Email Security Intelligence - Think Like A Criminal: How To Write A Phishing Email

With an alarming 65 percent increase in phishing attempts this past year, chances are you’ve been targeted in a phishing campaign. Hopefully you recognized signs of fraud and quickly deleted the malicious email; however, if you did get fooled, you’re not alone. Seventy-six percent of businesses fell victim to a phishing attack in 2019.

To defend against this dangerous and highly prevalent exploit, it helps to view phishing from the eyes of an attacker. In this article, we will teach you how to think like a criminal to gain a deeper understanding of phishing and email account compromise (EAC) - but only for educational purposes!

What Is Phishing and How Does It Work?

Phishing is an email-borne attack that involves fraudulent communications which appear to come from a reputable source. The goal of a phishing campaign is either to steal sensitive credentials or to install malware on the victim’s machine. When a user clicks on a malicious link within a phishing email, he or she is usually directed to a phony website login page. When the unsuspecting user logs in to this fraudulent page, his or her credentials are harvested by the attacker and can be used to compromise email accounts, obtain sensitive financial information or steal money. If a victim downloads a malicious attachment included in a phishing email, his or her computer can be infected with destructive malware. 

Cyber criminals employ advanced social engineering techniques to manipulate psychology - encouraging recipients to act rapidly without stopping to think. Successful scams leverage trust - from the use of a familiar email address, to a familiar message in the body of the email, to the inclusion of a normal signature.

Recent phishing scams are exploiting email users’ heightened anxiety surrounding COVID-19, utilizing tactics such as impersonating government agencies, advertising fraudulent test kits and asking for donations. One notorious COVID-related phishing campaign claims to provide a list of “local active COVID-19 infections”. It includes the logo of the Center for Disease Control Health Alert Newark. When recipients click on a link within the email, they are asked to enter their email login credentials - which then end up in the hands of the attackers and can be used in account takeovers and dangerous future attacks. 

How To Write A Phishing Email

Now it’s time to get cynical and think like a phisher! To demonstrate how to craft a phishing campaign, I will be using a phishing email recently identified and quarantined by Guardian Digital EnGarde Cloud Email Security. 

 

1. Compromise an email account that can be used to launch a phishing campaign.

In a phishing campaign, fraudulent emails are either sent from an account that has been compromised in a previous attack carried out using another compromised account or from a spoofed email address that the attacker creates. This one really hits close to home, as the above email came from a Berkshire Hathaway employee’s compromised local desktop Outlook account (vtaig.com is actually Berkshire Hathaway Automotive). Even the identity of the user’s Outlook email signature was kept to leverage the trust that occurs with an existing profile.

Whereas phishing emails sent from spoofed email addresses which often contain misspelled words or additional characters can be relatively easy to identify as fraud, malicious emails like this one are highly deceptive and often go undetected because they are sent from a legitimate email account that has been hijacked by an attacker. This particular email passed through a Message Labs (now Symantec.cloud) antispam system undetected. 

Received: from [100.112.1.169] (using TLSv1.2 with cipher
DHE-RSA-AES256-GCM-SHA384 (256 bits))
by server-3.bemta.az-b.us-east-1.aws.symcld.net id
27/82-39809-D39E3CE5; Tue, 19 May 2020 14:12:13 +0000
Received: from ptr1.vtaig.com (HELO mail.vtaig.com) (152.194.33.140)
by server-3.tower-381.messagelabs.com with ECDHE-RSA-AES256-SHA384
encrypted SMTP; 19 May 2020 14:12:10 -0000

Identifying and blocking sophisticated phishing attempts that originate from compromised email accounts requires superior protection than traditional antispam software provides. To safeguard the inbox against these dangerous attacks which can result in steep financial loss, significant downtime and reputation damage, it is critical that businesses implement an advanced cloud email security solution comprised of multiple layers of detection engines and spam filtration technology. Combating phishing requires a solution that is capable of learning and updating in real-time to remain ahead of emerging exploits.

 

2. Convince the recipient to give up credentials. 

Phishing emails often contain malicious links or attachments designed to either harvest victims’ credentials or download malware on a victim’s device. This particular phishing email contains a malicious PDF attachment that requires the victim to login to a fake Microsoft SharePoint account where the attacker would then have access to the login credentials of the Berkshire Hathaway employee targeted in this attack.

It can be very difficult to discern whether an embedded link or attachment is legitimate or fraudulent, and one mistake can have devastating consequences - shaking a company to its core. To protect against email attacks involving malicious attachments or links, organizations should implement a solution that offers complete defense against ALL malicious links and attachments with real-time URL scanning and broad-type file analysis.

 

3. Evade spam filters with the use of nonspecific language.

Phishers typically use vague, nonspecific language in their campaigns. In this particular case, both the subject and the body text of the email are general - conveying a cold, unfriendly tone. As opposed to including details on the contract payment, the attacker simply chose to use “Doc” as the  subject. Instead of including the recipient’s name in the greeting, the phisher initiates this email with a simple “Fyi”. 

In their scams, threat actors often avoid using words such as “IRS” that are commonly picked up by spam filters in an effort to remain undetected for as long as possible. Regardless of this tricky tactic, a comprehensive, multi-layered email security solution will identify and quarantine these dangerous emails, preventing the serious harm that can result from a phishing attempt reaching the inbox. 

 

4. Compromise other email accounts, which can be used to launch future attacks.

If you carefully examined the above image, you may have picked up on the fact that this email does not contain the recipient’s email address. This is related to how criminals launch their attacks. Phishers either run through the address book of the compromised email account they are sending messages from, or define a list of victims that they plan to target. In many cases, phishers will “trickle” out these malicious emails slowly in an effort to fly under the radar for as long as possible. 

Phishing is a vicious cycle: successful attempts result in the compromise of other accounts which can be used to launch future phishing attacks, compromising yet more email accounts. Breaking this cycle and winning the fight against cyber crime requires protection that is able to rapidly and accurately detect phishing and impersonation attacks, preventing EAC and the perpetuation of phishing campaigns.

 

Interested in learning more about how you can safeguard your business, your data and your users from phishing attacks? We can help! Speak with a security representative today.