Originally published: Nov 16, 2023. Last updated: Oct 11, 2026.
Accounting software holds your most sensitive financial data: bank details, payroll, tax records, and client information. That makes it one of the most attractive targets for cybercriminals, which is why securing it deserves as much attention as the ways accounting software can increase profit margins. This 2026 guide gives you practical, small-business-friendly steps to lock down your accounting software, from multi-factor authentication and tested backups to choosing a trustworthy vendor and meeting your legal obligations.
Before diving into defenses, it helps to know what you are up against. Cyberattacks come in many forms, and attackers specifically hunt for financial data because it can be turned into identity theft, fraudulent transfers, and ransom leverage.
Why Accounting Software Is a Prime Target
Accounting platforms are a goldmine for attackers because they concentrate everything criminals want in one place: bank account numbers, tax IDs, payroll records, and client personal data. The IBM Cost of a Data Breach 2025 report, which studied 600 breached organizations, found that phishing was the most frequent initial attack vector (16% of breaches, averaging $4.8 million each), while breaches caused by third-party vendor and supply-chain compromise averaged $4.91 million. Financial-sector breaches averaged $5.56 million. In short, the data inside your accounting system is exactly the kind of information attackers monetize fastest.
The Internal Revenue Service (IRS) and its Security Summit partners have repeatedly warned that tax and accounting professionals are among the most targeted groups, because a single compromised firm can expose hundreds of clients to identity theft. That is why protecting this software is not just good IT hygiene; for many firms, it is a professional and legal duty.
Build a Security Foundation First
You do not need an enterprise security team to start. You need one named person responsible for security and a simple framework to follow.
Name a Security Owner
The Cybersecurity and Infrastructure Security Agency (CISA) recommends that every small business designate a “Security Program Manager.” This person does not need to be a security expert or even an IT professional. Their job is to own the plan: track who has access to what, make sure updates happen, keep the backup routine, and lead the response if something goes wrong.
Follow a Proven Framework
The National Institute of Standards and Technology (NIST) publishes the Cybersecurity Framework 2.0, with a Small Business Quick-Start Guide written specifically for firms with modest or no existing security plans. It organizes security into six functions: Govern, Identify, Protect, Detect, Respond, and Recover. For a small firm, that translates into a short checklist: decide who is in charge (Govern), list your systems and data (Identify), lock them down (Protect), watch for problems (Detect), know what to do when something happens (Respond), and keep backups so you can get back on your feet (Recover).
Lock Down Access with MFA and Strong Passwords
Most breaches start with stolen or guessed login credentials. Two controls close that door.
Require Multi-Factor Authentication Everywhere
Multi-factor authentication (MFA), also called two-factor authentication, requires a second proof of identity beyond your password. The CISA lists it as one of four cybersecurity essentials for businesses, and the IRS notes that federal safeguards standards now require tax professionals to use MFA to protect client information. Start with email, remote access, and administrator accounts, then extend it to every user of your accounting software.
Not all MFA is equal. CISA ranks the options from strongest to weakest: physical security keys offer the best phishing resistance, followed by authenticator apps with number matching, then authenticator apps with one-time codes. Text-message codes are the weakest option and should be used only when nothing stronger is available for that account.
Use Strong, Unique Passwords
NIST cybersecurity basics for small businesses recommend strong passwords on every account plus a password manager, which lets you keep a long, different password for every service without memorizing them all. Current federal guidance no longer recommends forcing password changes on a fixed schedule; instead, use unique passwords everywhere and change a password immediately if it may have been compromised. Never reuse your accounting software password on another platform, and never share credentials over email or chat.
Limit Access by Role
Give each person only the access their job requires. Knowing what your bookkeepers do for a small business day to day helps you set sensible access levels: a bookkeeper entering invoices does not need the same permissions as the partner approving payments. Review who has access at least quarterly, and remove accounts the day someone changes roles or leaves.
Train Your Team Against Phishing
Since phishing is the single most common way attackers get in, your people are your most important defense. Train staff to recognize suspicious emails, unexpected attachments, and urgent requests to move money or share credentials. A common accounting scam is a fake email that looks like it comes from a vendor or client, asking you to update bank details for the next payment. Verify any payment or bank-detail change through a second channel, such as a phone call to a known number, before acting.
Make reporting easy: tell the team exactly where to forward suspicious messages and praise people who report them. If you want to test your defenses more formally, learn about the different types of penetration testing used to find weaknesses before criminals do. Broader staff-awareness practices are covered in our guide to the top cyber security measures for businesses.
Back Up and Patch Relentlessly
Ransomware works by encrypting your data and demanding payment. Reliable, tested backups take away that leverage.
- Back up automatically and continuously. Do not rely on someone remembering to run a backup on Fridays.
- Keep offline, encrypted copies. CISA advises keeping offline, encrypted backups of critical data so an attacker who reaches your network cannot also reach your backups.
- Test your restores. A backup you have never restored is a hope, not a plan. Practice restoring your accounting data at least a few times a year and confirm the numbers come back intact.
- Patch promptly. Turn on automatic updates for your operating systems and accounting software, and prioritize patches for internet-facing systems. Outdated software contains flaws attackers already know how to exploit.
- Secure the devices too. Use strong passwords on every laptop, enable disk encryption, and lock screens automatically after a few minutes idle. A stolen unlocked laptop can bypass every network control you own.
Choose Your Vendor Carefully
Whether your software runs in the cloud or on your own servers, your vendor’s security becomes your security. Cloud providers typically handle backups, off-site storage, and round-the-clock monitoring, which is why many small firms prefer cloud-based accounting software. But “cloud” is not automatically safe: vendor compromises are among the costliest breaches, so vet the provider before you trust them with your books.
When evaluating a provider, ask about independent security certifications (such as SOC 2), encryption of data in transit and at rest, detailed audit logs, how they handle security incidents, and the quality of their customer support. Read reviews from real customers, and confirm in the contract that the provider maintains appropriate safeguards for your data, which federal guidance for tax professionals specifically requires of service providers.
Staying current on where the industry is heading also helps you ask better questions of vendors. Read our overview of how technology in accounting is transforming businesses to understand the tools and trends shaping modern accounting platforms.
Put It in Writing: Your Information Security Plan
Here is the part many small firms miss: for tax and accounting professionals, a written security plan is not optional. Under the Gramm-Leach-Bliley Act, the Federal Trade Commission (FTC) considers tax and accounting professionals to be financial institutions, and its Safeguards Rule requires them to create and maintain a Written Information Security Plan (WISP) to protect client data.
A good WISP is tailored to the size and complexity of your practice and covers three areas: employee management and training, information systems, and detecting and managing system failures. The IRS and the Security Summit partners publish a free template, Publication 5708, Creating a Written Information Security Plan for Your Tax and Accounting Practice, designed especially for smaller practices. Review and update your plan regularly, and keep a digital copy stored safely in case of an emergency.
The American Institute of CPAs (AICPA) similarly urges tax practices to build a culture of cybersecurity, keeping the written plan current, systems updated, and key behaviors reinforced across the team. This article is general information, not legal advice; confirm your specific obligations with a qualified professional or your professional association.
Prepare an Incident Response Plan
Even with strong defenses, plan for the day something slips through. CISA recommends that small businesses write, maintain, and regularly practice an incident response plan that answers one simple question: who do we call, and what do we do first, if something goes wrong? Keep it to one page: who isolates affected machines, who contacts leadership and the IT provider, who notifies clients, and which vendors to call.
If you are a tax professional and client data is compromised, follow your WISP, engage IT professionals to assess the damage, and report the incident to your local IRS Stakeholder Liaison so the IRS can take steps to block fraudulent returns. Firms with limited in-house IT may also consider working with a quality cloud security consulting service to review their setup before an incident happens. Firms that handle this calmly protect not just their data, but their credibility with clients.
Modern tools can also make day-to-day operations more resilient: see our guide on how accounting software improves business efficiency for ways the right platform reduces manual risk alongside security controls.
Accounting Software Security FAQs
What is the biggest cyber threat to accounting software?
Phishing is the most common initial attack vector overall, responsible for 16% of breaches in the IBM Cost of a Data Breach 2025 report, followed closely by third-party vendor and supply-chain compromise. For accounting systems specifically, credential theft and business email compromise are the most practical day-to-day threats, because one stolen login can expose an entire client database.
Is cloud-based accounting software safer than desktop software?
Cloud software offers real advantages: automatic off-site backups, provider-run monitoring, and faster patching. But it is not automatically safer. Your security depends on the vendor’s practices, so check for independent certifications, encryption standards, and incident-response commitments before migrating, and keep your own offline backups regardless.
Do tax professionals legally need a Written Information Security Plan?
Yes. Under the Gramm-Leach-Bliley Act and the FTC Safeguards Rule, tax and accounting professionals are considered financial institutions and must create and maintain a Written Information Security Plan (WISP). The IRS and Security Summit partners provide a free template in Publication 5708, and federal standards now require these professionals to use multi-factor authentication as well.
What is multi-factor authentication and why does it matter?
Multi-factor authentication requires a second proof of identity beyond your password, such as a code from an authenticator app or a tap on a physical security key. It matters because stolen passwords are the most common way attackers get in; with MFA enabled, a stolen password alone is not enough to access your accounting software. CISA recommends the strongest available method, starting with administrator accounts.
How often should I back up my accounting data?
Continuously and automatically, with offline encrypted copies kept separate from your network. Just as important as frequency is testing: practice restoring your accounting data several times a year so you know the backups actually work before ransomware or a hardware failure forces you to find out.
What should I do if my accounting software is hacked?
Isolate the affected systems, follow your written information security plan, and bring in IT help to assess the scope. Tax professionals should also report the incident to their local IRS Stakeholder Liaison so fraudulent returns can be blocked. Then review what failed, close the gap, and update your plan so the same attack cannot succeed twice.
Final Check: Is Your Accounting Software Secure?
Securing accounting software is not a one-time project; it is a routine, like reconciling your books. Name a security owner, require multi-factor authentication, train your team against phishing, keep tested backups, patch promptly, vet your vendor, write your security plan, and practice your response. By taking proactive measures now, you protect your clients, your credibility, and the business you have worked hard to build.
