Encrypted Email Has a Major, Divisive Flaw

Posted on Monday May 14, 2018  |  security

An anonymous reader quotes a report from Wired: The ubiquitous email encryption schemes PGP and S/MIME are vulnerable to attack, according to a group of German and Belgian researchers who posted their findings on Monday. The weakness could allow a hacker to expose plaintext versions of encrypted messages -- a nightmare scenario for users who rely on encrypted email to protect their privacy, security, and safety. The weakness, dubbed eFail, emerges when an attacker who has already managed to intercept your encrypted emails manipulates how the message will process its HTML elements, like images and multimedia styling. When the recipient gets the altered message and their email client -- like Outlook or Apple Mail -- decrypts it, the email program will also load the external multimedia components through the maliciously altered channel, allowing the attacker to grab the plaintext of the message. The eFail attack requires hackers to have a high level of access in the first place that, in itself, is difficult to achieve. They need to already be able to intercept encrypted messages, before they begin waylaying messages to alter them. PGP is a classic end-to-end encryption scheme that has been a go-to for secure consumer email since the late 1990s because of the free, open-source standard known as OpenPGP. But the whole point of doing the extra work to keep data encrypted from the time it leaves the sender to the time it displays for the receiver is to reduce the risk of access attacks -- even if someone can tap into your encrypted messages, the data will still be unreadable. eFail is an example of these secondary protections failing.