Phishing is the fraudulent practice of sending messages, typically emails, that trick the recipient into doing something that they normally would not do, such as disclosing sensitive information or installing malware on their device. Phishers often include a link to a website that spoofs a well-known brand and victims are tricked into disclosing sensitive data or malicious files are attached to emails. Email security solutions are now much better at detecting malicious hyperlinks, and advanced email security solutions such as SpamTitan Plus can detect all known malware and have email sandboxing for behavioral analysis of suspicious emails to identify and block zero-day malware threats.

Cybercriminals Turn to Callback Phishing to Evade Cybersecurity Solutions

The first goal of a phishing attack is to get a message, be that an email, SMS, or instant message to an end user, and one of the ways that this is achieved is by sending emails with no malicious content – no hyperlinks or email attachments. Instead, the messages have a realistic call to action that requires immediate attention, and a phone number is provided in the email that the recipient must call to address the pressing problem that is outlined in the email. The phone line is manned by the threat actor who then talks the user through performing certain actions that provide remote access to their device.

Callback phishing typically involves an email warning the recipient about a charge for a product that is about to be taken, such as the expiry of a free trial or the end of a subscription term. The charge is excessive and the number provided in the email must be called to stop the charge. One such campaign that has recently been uncovered involves a fictitious charge for an antivirus subscription. In one of these attacks, the threat actor spoofs the antivirus software provider Norton. The email advises the recipient that the subscription period has come to an end and a charge for the next subscription period will be applied – $349.95. Naturally, such a high charge for a product would prompt many people to call the number to block it.

As with other callback phishing campaigns, the attacker tricks the recipient into downloading a program to their device that they are told is necessary to prevent the renewal of the subscription. The program gives the attacker remote access to the user’s device. Once access has been gained, the attacker can conduct a variety of nefarious activities.

Victim Transferred $34,000 to Attacker’s Account

In one of these scams, after access was gained to a victim’s device, the attacker transferred $34,000 from the user’s account. After providing the attacker with remote access to their laptop, the victim was instructed to perform other actions, one of which was entering their credentials into a phishing page. The victim was told that the payment for the antivirus software had already been taken, so a refund needed to be processed. The attacker then told the victim that an error had been made and a refund of $34,000 had been deposited in his account and immediate action was required to correct the error to avoid legal trouble.

The attacker remained on the phone while the victim called his bank, and while the victim was on the phone, the attacker transferred $34,000 from the victim’s Money Market account to his checking account. When the victim saw the $34,000 deposit, he assumed it to be the refund from Norton, and arranged the transfer to the bank account provided by the attacker. The attacker told the victim that in order not to arouse suspicion at the bank, he should inform the bank that the payment was for a vehicle. The victim was unable to see the malicious activity as the attacker had overlayed a blue screen on his laptop.

In this case, suspicions were raised and the funds were put into a suspense account at the recipient bank. U.S. Secret Service Special Agent Iris Joliff was able to obtain a seizure warrant from a judge allowing the money to be recovered; however, scams such as these are often only detected when the transferred funds have been withdrawn from the attacker-controlled account.

Improve Resilience to Callback Phishing with SafeTitan

Email security solutions may be effective at blocking malicious attachments and hyperlinks in emails, but they can rarely identify callback phishing scams as it is difficult to determine if a phone number is malicious. The most effective way that businesses can combat callback phishing is through security awareness training. Callback phishing should be covered in security awareness training sessions and also added to phishing simulation campaigns, to test whether the training has been understood and is being applied. SafeTitan from TitanHQ makes this easy, as callback phishing modules can easily be added to training courses and SafeTitan also includes a phishing simulator with phishing templates to test resilience to callback phishing and identify individuals who require further training in this area.

For further information on the SafeTitan platform and advice on how to further improve your defenses against phishing, give the TitanHQ team a call.