In a test, CNET was able to intercept and read
Yahoo instant messages because the company has still not turned on
encryption. It's been at least 10 years since the security vulnerability
became public.
(Credit:
Declan McCullagh/CNET)
Nine months after Edward Snowden revealed
extreme Internet surveillance
by US and British intelligence agencies, some major technology
companies have yet to take rudimentary steps to shield their users'
instant messages from eavesdropping.
A CNET analysis shows that Yahoo and ICQ transmit the content of
supposedly private instant messages in unencrypted form, exposing them
to both government spies and
malicious snoops on the same Wi-Fi network. AOL's AIM service encrypts content -- but leaks metadata about who's talking to whom.
These privacy problems were highlighted by a Guardian
article
Thursday, which revealed that spy agencies were eavesdropping on
Yahoo's unencrypted video chats. A surveillance system code-named Optic
Nerve "intercepted and stored the webcam images of millions of Internet
users not suspected of wrongdoing," the paper said, citing documents
provided by Snowden.
That was possible because Yahoo has lagged far behind rivals Google and
Microsoft in adopting a standard technique known as SSL that scrambles
information before it's transmitted. SSL and similar technologies, if
implemented properly, are designed to be proof against even the NSA's
aggressive attempts to vacuum up petabytes of Internet traffic.
"We have ample evidence now that Yahoo doesn't really care about
security or the confidentiality of its customers' communications," said
Chris Soghoian,
principal technologist at the ACLU's Speech, Privacy and Technology
Project. "Whether it's the lack of encryption in Webmail, or the video
issue, Yahoo has ignored repeated warnings from researchers, from human
rights activists."
Yahoo users' vulnerability to snoops has been public knowledge for at least a decade. A 2004 article (
PDF) in
Hakin9 magazine
described how to intercept Yahoo messages using the tcpdump utility.
"There is no encryption, not even scrambling of the packets content,"
Hakin9 concluded.
Four years later, CNET contacted Yahoo as part of a
privacy survey
we conducted of companies providing instant messaging services. Yahoo
told us that it uses SSL only to scramble the user's password during the
initial authentication, and acknowledged that "Yahoo Messenger does not
use encryption for message delivery."
It took Snowden's revelations to spur the company's chief executive,
Marissa Mayer, into sealing this gaping security hole. In a blog post
last November,
nearly half a year after the spy agency files began to leak, Mayer said
that Yahoo will "offer users an option to encrypt all data flow to/from
Yahoo by the end of Q1 2014." She stopped short of pledging that
encryption would be turned on by default, however, a practice that
Google's chat system and Skype have followed for over half a decade.
Yahoo has been equally sluggish in adopting encryption for Web e-mail: It finally
activated HTTPS encryption for Yahoo Mail by default last month. By contrast, Google
enabled HTTPS by default for Gmail in 2010,
followed soon after by Hotmail. Facebook
enabled encryption by default in 2012.
A Yahoo spokesman yesterday provided CNET with a statement saying: "We
are committed to preserving our users' trust and security and continue
our efforts to expand encryption across all of our services."
"The only reason they're encrypting e-mail with Webmail now was a
front-page story in The Washington Post," said the ACLU's Soghoian. "It
was only then, in response to that coverage, that Yahoo turned on SSL by
default." That October 2013
article
revealed the NSA's Special Source Operations branch collected more
e-mail address books from Yahoo than from all other e-mail providers
combined. (Gmail addresses were exposed because of Apple's lack of
encryption in its Address Book app, a security oversight that Cupertino
subsequently fixed.)
Even today, after Yahoo turned on encryption by default for Web-based
e-mail (but not instant messaging), it's using older protocols with some
known security vulnerabilities. Yahoo's servers also don't support
forward secrecy, which would offer an extra layer of protection against government eavesdropping.
Google and
Twitter do.
ICQ messages were also unencrypted, as you can
see in the above screen capture from the Wireshark packet analyzer.
AOL's AIM client leaked metadata about who's talking to whom.
(Credit:
Declan McCullagh/CNET)
How we conducted the tests
We tested whether encryption was used in five messaging clients: AOL's
AIM, Apple's Messages app connecting to AIM, Google Hangouts, Mail.ru's
ICQ, Microsoft's Skype, and Yahoo Messenger. Mail.ru, an Internet
company in Russia, where ICQ remains
quite popular,
bought the service from AOL in 2010.
To perform the test, we used the Wireshark packet analyzer to intercept the communications flowing between a MacBook with
OS X 10.9.1 and the remote servers that each service used.
Neither ICQ nor the Yahoo Messenger Protocol encrypted the content of
the communications. That meant that when we sent a message, it was
transmitted across the Internet in the clear.
AOL's AIM desktop app made unencrypted connections to api.aim.net that
transmitted unique "to" and "from" identifiers. Even if the NSA and GCHQ
can't decrypt the content, the unencrypted unique identifiers could add
to the agencies' vast trove of metadata charting the
social connections of US and other citizens.
AOL and Mail.ru did not respond to requests for comment.
Google Hangouts, Skype, and Messages, on the other hand, used SSL
encryption consistently. This is what we expected -- it's been
reported
previously, and Skype encryption has been studied
in some detail -- and our tests confirmed it.
We acknowledge limitations to this test. We didn't evaluate the quality
of the SSL cipher suite or its implementation. Nor did we test for
certificate exploits. And we didn't test all clients; it's possible that
the Windows client for AIM, for instance, behaves differently. (The
protocol
used by AIM supports unencrypted chats, so if you use a third-party
client like Adium, be sure your privacy preferences under user accounts
are set to enable encryption.)
We also didn't test mobile apps, though previous reports have pointed to some problems. A 2012
paper (PDF)
presented at the Network and Distributed System Security Symposium said
that Voypi, an iPhone messaging app, fails to use encryption.
Thijs Alkemade, a computer science student and lead developer for the Adium instant messaging application,
posted a Python script last fall to intercept WhatsApp messages. He
warned users of WhatsApp, which Facebook subsequently bought for $16 billion:
You should assume that anyone who is able to eavesdrop
on your WhatsApp connection is capable of decrypting your messages,
given enough effort. You should consider all your previous WhatsApp
conversations compromised. There is nothing a WhatsApp user can do about
this but except to stop using it until the developers can update it.
An
analysis
of WhatsApp last week by information security firm Praetorian found
encryption flaws, the company said, that "the NSA would love." WhatsApp
has said it's fixing them.