Email pranks and spoofing

Earlier today a twitter user calling himself Email Prankster released copies of email conversations with various members of the current US administration. Based on his twitter feed, and articles from BBC News and CNN, it appears that the prankster forged “friendly from” names in emails to staffers.
A bunch of folks will jump on this bandwagon and start making all sorts of claims about how this kind of thing would be prevented if the Whitehouse and other government offices would just implement DMARC. Problem is, that’s not true. It wouldn’t have helped at all in this case. Looking at the email screenshots all of the mail seems to come from legitimately registered addresses at free email providers like mail.com, gmail.com, and yandex.com.
One image indicates that some spam filter noticed there may be a problem. But apparently SUSPECTED_SPAM in the subject line wasn’t enough to make recipients think twice about checking the email.

The thing is, this is not “hacking” and this isn’t “spear phishing” and it’s not even really spoofing. It’s social engineering, at best. Maybe.


Modern mail clients make this kind of thing trivial. They often hide the email address from the user. Mobile mail clients are horrible about this. They often don’t even have the option to look at the actual email address. I regularly put clicking, opening or responding to an email on the back burner until I can get to my desk and see the full message. Often the message is fine. But sometimes it isn’t.
Email is a hostile channel. We, as users, need to treat it that way. I saw a discussion about this on Facebook earlier today. How can we, as the people who contribute to email standards, make it easier to identify spoofs like this? Well, as long as recipients are going to reply to arthur.schwartz@yandex.com or reince.priebus@mail.com as if they were from @whitehouse.gov we can’t. Even Eric Trump somewhat failed when he replied to “donaldtrumpjr.trump@gmail.com” asking if he really sent the email. (Don’t respond, create a new mail to the address you already have from him.)
This is just another example of how humans are the weakest link in any security scheme. Technology can help – maybe there should be a MUA tag that shows whether or not this is an email address (not name, email address) you’ve corresponded with before. But technology cannot save us from ourselves if we’re distracted or negligent.

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People are the weakest link

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DMARC doesn't fix Phishing

Not a new thing, but a nice example just popped up in my inbox on my phone.

 
But FedEx solved their entire phishing problem when they published a strict p=reject DMARC record, right?
This didn’t come from fedex.com. It came from another domain that looks vaguely like fedex.com – what that domain is doesn’t matter, as the domain it’s sent from isn’t displayed to the user on my phone mail client. Nor is it displayed to the user by Mail.app on my desktop, unless you turn off Mail → Preferences … → Viewing → Use Smart Addresses.

That lookalike domain could pass SPF, it could be used as d= in DKIM signing, it could even be set up with DMARC p=reject. And the mail is pixel identical to real mail from fedex.com.
On my desktop client I can hover over the link and notice it looks suspicious – but it’s no more suspicious looking than a typical ESP link-tracking URL. And on mobile I don’t even get to do that.
SPF and DKIM and DMARC can temporarily inconvenience phishers to the extent that they have to change the domain they’re sending from, but it’ll have no effect on the vulnerability of most of your audience to being phished using your brand.

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Phishing is an online threat that’s been around for more than 20 years. I initially heard of it in relation to spammers taking over an AOL account to send out spam. These days phis is more dangerous and more sophisticated. Phishing is not just used to send spam. It’s used to take over elections; it’s used to steal millions of dollars. Experts estimate that globally phishing costs companies over 9 billion dollars a year.
Even in the last two weeks we’ve seen 2 major phishing incidents. One targeted Google Docs, one targeted Docusign. Reading the news reports these are different than many of the more common phishing attacks and, to me, represent an evolution in standard phishing techniques.

The Google attack in early May was an evolution in getting access to a Google account. Instead of directing users to a fake Gmail login page, the phish asked users to allow “Google Docs” (actually an app controlled by the phisher) to access to their Google account.
I’m sure all of you have used an app or website that lets you login with Facebook or Gmail or Twitter. This is all done with a protocol called OAuth. OAuth is also how you give access to mailbox management tools like I discussed a few weeks ago.  Basically, OAuth lets users grant access and permission to a site or application using a second site without revealing their username and password. (It’s more complicated than I want to discuss, but if you’re looking for some information check out some of the sites I’ve found: wikipedia, Varonis blog, Digital Ocean knowledge base, or just search google for oauth.)
The switch from asking for a password to asking for access is, to my mind, a significant change. Now we have to be aware of what we’re authorizing and make sure that app isn’t malicious.
The Docusign phish is another evolution.  As I was looking at the phish I received yesterday I realized that it was sent to a tagged address. A tagged address only Docusign had. None of my other, heavily phished, addresses received the phish. None of Steve’s addresses received the phish. This wasn’t a widespread spray and pray phishing attack. The phishers targeted Docusign users. Yesterday afternoon, Docusign confirmed that someone stole user addresses.
This is a switch from just randomly looking for victims to targeting users of a specific service.
Phishing attacks look for the weakest links to gain access to computers, information, and money. The weakest links are always humans. Phishers have adapted to security measures for the last 20 years. There is zero reason that they won’t continue to adapt.
 
 
 

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