" opportunistic TLS Archives - HIPAA News, Web & Email Security Tips & News - Plus More | LuxSci
LuxSci

Posts Tagged ‘opportunistic TLS’

SMTP TLS: All About Secure Email Delivery over TLS

Monday, October 2nd, 2017

TLS stands for “Transport Layer Security” and is the successor of “SSL” (Secure Socket Layer). TLS is one of the standard ways that computers on the Internet transmit information over an encrypted channel. In general, when one computer connects to another computer and uses TLS, the following happens:

  1. Computer A connects to Computer B (no security)
  2. Computer B says “Hello” (no security)
  3. Computer A says “Lets talk securely over TLS” (no security)
  4. Computer A and B agree on how to do this (secure)
  5. The rest of the conversation is encrypted (secure)

In particular:

  • The meat of the conversation is encrypted
  • Computer A can verify the identity of Computer B (by examining its SSL certificate, which is required for this dialog)
  • The conversation cannot be eavesdropped upon (without Computer A knowing)
  • The conversation cannot be modified by a third party
  • Other information cannot be injected into the conversation by third parties.

Basic email security starts with SMTP TLS

TLS (and SSL) is used for many different reasons on the Internet and helps make the Internet a more secure place, when used. One of the popular uses of TLS is with SMTP for transmitting email messages between servers in a secure manner.  See also:

Read the rest of this post »

Does TLS Corruption Spell the end of SMTP TLS?

Tuesday, November 3rd, 2015

We have seen discussions recently about how attackers can interfere with SMTP TLS, influencing connections, and causing them to be downgraded to insecure — SMTP without TLS.  E.g. Ars Technica’s – “Don’t Count on STARTTLS to Automatically Encrypt your Sensitive Emails“.

What is being discussed here is a very real attack on Opportunistic TLS. I.e. the kind of automated establishment of encryption that can happen when two email servers being their dialog and discover that “hey, great, we both support TLS so lets use it!”  In such cases, servers take the “opportunity” to use TLS to encrypt the delivery of an email message from one server to another.  Opportunistic TLS is great as it is enabling automatic encryption of more and more email over time (see: Who supports TLS?).

The problem is that the initial negotiation of the SMTP email connection, before TLS is established, occurs over an insecure channel.  A man-in-the-middle attacker can interfere with this connection so that it appears that TLS (i.e. the STARTTLS command) is not supported by the server (when it really is).  As a result, the sending server will never try to use TLS and the connection will remain insecure — transmitting the email message “in the clear” and ripe for eavesdropping.

Read the rest of this post »

The Case For Email Security

Tuesday, March 31st, 2015

Section 1: Introduction to Email Security

You may already know that email is insecure; however, it may surprise you to learn just how insecure it really is. For example, did you know that messages which you thought were deleted years ago may be sitting on servers half-way around the world? Or that your messages can be read and modified in transit, even before they reach their destination? Or even that the username and password that you use to login to your email servers can be stolen and used by hackers?

This article is designed to teach you about how email really works, what the real security issues are, what solutions exist, and how you can avoid security risks.

Information security and integrity are centrally important  as we use email for personal and business communication: sending confidential and sensitive information over this medium every day. While you are reading this article, imagine how these security problems could affect your business or personal life and your identity…. if they have not already.

Read the rest of this post »

Secure TLS Email for Bank of America Partners

Wednesday, August 28th, 2013

Bank Of America LogoSeveral years back, we discussed Enforcing Email Security with TLS when Communicating with Banks. This is a critical stipulation for many banks that have strict requirements that all email messages be encrypted in transit via TLS when communicating with them.

Bank of America

Bank of America (BoA) is a case in point.  Their requirements are as follows:

Read the rest of this post »