Phishing detection techniques for predicting a password for decrypting an attachment for the purpose of malicious content detection are described herein. According to one embodiment, in response to a communication message, as such an electronic mail (email) message having an encrypted attachment, content of the communication message is parsed to predict a password based on a pattern of the content. The encrypted attachment is then decrypted using the predicted password to generate a decrypted attachment. Thereafter, a malicious content analysis is performed on the decrypted attachment to determine a likelihood as to whether the decrypted attachment contains malicious content.