Password spraying attacks are one of the fastest-growing threats to CPA firms—and many don’t even know they’re vulnerable. By using one common password across hundreds of accounts, attackers bypass lockout alerts and quietly breach small businesses. In this article, we explain how password spraying works, why it targets CPA firms, and the simple tools that can prevent it—like strong password policies, MFA, and suspicious login monitoring.
Most cyberattacks come with warning signs—pop-ups, phishing emails, suspicious links. But password spraying is different. It’s quiet. It’s efficient. And if your firm isn’t prepared, it could let an attacker walk right through your front door—undetected.
Here’s what CPA firm leaders need to know about this rising threat, and the simple protections that can stop it.
What Is Password Spraying?
Unlike traditional brute-force attacks that target a single account with thousands of password attempts, password spraying flips the strategy. It takes one weak password—like Spring2024!—and tries it across hundreds or thousands of accounts.
By spreading out the attempts and avoiding rapid-fire logins on a single account, attackers fly under the radar of most lockout policies and monitoring tools.
For CPA firms, this is especially dangerous because:
- Staff often reuse common passwords
- Many cloud tools don’t alert on dispersed login attempts
- Just one exposed email + weak password can open the door to your entire environment
How Attackers Get In
It doesn’t take much technical skill to launch a password spraying attack. Most follow this pattern:
- Gather emails/usernames — Often from public directories, social media, or previous breaches
- Select 5–10 common passwords — Usually seasonal, company-themed, or default credentials
- Automate the attack — Bots attempt logins slowly, one password per round, across dozens or hundreds of accounts
- Wait for success — If even one user uses a weak password, the attacker is in—and often undetected
Because the attack is quiet and distributed, traditional detection methods miss it.
What Makes CPA Firms a Target?
- You handle financial and identity-rich data
- Many firms rely on basic cloud tools without layered security
- Smaller firms may lack internal IT or policy enforcement
Even if you don’t think your firm is “big enough” to be targeted, your client data is. And attackers love it when smaller firms don’t have detection systems in place.
How to Stop Password Spraying (Before It Starts)
The good news? You can block most spraying attacks with just a few smart moves—no IT overhaul required.
- Enforce Strong, Unique Passwords
- Require passwords to be at least 12 characters, with complexity
- Block common passwords (e.g., company name + year)
- Use a password manager to generate and store unique credentials
Office Heroes can help enforce these policies organization-wide, so weak passwords don’t slip through.
2. Require Multi-Factor Authentication (MFA)
Even if a password is stolen, MFA prevents access without a second verification step. CPA firms should use MFA across:
- Email and Microsoft 365 accounts
- QuickBooks and other financial platforms
- Cloud storage tools like SharePoint and OneDrive
MFA is one of the most effective protections against all forms of credential attacks, including spraying.
3. Detect Suspicious Login Patterns
Basic monitoring may miss spraying attempts, but smarter systems watch for:
- Login attempts from a single location to many accounts
- Failed logins followed by a successful one
- Login attempts during off-hours or from unusual regions
Office Heroes includes suspicious login monitoring and reporting as part of our user protection stack.
4. Train Staff to Spot and Report Issues
Password spraying often follows phishing—attackers test credentials after tricking staff. Ongoing phishing simulations and security training help users spot suspicious activity and respond early.
We help CPA firms run non-disruptive simulations and auto-enroll repeat clickers into refresher training.
Common Mistakes That Make Password Spraying Easier
- Reusing the same password across platforms
- Failing to enforce minimum complexity rules
- Relying solely on Microsoft’s built-in alerts
- Ignoring small login anomalies (“probably nothing” moments)
- Leaving accounts active after an employee leaves
If you recognize any of these, you’re not alone—but it’s time to tighten the reins.
Final Word: This Threat Doesn’t Announce Itself
Password spraying isn’t flashy—but it works. And once attackers are in, they can escalate privileges, steal client data, and even trigger costly regulatory penalties.
At Office Heroes, we help CPA firms:
- Enforce secure password policies and MFA
- Monitor logins and respond to suspicious activity
- Identify if your credentials are already circulating on the dark web
- Train your team to stay alert and resilient
Want to know if your firm’s credentials are already exposed?
Let’s run a free credential scan and review simple steps you can take today to stop password spraying cold.
