CVE-2018-5441

Vulnerability

An improper validation of integrity check value vulnerability exists in PHOENIX CONTACT mGuard firmware versions 7.2 through 8.6.0. The devices rely on internal checksums to verify the integrity of firmware update packages, but the verification may not always be performed correctly, allowing an attacker to modify update packages [1].

Exploitation

An attacker needs low skill level to exploit this vulnerability [1]. The attacker can modify firmware update packages, likely requiring the ability to intercept or replace update files during distribution (e.g., man-in-the-middle on the network or compromise of the update server). No authentication or user interaction is explicitly required, though the attacker must have network access to the update delivery path [1].

Impact

Successful exploitation allows an attacker to modify firmware update packages, which could lead to arbitrary code execution on affected mGuard devices. This compromises the confidentiality, integrity, and availability of the device and its network functions [1].

Mitigation

PHOENIX CONTACT recommends upgrading to firmware version 8.6.1 [1]. Customers can obtain the fixed firmware from product-specific download portals linked in the advisory [1]. No workarounds are mentioned; upgrading is the only mitigation.