Improper Input Validation vulnerability in PHOENIX CONTACT FL/TC MGUARD Family in multiple versions may allow UDP packets to bypass the filter rules and access the solely connected device behind the MGUARD which can be used for flooding attacks.

A remote, unauthenticated attacker could cause a denial-of-service of PHOENIX CONTACT FL MGUARD and TC MGUARD devices below version 8.9.0 by sending a larger number of unauthenticated HTTPS connections originating from different source IP’s. Configuring firewall limits for incoming connections cannot prevent the issue.

An Improper Validation of Integrity Check Value issue was discovered in PHOENIX CONTACT mGuard firmware versions 7.2 to 8.6.0. mGuard devices rely on internal checksums for verification of the internal integrity of the update packages. Verification may not always be performed correctly, allowing an attacker to modify firmware update packages.