How CFOs Can Reduce ACH Payment Fraud

Ever receive an “urgent” supplier email asking to update bank account details right before a large payment goes out?

That’s exactly how many ACH fraud attacks now begin.

As businesses accelerated digital payment adoption during and after the pandemic, ACH transfers became one of the fastest-growing methods for supplier payments. But the speed of that transition also created new security gaps — especially inside accounts payable departments.

We looked at how modern ACH fraud schemes actually work, why vendor payment fraud is increasing, and what finance teams can realistically do to reduce risk. The conclusion is pretty straightforward: most ACH fraud attacks don’t happen because systems completely fail — they happen because verification processes break down under pressure.

Why ACH Payments Became a Bigger Fraud Target

ACH payments solved a lot of operational problems for businesses.

They helped companies:

• Reduce paper checks
• Automate supplier payments
• Improve remote payment workflows
• Speed up transaction processing

But faster digitization also created new vulnerabilities.

Why ACH fraud increased so quickly

During the pandemic, many AP teams had to:

• Shift to remote operations quickly
• Process payments under tighter timelines
• Handle supplier onboarding digitally

In many cases, companies simply didn’t have enough time to:

• Secure remote environments properly
• Standardize verification procedures
• Protect sensitive supplier banking data

What fraudsters noticed

Attackers quickly realized:

• Payment workflows were changing fast
• AP teams were under pressure
• Vendor verification processes were inconsistent

That created ideal conditions for fraud attempts.

What Is Vendor Email Compromise (VEC)?

This is currently one of the most common forms of ACH fraud.

Vendor email compromise attacks explained

A Vendor Email Compromise (VEC) attack usually works like this:

1. Fraudsters gain access to a supplier’s email system
2. They monitor invoice and payment activity
3. They identify upcoming large payments
4. They contact the buyer’s AP team requesting updated bank details
5. Payments get redirected to fraudulent accounts

Why these attacks work

The emails often appear legitimate because attackers:

• Use real supplier conversations
• Mimic existing invoice formatting
• Time requests strategically before payments

What makes this dangerous

The fraud often isn’t discovered until:

• The legitimate supplier reports missing payments
• Funds have already been withdrawn
• The fraudulent account has been closed

In practice: ACH fraud increasingly relies on social engineering, not just technical hacking.

Why Bank Account Update Requests Are High Risk

At first glance, changing supplier banking information seems routine.

But it’s one of the highest-risk moments in the entire payment process.

Preventing bank account update scams

Suppliers legitimately change bank accounts from time to time.

But fraudsters know:

• AP teams regularly process these requests
• Urgent payment timing creates pressure
• Employees may skip verification steps

Common red flags

Fraudulent requests often include:

• Urgent language
• Last-minute timing
• Requests to bypass standard approval processes
• Slightly altered email domains

What AP teams often miss

Even cautious teams can overlook:

• Small spelling changes in email addresses
• Fake phone numbers in signatures
• Spoofed supplier communication threads

Why manual verification matters

The safest approach is still:

• Independent callback verification
• Using previously known contact details
• Multi-step approval workflows

How Businesses Can Prevent ACH Fraud

This is where operational discipline matters most.

How to prevent ACH fraud

Strong ACH security typically starts with:

• Standardized processes
• Consistent verification
• Controlled access management

Step 1: Verify all bank account changes

Never rely solely on email requests.

Instead:

• Call verified supplier contacts directly
• Confirm changes through independent channels
• Document all verification steps

Step 2: Limit payment authorization access

Reduce risk by:

• Restricting who can modify banking data
• Separating approval responsibilities
• Using role-based access controls

Step 3: Secure vendor data properly

Sensitive supplier banking data should:

• Be encrypted
• Stored securely
• Shared only when necessary

Step 4: Train AP employees regularly

Many attacks succeed because employees:

• Are rushed
• Lack fraud awareness training
• Don’t recognize social engineering tactics

Regular fraud simulations and training help reduce mistakes significantly.

ACH Security Best Practices for AP Teams

Strong fraud prevention usually depends more on process consistency than expensive software.

Secure ACH payment processing

The safest AP teams typically use:

• Multi-step approval systems
• Repeatable verification workflows
• Detailed audit trails

Why repeatable processes matter

Fraud prevention fails when employees:

• Handle requests inconsistently
• Make exceptions under pressure
• Skip documentation steps

What secure workflows often include

A strong vendor payment workflow may require:

• Dual approvals
• Callback verification
• Internal fraud review for high-risk changes

Why finance and IT must work together

Payment fraud prevention isn’t just an accounting issue.

It also depends on:

• Secure email systems
• Network protection
• Access monitoring
• Identity verification controls

How CFOs Can Reduce Payment Fraud Risk

Leadership plays a major role here.

How CFOs can reduce payment fraud

Companies with lower fraud exposure usually:

• Prioritize payment security internally
• Invest in fraud prevention training
• Build stricter verification standards

Why executive involvement matters

Without leadership support:

• AP teams often prioritize speed over security
• Fraud controls become inconsistent
• Verification policies weaken over time

What successful organizations do differently

Strong finance teams often:

• Treat bank account changes as high-risk events
• Require documented approvals
• Conduct periodic fraud audits

What businesses should focus on

The biggest improvements often come from:

• Better process discipline
• Stronger employee awareness
• Consistent supplier verification

Not necessarily from adding more software alone.

The Future of ACH Fraud Prevention

ACH usage will likely continue growing as businesses modernize payments.

That means fraud prevention must evolve as well.

ACH fraud risks for AP teams

As payment systems become more digital:

• Fraud schemes become more sophisticated
• Social engineering attacks increase
• Supplier impersonation becomes harder to detect

What businesses should expect

Future fraud prevention will likely rely more heavily on:

• Automated validation tools
• AI-driven anomaly detection
• Stronger identity verification systems

But one thing still matters most

Even advanced systems fail if:

• Employees bypass procedures
• Verification becomes inconsistent
• Urgency overrides security controls

In short: Process discipline remains one of the strongest defenses against ACH fraud.

Conclusion

The growth of digital payments has made ACH transfers faster and more efficient for businesses — but it has also increased exposure to sophisticated fraud schemes. Modern ACH fraud prevention requires more than just technical security; it depends heavily on repeatable verification processes, employee awareness, and disciplined payment controls.

As vendor payment fraud continues evolving, businesses that strengthen supplier verification, secure banking data properly, and standardize AP workflows will be far better positioned to reduce financial risk and protect payment operations long term.