Email surveillance

There’s a new article in the SF Chronicle that says the University of California, Office of the President (UCOP) has been monitoring emails going in and out of the UC system by using computer hardware. I wanted to give my personal opinion, as a computer programmer and somebody who has experience managing mail exchangers1. The quotes in the SF Cron article are very generous with technical details about the email surveillance system. Most of the time, articles about mass surveillance are dumbed down, but this one gives us at least a little something to chew on.

Email was not originally designed to be a secure protocol. Over the three (four?) decades that email systems have been used, computer people have created several extensions to the original SMTP2 and 822 envelope protocol to provide enough modern security to make email “good enough” for modern use. Most email today is exchanged under the protection of STARTTLS, which is an extension for SMTP that upgrades a cleartext connection to an encrypted connection, if both parties support it. The goal of STARTTLS is to provide resistance against passive monitoring. It doesn’t provide any guarantees about the authenticity of the other party, because usually the certificates aren’t validated, so STARTTLS is still vulnerable against MITM attacks3. There are other email-security extensions. But they’re either designed for ensuring authenticity rather than privacy (like SPF, DKIM, and DMARC) or they’re not widely used (like GPG).

The only protection we have against passive snooping of emails is STARTTLS. According to the SF Cron article, the “intrusive device” installed at UC campuses is intended to capture and analyze traffic, rather than intercepting and modifying it. So, I took a look at some of the emails I’ve received at my personal address over the last 3.5 years of living in Berkeley. I looked specifically at the advertising emails I get from, because I’ve been receiving them consistently for many years, and they always come from the same place (Amazon SES). All of my most recent emails from Amazon follow this path, according to the email headers:

  • Amazon SES
  • UC Berkeley Mail Server “ees-ppmaster-prod-01”
  • 3 local mail filters, called “pps.reinject”, “pps.reinject”, and “pps.filterd”
  • UC Berkeley Mail Server “ees-sentrion-ucb3”
  • Google Apps Mail Server

Before April 2015, another UC Berkeley Mail Server was part of this path, in between the “sentrion” server and the Google Apps server. Before December 2014, the path looked completely different. There was only a single server between SES and Google, which was labeled “”.

According to the email headers, each step along the path is encrypted using STARTTLS, except for some of the local mail filters. Those 3 local mail filters are programs that run on the UC Berkeley Mail Server which might do things like scanning for viruses or filtering spam. They don’t exactly need encryption, because they don’t communicate over the network. I also noticed that before May 2015, there was only 1 local mail filter (the “pps.filterd” one) instead of 3.

The SF Cron article mentions that email surveillance started after attacks on UCLA Medical Center, which occurred in July 2015. Unfortunately, nothing significant seems to have changed in the email headers between June and October of 2015. But the use of STARTTLS, even within UC Berkeley’s own networks, casts doubt on the idea that UCOP surveillance was implemented as passive network monitoring.

If the surveillance was implemented at the network level, it would have to proxy the SMTP connections between all of the “ppmaster” and “sentrion” servers, as well as spoof the source IP or routing tables or reverse DNS lookup tables of the entirety of Berkeley’s local email network. It’d be an unnecessarily sophisticated method, if they just wanted to hide the presence of surveillance hardware.

On the other hand, if surveillance was implemented with the cooperation of campus IT staff, it would be pretty simple to implement for all emails campus-wide. There are already plenty of unlabeled local mail filters in place. These could easily be configured to forward an unencrypted copy of all emails to a 3rd party vendor’s system, for monitoring and analysis. Additionally, “sentrion”, which probably refers to SendMail’s Sentrion product, looks like it was expressly designed for the purpose of recording and analyzing large amounts of email.

There are a couple of problems if email monitoring really were implemented on the mail servers themselves with the cooperation of campus IT staff. If this is really the case, then it would require another system to monitor web traffic, which doesn’t seem to be explained in the article. Or perhaps, the claim that web traffic were being monitored is incorrect4.

I’ve always accepted that work email should be considered the property of your employer. Your personal stuff should stay on your personal cell phone and email accounts. However, students are not employees of the University5. I don’t know much about law, but I feel like FERPA was passed to address these kinds of privacy questions regarding students and academic institutions. Implementing mass email surveillance without consulting faculty and students, regardless of its legality, seems underhanded and embarrassing for what claims to be the number one public university in the world.

  1. I’m currently a student and (technically?) an employee of UC Berkeley. But these opinions are my own.
  2. The Simple Mail Transfer Protocol, which is used to deliver all publicly-routed email.
  3. Man-in-the-middle attacks
  4. Most web traffic (including RogerHub) goes through HTTPS today anyway. Monitoring web traffic without a MITM proxy would be ineffective.
  5. Unless you happen to be both.

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Wed Jan 18 2017 09:58:35 +0000