicious software with the firmware update functionality.

Impact

These vulnerabilities allow an attacker which has admin privileges, an Azure cloud account and also access to the device to redirect the cloud connection. With thus he is able to install any malicious software by manipulating the firmware update file.

An exploitable remote code execution vulnerability exists in the Cloud Connectivity functionality of affected WAGO products. A specially crafted XML file will direct the Cloud Connectivity service to download and execute a shell script with root privileges.

Solution

Use strong passwords for all user accounts, especially for administrative user accounts on the device.

Mitigation

  • Check the hashes of the Update packet, do not use update files which has a different hash then the original one
  • Follow the instructions in WAGOs handbook Cyber Security for Controller
  • Restrict network access to the device.
  • Do not directly connect the device to the internet
  • Use an encrypted VPN connection to the device
  • Disable unused TCP/UDP-ports

Reported by

These vulnerabilities were reported by Kelly Leuschner of Cisco Talos to WAGO. Coordination done by CERT@VDE.