CVE-2020-6959

The following versions of MAXPRO VMS and NVR, MAXPRO VMS:HNMSWVMS prior to Version VMS560 Build 595 T2-Patch, HNMSWVMSLT prior to Version VMS560 Build 595 T2-Patch, MAXPRO NVR: MAXPRO NVR XE prior to Version NVR 5.6 Build 595 T2-Patch, MAXPRO NVR SE prior to Version NVR 5.6 Build 595 T2-Patch, MAXPRO NVR PE prior to Version NVR 5.6 Build 595 T2-Patch, and MPNVRSWXX prior to Version NVR 5.6 Build 595 T2-Patch are vulnerable to an unsafe deserialization of untrusted data. An attacker may be able to remotely modify deserialized data without authentication using a specially crafted web request, resulting in remote code execution.

Weakness

The product deserializes untrusted data without sufficiently ensuring that the resulting data will be valid.

Affected Software

Potential Mitigations

• Make fields transient to protect them from deserialization.
• An attempt to serialize and then deserialize a class containing transient fields will result in NULLs where the transient data should be. This is an excellent way to prevent time, environment-based, or sensitive variables from being carried over and used improperly.

Related Attack Patterns

• https://cwe.mitre.org/data/definitions/586.html

References

• https://www.us-cert.gov/ics/advisories/icsa-20-021-01
• https://www.us-cert.gov/ics/advisories/icsa-20-021-01