An issue was discovered on Enphase Envoy R3.x and D4.x devices. There is a custom PAM module for user authentication that circumvents traditional user authentication. This module uses a password derived from the MD5 hash of the username and serial number. The serial number can be retrieved by an unauthenticated user at /info.xml. Attempts to change the user password via passwd or other tools have no effect.

References

• https://nvd.nist.gov/vuln/detail/CVE-2020-25754
• https://enphase.com/en-us/products-and-services/envoy-and-combiner
• https://medium.com/stage-2-security/can-solar-controllers-be-used-to-generate-fake-clean-energy-credits-4a7322e7661a
• https://stage2sec.com