An issue was discovered in Proofpoint Email Protection through 2019-09-08. By collecting scores from Proofpoint email headers, it is possible to build a copy-cat Machine Learning Classification model and extract insights from this model. The insights gathered allow an attacker to craft emails that receive preferable scores, with a goal of delivering malicious emails.
CWE-697 - Incorrect Comparison
The software compares two entities in a security-relevant context, but the comparison is incorrect, which may lead to resultant weaknesses.