Luna Moth Phishing Extortion Campaign Targets Businesses in Multiple Sectors

A callback phishing extortion campaign by Luna Moth (aka Silent Ransom Group) has targeted businesses in multiple sectors, including legal and retail.

The findings come from Palo Alto Network’s security team Unit 42, which described the campaign in a new advisory published earlier today.

“This campaign leverages extortion without encryption, has cost victims hundreds of thousands of dollars and is expanding in scope,” reads the technical write-up.

At the same time, Unit 42 said that this type of social engineering attack leaves very few artifacts because it relies on legitimate technology tools to carry out attacks.

In fact, callback phishing, also known as telephone-oriented attack delivery (TOAD), is a social engineering method that requires a threat actor to interact with the victim to accomplish their goals.

“This attack style is more resource intensive but less complex than script-based attacks, and it tends to have a much higher success rate,” reads the advisory.

According to Unit 42, threat actors associated with the Conti group have extensively used this attack style in BazarCall campaigns.

“Early iterations of this attack focused on tricking the victim into downloading the BazarLoader malware using documents with malicious macros,” explained the researchers.

As for the new campaign, which Segnia security researchers first unveiled in July, it removes the malware portion of the attack.

“In this campaign, attackers use legitimate and trusted systems management tools to interact directly with a victim’s computer to manually exfiltrate data […] As these tools are not malicious, they’re not likely to be flagged by traditional antivirus products,” Unit 42 wrote.

The researchers also said that they expect callback phishing attacks to increase in popularity because of low per-target cost, low risk of detection and fast monetization factors.

“Common observables suggest a pervasive multi-month campaign that is actively evolving. Therefore, organizations in currently targeted industries, such as legal and retail, should be particularly vigilant to avoid becoming victims.”

Unit 42 added firms should consider reinforcing cybersecurity awareness training programs with a focus on unexpected invoices, as well as requests to initiate a phone call or to install software.

“Additionally, expand investments in cybersecurity tools designed to detect and prevent anomalous activity, such as installing unrecognized software or exfiltrating sensitive data.”

Additional tips on protecting organizations against phishing attacks are available at this link.