Incorrect signature verification in django-ses

Vulnerability Description

Django-SES is a drop-in mail backend for Django. The django_ses library implements a mail backend for Django using AWS Simple Email Service. The library exports the `SESEventWebhookView class` intended to receive signed requests from AWS to handle email bounces, subscriptions, etc. These requests are signed by AWS and are verified by django_ses, however the verification of this signature was found to be flawed as it allowed users to specify arbitrary public certificates. This issue was patched in version 3.5.0.

References

• https://github.com/django-ses/django-ses/security/advisories/GHSA-qg36-9jxh-fj25
• https://github.com/django-ses/django-ses/commit/b71b5f413293a13997b6e6314086cb9c22629795
• https://github.com/django-ses/django-ses/blob/3d627067935876487f9938310d5e1fbb249a7778/CVE/001-cert-url-signature-verification.md