Cybercriminals don’t just target large corporations anymore. Today, CPA and accounting firms have become prime targets because they manage some of the most valuable information a hacker can steal—Social Security numbers, tax returns, payroll records, banking information, and other sensitive financial data.
For firms with 20–200 employees, cybersecurity is no longer optional. It’s an essential part of protecting your clients, maintaining business continuity, and preserving your reputation.
While every firm has unique technology needs, there are 10 foundational cybersecurity controls every accounting firm should implement. These controls work together to reduce the risk of ransomware, phishing attacks, business email compromise, and unauthorized access while helping firms build a more resilient technology environment.
In this guide, we’ll explore the biggest cybersecurity threats facing CPA firms, the essential protections every firm should have, and practical steps you can take to strengthen your security posture.
Why CPA Firms Are a Prime Target for Cybercriminals
Accounting firms manage highly confidential financial information for businesses and individuals.
This includes:
- Tax returns
- Social Security numbers
- Payroll records
- Bank account information
- Financial statements
- Business ownership documents
- Personally identifiable information (PII)
Because this information is valuable on the black market, cybercriminals often view accounting firms as attractive targets.
In addition, many attacks occur during tax season when employees are working quickly, exchanging sensitive documents, and responding to a higher volume of emails.
The combination of valuable data and busy workflows makes accounting firms an appealing target.
The Most Common Cybersecurity Threats Facing CPA Firms
Understanding today’s threat landscape is the first step toward reducing risk.
Phishing Attacks
Attackers send convincing emails designed to steal passwords or install malware.
These emails often impersonate clients, financial institutions, or government agencies.
Business Email Compromise (BEC)
Cybercriminals gain access to email accounts and impersonate trusted contacts to request fraudulent wire transfers or sensitive information.
Ransomware
Malicious software encrypts files and demands payment before access is restored.
Without reliable backups, ransomware can disrupt business operations for days or even weeks.
Credential Theft
Weak or reused passwords remain one of the most common causes of unauthorized access.
Insider Mistakes
Most security incidents aren’t caused by malicious employees—they’re caused by simple human error.
Examples include:
- Clicking phishing links
- Sharing passwords
- Sending confidential information to the wrong recipient
- Using personal devices without security controls
The 10 Essential Cybersecurity Controls Every CPA Firm Needs
A strong cybersecurity program combines people, processes, and technology.
Here are ten controls every accounting firm should prioritize.
1. Multi-Factor Authentication (MFA)
Passwords alone are no longer enough.
MFA provides an additional layer of protection by requiring a second verification method before granting access.
Protect:
- Microsoft 365
- VPN connections
- Remote desktop
- Administrative accounts
- Cloud applications
2. Endpoint Detection & Response (EDR)
Modern endpoint protection continuously monitors computers and servers for suspicious activity.
Unlike traditional antivirus software, EDR helps detect and respond to advanced threats before they spread throughout your network.
3. Advanced Email Security
Email remains the primary delivery method for phishing attacks.
Advanced filtering can:
- Block malicious attachments
- Identify suspicious links
- Detect impersonation attempts
- Reduce spam
4. Security Awareness Training
Technology alone isn’t enough.
Regular employee training helps staff recognize phishing emails, social engineering tactics, and other common cyber threats.
Quarterly training combined with phishing simulations helps reinforce good security habits.
5. Secure Backup & Disaster Recovery
Backups should be:
- Encrypted
- Automatically monitored
- Tested regularly
- Protected against ransomware
A backup strategy should focus on restoring business operations—not simply storing copies of files.
6. Vulnerability Management
Technology changes constantly.
Routine vulnerability scans identify outdated software, missing patches, and security weaknesses before attackers do.
7. Patch Management
Software vendors release security updates throughout the year.
Applying patches promptly helps close vulnerabilities that cybercriminals actively exploit.
8. Least Privilege Access
Employees should have access only to the systems and information necessary to perform their jobs.
Reducing unnecessary administrative privileges limits the potential damage from compromised accounts.
9. Microsoft 365 Security Hardening
Microsoft 365 offers extensive security capabilities—but many organizations never configure them properly.
Important settings include:
- Conditional Access
- Microsoft Defender
- Data Loss Prevention
- Safe Links
- Safe Attachments
- Administrative alerts
10. Continuous Security Monitoring
Cybersecurity isn’t a one-time project.
Continuous monitoring helps identify suspicious activity, failed login attempts, unusual behavior, and emerging threats before they become major incidents.
Building a Cybersecurity Roadmap
Improving cybersecurity doesn’t require replacing everything overnight.
A phased approach is often the most effective.
First 30 Days
Focus on the highest-impact improvements.
- Enable MFA
- Deploy endpoint protection
- Verify backups
- Patch critical systems
- Review administrative accounts
Next 60–90 Days
Expand your security program.
- Launch employee training
- Strengthen Microsoft 365
- Conduct vulnerability scanning
- Review password policies
- Update documentation
Ongoing
Cybersecurity requires continuous improvement.
Establish recurring activities such as:
- Quarterly security reviews
- Backup testing
- Security awareness training
- Technology planning
- Incident response exercises
Common Cybersecurity Mistakes We See
Many firms assume they’re adequately protected until a security assessment reveals hidden risks.
Common issues include:
- Everyone has local administrator access
- Multi-Factor Authentication isn’t enabled everywhere
- Former employees still have active accounts
- Backups have never been tested
- Passwords are shared between employees
- Unsupported Windows devices remain in production
- Microsoft 365 security settings use default configurations
- Employees receive little or no cybersecurity training
Fortunately, these issues can usually be addressed through a structured improvement plan.
Example: Improving Security Before Tax Season
Imagine a 75-person CPA firm preparing for tax season.
Leadership was concerned about phishing attacks and increasing cybersecurity risks.
Working with a managed IT provider, the firm implemented:
- Multi-Factor Authentication
- Endpoint Detection & Response
- Advanced email filtering
- Quarterly security awareness training
- Backup monitoring
As a result, the firm significantly improved its visibility into security threats while reducing the likelihood of successful phishing attacks during its busiest time of year.
Frequently Asked Questions
Is antivirus software enough?
No. Modern cybersecurity requires multiple layers of protection including endpoint detection, email security, MFA, monitoring, backups, and employee training.
Should small CPA firms invest in cybersecurity?
Absolutely. Smaller firms are frequently targeted because attackers assume they have fewer security resources.
How often should employees complete cybersecurity training?
Most firms benefit from quarterly training combined with regular phishing simulations.
How often should backups be tested?
At a minimum, backup recovery should be tested several times each year to ensure data can be restored successfully.
How do we know if our firm has security gaps?
The best place to start is with a cybersecurity assessment that reviews your current technology, policies, and security controls.
Why CPA Firms Choose CW IT Support
At CW IT Support, we help organizations build secure technology environments that support productivity, compliance, and long-term business success.
Our cybersecurity-first approach includes proactive monitoring, technology planning, security assessments, and practical recommendations that reduce business risk without adding unnecessary complexity.
Whether you’re strengthening your defenses, preparing for cyber insurance renewal, or planning future technology investments, we’re committed to helping your firm make informed cybersecurity decisions.
Ready to Strengthen Your Cybersecurity?
Cybersecurity isn’t just about preventing attacks—it’s about protecting your clients, maintaining business continuity, and giving your team confidence that your technology is secure.
If you’re unsure where your firm stands today, a cybersecurity assessment is an excellent first step.
Contact CW IT Support to schedule a cybersecurity assessment and discover practical ways to improve your firm’s security posture.