Spear Phishing is an email targeted at a specific individual or department within an organization that appears to be from a trusted source. It's actually cybercriminals attempting to steal confidential information.
A whopping 91% of cyberattacks and the resulting data breach begin with a “spear phishing” email, according to research from security software firm Trend Micro. This conclusively shows that end-users really are the weak link in IT security.
You may be wondering what it takes to send this type of attack. This is not trivial, and can only be done by someone trained in advanced hacking techniques. We will first take a look at the steps required to send an attack, and then we’ll look at steps to mitigate this threat. For the (simplified) attack steps I am freely borrowing from a great blog post by Brandon McCann, a well-known pentester.
I will try to keep this as non-technical as possible, but there will be a few terms you may have to look up. Here are the steps to begin with. We will go into all of these one by one and explain what they mean.
There are two ways you can send phishing campaigns: the first is ‘spray-and-pray’ which is a shotgun approach. Get as many email addresses from the organization you can, and send them all an email that they might click on. The second approach is decide what data you are after, then figure out who has access to that data, and specifically target those people. That is the spear phishing approach, and for instance LinkedIn is extremely useful during this targeting step.
There are several ways to get your hands on the email addresses from an organization. The one favored by the bad guys is using scripts to harvest email addresses from the large search engines. You’d be surprised how many emails you can get your hands on and how big your phishing attack surface is. KnowBe4 has a free service called the Email Exposure Check that provides your list of exposed email addresses as a one-time free service. Once you have the email addresses of the few people you are targeting you are ready for step two.
It’s obvious that if you want to arrive in the inbox of your target, you need to make sure that your email is not caught by the antivirus software that your target uses. Do your homework and research the IT job sites for open system admin positions at your target. The amount of information you find there is often astounding and tells you exactly what antivirus and which version they use. Otherwise social media provides many other ways to find out, and once you know, set up a test bed, install that AV and make sure the email comes through OK. You can use Metasploit to help you with this, it is an open source computer security project which provides information about security vulnerabilities and aids in penetration testing.
You need to make sure that you can get the information out of the organization you are attacking, so the payload you are sending with your attack needs to allow traffic to exit the organization. A popular payload is called ‘reverse_https’ because it creates an encrypted tunnel back to the metasploit server, which makes it very hard for security software like intrusion detection or firewalls to detect anything. For those products your exiting phishing data all looks like normal https traffic.
There are many articles written about this by now, and it’s the essence of social engineering end-users. If they haven’t had high-quality security awareness training they are easy targets for spear phishers. The attacker does research on their targets, find out who they regularly communicate with, and sends a personalized email to the target that uses one or more of the 22 Social Engineering Red Flags to make the target click on a link or open an attachment. Just imagine you get an email from the email address of your significant other that has in the subject line: Honey, I had a little accident with the car, and in the body: I made some pictures with my smart phone, do you think this is going to be very expensive?”
You can raise a temporary mail server and blast away, but that mail server will not have a reputation score which will block a lot of email from getting in. A better solution is going to GoDaddy, purchase a valid domain name, use the free email server that comes with the domain and set it up, so that you automatically have an MX record created for you by GoDaddy. While you are at it, also do a Whois lookup and change the GoDaddy Whois information for your phishing domain. All that helps mail getting through, which you can send with any email client, or with a script.
Let’s assume that your target clicked on the link, and you were able to place a keylogger on their machine. Now it’s a matter of waiting for the hourly burst of keyboard data back to your server, and monitoring for the credentials you are after. Once you have those, it’s a matter of getting into the workstation, get all network password hashes, crack them and get elevated to administrator access to the whole network.
Now, how to mitigate against attacks like this? First of all, you need all your defense-in-depth layers in place. Defending against attacks like this is a multi-layer approach. Make sure you have in place the following: an Email Gateway Spam Filter and/or a spam filter in your Exchange Server. Turn on the Outlook ‘Junk Email’ Filter, run different antivirus products on the workstation and the mailserver, have an active Intrusion Prevention Systems, use Web Proxy Servers, and ideally have deep-packet inspection Egress filtering, plus there are some more things you could add. The trick is to make it as hard as possible for the attacker to get through.
And now let’s look at some other tactics that will help prevent a successful attack: