After the Target Credit Card breach this past week affecting over 100,000,000 people, consumers have been on edge about access to personal data. Then this week, reports began to surface about an email that claimed to be from the CEO of Target offering credit card monitoring services:
On the surface, the email displayed all the classic signs of a phishing email:
The “from” address was from a suspicious domain, bfi0.com
The Target logo is not properly displayed
The email offers free credit monitoring services, which is a classic phishing scam
Social media sources began throwing red flags signaling that the email may have been fraudulent:
Target spox says the bfi0(dot)com emails are legit. Why use that domain for a sensitive issue? “We are sending tens of millions of emails”
— Geoffrey Fowler (@geoffreyfowler) January 17, 2014
Was this email spam, though?
If the email was spam, the first thing to investigate is how millions of copies made it past spam filters. For that, we look at two pieces of information – DKIM and SPF records. DKIM uses cryptography to “prove” who the sender was, and SPF is a tag on websites that show who is allowed to send email from that domain.
For the Target email, I looked at the headers and GMail validated both DKIM and SPF for the domain. This meant that bfi0.com sent the email – the “From” address was not being faked. The DKIM and SPF validation also meant that it helped the credibility of the email as it passed through spam filters.
Received-SPF: pass (google.com: domain of firstname.lastname@example.org designates 220.127.116.11 as permitted sender) client-ip=18.104.22.168;
Authentication-Results: mx.google.com; spf=pass (google.com: domain of email@example.com designates 22.214.171.124 as permitted sender) firstname.lastname@example.org; dkim=pass email@example.com Return-Path: <firstname.lastname@example.org> DKIM-Signature: v=1; a=rsa-sha1; d=target.bfi0.com; s=ei; c=simple/simple; q=dns/txt; email@example.com; t=1389913363; h=From:Subject:Date:To:MIME-Version:Content-Type; bh=0Tw0KwI1VkkrQDwTITKqSCMS6YA=; b=FerspETyfmnYlcbO+Noxgge27afmUdcuFZ9bdu4gyCueCtCWEWUOvFfWgW5ePrRm XyJNZy37Mz3YYkAIVYpnL6e2ddvzXvtxCdQduRM0B3PWJa6aWX9u2Uaw+DKietIH 8l7gdyBl+IVlaxCimKVkwRpw/bX1jRjjCvh/1H1Vupk=; DomainKey-Signature: q=dns; a=rsa-sha1; c=nofws; s=ei; d=target.bfi0.com;
Now that the Target email can be definitely traced to bfi0.com, we investigate the server to see if it is suspicious. At first glance, visiting the domain gives a blank page – suspicious. However, upon deeper inspection, the domain WhoIs data reveals that it is owned by Epsilon.com – a division of Alliance Data, a $12 Billion publicly-traded marketing services company.
Security Graph Inspection
The OpenDNS Security Graph shows that bfi0.com is a high-traffic domain – it receives about a quarter as many DNS queries per hour as Target.com. Furthermore, initial algorithmic analysis shows that the domain is benign.
Analyzing the IP address behind the domain provides the most telling information about the Target email. The IP address behind bfi0.com hosts over 100 known domains. Some of these are subdomains of well-established websites, including:
These domains include reputable banks and Fortune 100 companies. The last two domains on the list link the Target corporate website to the server sending emails for bfi0.com.
Phishing or Official?
The conclusion: Official
Based on OpenDNS Security Graph research and DKIM, we can both verify that this email came from the IP address 126.96.36.199 behind bhi0.com, and we can confirm that this server also powers email.target.com.
Why did the email come from such an obscure domain? It appears that bfi0.com is the default sending address for an email service used by dozens of Fortune 100 companies. In this case, it appears that Target failed to configure the “from” address to match their domain, email.target.com.