Pro Blog | PK Tech

What Are the Top Cybersecurity Vulnerabilities for CPA Firms?

Written by PK Tech | July 21, 2025

Trust is currency in today’s world. The name of the game for cybercriminals is exploiting that trust for financial gain. 

When it comes to CPA firms, there are two vulnerabilities that are consistently identified: email spoofing and invoice fraud. Increasingly common and most damaging, these types of attacks are designed to manipulate employees into transferring money or sensitive data under false pretenses.  

As you consider the top risks to your firm, let’s analyze what we know about email spoofing and invoice fraud, and what we can learn in order to stop threats before they become financial and reputational disasters. 

Why CPA Firms Are Prime Targets for Email Spoofing

CPA firms are treasure troves of sensitive financial data. They handle payroll, tax returns, wire transfers, and vendor payments, all of which make them irresistible to cybercriminals. Email spoofing attacks typically begin with an attacker crafting an email that appears to come from a known contact, often a managing partner, client, or vendor.

These spoofed emails may request urgent payment, updated banking details, or ask for confidential documents. Because CPAs work in fast-paced, deadline-driven environments, these messages can go unquestioned, especially when they’re disguised with familiar names, logos, and tone.

The stakes are high for money hungry cybercriminals. Why? One successful spoofing attempt can result in six-figure losses, compromised client data, and long-term reputational harm. A win for the cybercriminal, and a detrimental loss for the firm.

How Invoice Fraud Scams Infiltrate Accounting Workflows

Invoice fraud typically follows one of two paths: either the attacker compromises a vendor’s email account (BEC = Business Email Compromise) or creates a near-perfect spoof of an existing vendor invoice. The scammer then sends fake invoices or altered payment instructions, tricking the CPA or accounts payable team into wiring funds to fraudulent accounts.

This type of fraud thrives in environments where:
  • Vendor information is not regularly verified
  • Email authentication protocols (like SPF, DKIM, and DMARC) are weak or nonexistent
  • Staff are not trained to detect red flags in email behavior or formatting.

It’s not uncommon for firms to unknowingly pay tens of thousands of dollars to fraudulent accounts, only discovering the loss weeks later when the real vendor follows up on the "unpaid invoice."

The Human Element: How Internal Staff Become Gateways for Attack

It’s easy to assume cyberattacks are purely technical issues, but in reality, the most common vulnerabilities are human. After all, employees are, in fact, only human. Human errors happen because humans are not machines and are still integral to firm operations. That means, even with all efforts to keep error at minimum, there is still room for human error. 

Spoofing and fraud emails rely on social engineering which means they operate by manipulating people, not systems. Employees who are tired, overworked, or untrained in cybersecurity hygiene are more likely to:

  • Click malicious links
  • Download fake attachments
  • Approve suspicious wire transfers without double-checking the request

CPA firms without clear internal protocols, multi-step verification for payments, or regular cybersecurity training are sitting ducks for these attacks.

Strengthening Your Defenses: What Smart Firms Are Doing

As a managed IT provider, we help the CPA firms we work with implement a layered defense strategy that includes:

1. Email Authentication


Implementing SPF, DKIM, and DMARC protocols makes it significantly harder for attackers to spoof your domain. These are not optional in today’s threat landscape.

2. Advanced Email Filtering and Monitoring


Modern threat detection tools use AI to identify suspicious patterns in real-time, preventing fraudulent emails from ever reaching your team.

3. Mandatory User Training


Phishing simulations, invoice fraud awareness, and regular security briefings dramatically reduce the likelihood of successful attacks.

4. Payment Verification Procedures


Implementing strict approval workflows and dual-verification steps for payments and vendor updates can stop invoice fraud in its tracks.

5. Incident Response Planning


When an attack does occur, firms with a pre-defined response plan recover faster and avoid prolonged damage.

Maintaining Client Trust With Cyber Defenses 

Email spoofing and invoice fraud aren’t just IT issues, they’re business threats that hit CPA firms where it hurts most: finances, client trust, and reputation. The good news? These attacks are preventable with the right mix of technology, training, and governance.

At PK Tech, we offer tailored cybersecurity solutions designed specifically for accounting firms. If your current IT provider isn’t actively protecting you against spoofing, fraud, and social engineering attacks, it’s time to talk. Let’s secure your firm before the next fake invoice lands in your inbox.

We’re proud to offer 15 years of experience with a focus on CPA firms. We boast AICPAs SOC 2 Type II attestation, proving via third-party audit by an independent CPA firm that we passed a rigorous and comprehensive assessment of our security and privacy controls. Schedule a time to chat with our team here