KrebsOnSecurity recently heard from a reader whose boss’s email account got phished and was used to trick one of the company’s customers into sending a large payment to scammers. An investigation into the attacker’s infrastructure points to a long-running Nigerian cybercrime ring that is actively targeting established companies in the transportation and aviation industries.

Image: Shutterstock, Mr. Teerapon Tiuekhom.

A reader who works in the transportation industry sent a tip about a recent successful phishing campaign that tricked an executive at the company into entering their credentials at a fake Microsoft 365 login page. From there, the attackers quickly mined the executive’s inbox for past communications about invoices, copying and modifying some of those messages with new invoice demands that were sent to some of the company’s customers and partners.

Speaking on condition of anonymity, the reader said the resulting phishing emails to customers came from a newly registered domain name that was remarkably similar to their employer’s domain, and that at least one of their customers fell for the ruse and paid a phony invoice. They said the attackers had spun up a look-alike domain just a few hours after the executive’s inbox credentials were phished, and that the scam resulted in a customer suffering a six-figure financial loss.

The reader also shared that the email addresses in the registration records for the imposter domain — [email protected] — is tied to many such phishing domains. Indeed, a search on this email address at DomainTools.com finds it is associated with at least 240 domains registered in 2024 or 2025. Virtually all of them mimic legitimate domains for companies in the aerospace and transportation industries worldwide.

An Internet search for this email address reveals a humorous blog post from 2020 on the Russian forum hackware[.]ru, which found [email protected] was tied to a phishing attack that used the lure of phony invoices to trick the recipient into logging in at a fake Microsoft login page. We’ll come back to this research in a moment.

JUSTY JOHN

DomainTools shows that some of the early domains registered to [email protected] in 2016 include other useful information. For example, the WHOIS records for alhhomaidhicentre[.]biz reference the technical contact of “Justy John” and the email address [email protected].

A search at DomainTools found [email protected] has been registering one-off phishing domains since at least 2012. At this point, I was convinced that some security company surely had already published an analysis of this particular threat group, but I didn’t yet have enough information to draw any solid conclusions.

DomainTools says the Justy John email address is tied to more than two dozen domains registered since 2012, but we can find hundreds more phishing domains and related email addresses simply by pivoting on details in the registration records for these Justy John domains. For example, the street address used by the Justy John domain axisupdate[.]net — 7902 Pelleaux Road in Knoxville, TN — also appears in the registration records for accountauthenticate[.]com, acctlogin[.]biz, and loginaccount[.]biz, all of which at one point included the email address [email protected].

That Rsmith Gmail address is connected to the 2012 phishing domain alibala[.]biz (one character off of the Chinese e-commerce giant alibaba.com, with a different top-level domain of .biz). A search in DomainTools on the phone number in those domain records — 1.7736491613 — reveals even more phishing domains as well as the Nigerian phone number “2348062918302” and the email address [email protected].

DomainTools shows [email protected] appears in the registration records for the domain seltrock[.]com, which was used in the phishing attack documented in the 2020 Russian blog post mentioned earlier. At this point, we are just two steps away from identifying the threat actor group.

The same Nigerian phone number shows up in dozens of domain registrations that reference the email address [email protected], including 26i3[.]net, costamere[.]com, danagruop[.]us, and dividrilling[.]com. A Web search on any of those domains finds they were indexed in an “indicator of compromise” list on GitHub maintained by Palo Alto Networks‘ Unit 42 research team.

SILVERTERRIER

According to Unit 42, the domains are the handiwork of a vast cybercrime group based in Nigeria that it dubbed “SilverTerrier” back in 2014. In an October 2021 report, Palo Alto said SilverTerrier excels at so-called “business e-mail compromise” or BEC scams, which target legitimate business email accounts through social engineering or computer intrusion activities. BEC criminals use that access to initiate or redirect the transfer of business funds for personal gain.

Palo Alto says SilverTerrier encompasses hundreds of BEC fraudsters, some of whom have been arrested in various international law enforcement operations by Interpol. In 2022, Interpol and the Nigeria Police Force arrested 11 alleged SilverTerrier members, including a prominent SilverTerrier leader who’d been flaunting his wealth on social media for years. Unfortunately, the lure of easy money, endemic poverty and corruption, and low barriers to entry for cybercrime in Nigeria conspire to provide a constant stream of new recruits.

BEC scams were the 7th most reported crime tracked by the FBI’s Internet Crime Complaint Center (IC3) in 2024, generating more than 21,000 complaints. However, BEC scams were the second most costly form of cybercrime reported to the feds last year, with nearly $2.8 billion in claimed losses. In its 2025 Fraud and Control Survey Report, the Association for Financial Professionals found 63 percent of organizations experienced a BEC last year.

Poking at some of the email addresses that spool out from this research reveals a number of Facebook accounts for people residing in Nigeria or in the United Arab Emirates, many of whom do not appear to have tried to mask their real-life identities. Palo Alto’s Unit 42 researchers reached a similar conclusion, noting that although a small subset of these crooks went to great lengths to conceal their identities, it was usually simple to learn their identities on social media accounts and the major messaging services.

Palo Alto said BEC actors have become far more organized over time, and that while it remains easy to find actors working as a group, the practice of using one phone number, email address or alias to register malicious infrastructure in support of multiple actors has made it far more time consuming (but not impossible) for cybersecurity and law enforcement organizations to sort out which actors committed specific crimes.

“We continue to find that SilverTerrier actors, regardless of geographical location, are often connected through only a few degrees of separation on social media platforms,” the researchers wrote.

FINANCIAL FRAUD KILL CHAIN

Palo Alto has published a useful list of recommendations that organizations can adopt to minimize the incidence and impact of BEC attacks. Many of those tips are prophylactic, such as conducting regular employee security training and reviewing network security policies.

But one recommendation — getting familiar with a process known as the “financial fraud kill chain” or FFKC — bears specific mention because it offers the single best hope for BEC victims who are seeking to claw back payments made to fraudsters, and yet far too many victims don’t know it exists until it is too late.

Image: ic3.gov.

As explained in this FBI primer, the International Financial Fraud Kill Chain is a partnership between federal law enforcement and financial entities whose purpose is to freeze fraudulent funds wired by victims. According to the FBI, viable victim complaints filed with ic3.gov promptly after a fraudulent transfer (generally less than 72 hours) will be automatically triaged by the Financial Crimes Enforcement Network (FinCEN).

The FBI noted in its IC3 annual report (PDF) that the FFKC had a 66 percent success rate in 2024. Viable ic3.gov complaints involve losses of at least $50,000, and include all records from the victim or victim bank, as well as a completed FFKC form (provided by FinCEN) containing victim information, recipient information, bank names, account numbers, location, SWIFT, and any additional information.