Shifting tactics fuel surge in business email compromise

Cybercriminal activity around business email compromise is accelerating. Microsoft observes a significant trend in attackers’ use of platforms, like BulletProftLink, a popular platform for creating industrial-scale malicious mail campaigns. BulletProftLink sells an end-to-end service including templates, hosting, and automated services for BEC. Adversaries using this CaaS receive credentials and the IP address of the victim.

BEC threat actors then purchase IP addresses from residential IP services matching the victim’s location creating residential IP proxies which empower cybercriminals to mask their origin. Now, armed with localized address space to support their malicious activities in addition to usernames and passwords, BEC attackers can obscure movements, circumvent “impossible travel” flags, and open a gateway to conduct further attacks. Microsoft has observed threat actors in Asia and an Eastern European nation most frequently deploying this tactic.

Impossible travel is a detection used to indicate that a user account might be compromised. These alerts flag physical restrictions that indicate a task is being performed in two locations, without the appropriate amount of time to travel from one location to the other.

The specialization and consolidation of this sector of the cybercrime economy could escalate the use of residential IP addresses to evade detection. Residential IP addresses mapped to locations at scale provide the ability and opportunity for cybercriminals to gather large volumes of compromised credentials and access accounts. Threat actors are using IP/proxy services that marketers and others may use for research to scale these attacks. One IP service provider, for example, has 100 million IP addresses that can be rotated or changed every second.

While threat actors use phishing-as-a-service like Evil Proxy, Naked Pages, and Caffeine to deploy phishing campaigns and obtain compromised credentials, BulletProftLink offers a decentralized gateway design, which includes Internet Computer public blockchain nodes to host phishing and BEC sites, creating an even more sophisticated decentralized web offering that’s much harder to disrupt. Distributing these sites’ infrastructure across the complexity and evolving growth of public blockchains makes identifying them, and aligning takedown actions, more complex. While you can remove a phishing link, the content remains online, and cybercriminals return to create a new link to existing CaaS content.

Successful BEC attacks cost organizations hundreds of millions of dollars annually. In 2022, the FBI’s Recovery Asset Team initiated the Financial Fraud Kill Chain on 2,838 BEC complaints involving domestic transactions with potential losses of over USD$590 million.

Although the financial implications are significant, wider long-term damages can include identity theft if personally identifiable information (PII) is compromised, or loss of confidential data if sensitive correspondence or intellectual property are exposed in malicious email and message traffic.

Although threat actors have created specialized tools to facilitate BEC, including phishing kits and lists of verified email addresses targeting C-Suite leaders, accounts payable leads and other specific roles, enterprises can employ methods to pre-empt attacks and mitigate risk.

For example, a domain-based message authentication, reporting, and conformance (DMARC) policy of “reject” provides the strongest protection against spoofed email, ensuring that unauthenticated messages are rejected at the mail server, even before delivery. Additionally, DMARC reports provide a mechanism for an organization to be made aware of the source of an apparent forgery, information that they would not normally receive.

Although organizations are a few years into managing fully remote or hybrid workforces, rethinking security awareness in the hybrid work era is still needed. Because employees are working with more vendors and contractors, thereby receiving more “first seen” emails, it’s imperative to be conscious of what these changes in work rhythms and correspondence mean for your attack surface.

Threat actors’ BEC attempts can take many forms – including phone calls, text messages, emails, or social media messages. Spoofing authentication request messages and impersonating individuals and companies are also common tactics.

A good first defensive step is strengthening policies for accounting, internal controls, payroll, or human resource departments on how to respond when requests or notifications of changes regarding payment instruments, banking or wire transfers are received. Taking a step back to sideline requests that suspiciously do not follow policies, or contacting a requesting entity through its legitimate site and representatives, can save organizations from staggering losses.

BEC attacks offer a great example of why cyber risk needs to be addressed in a cross-functional way with executives and leaders, finance employees, human resource managers and others with access to employee records like Social Security numbers, tax statements, contact info, and schedules, at the table alongside IT, compliance, and cyber risk officers.

Learn more about BEC and Iranian threat actors with insights from Simeon Kakpovi, Senior Threat Intelligence Analyst.