An employee leaves your company on a Friday. By Monday, their email account is disabled, and their laptop is sitting back on the IT shelf.
Everything looks complete.
But what about the project management platform they signed up for last year? What about the cloud storage folder they shared with an outside contractor? Or the CRM account they still have from a previous role?
In many businesses, nobody checks those accounts.
Months later, those logins may still be active.
These forgotten accounts are known as zombie accounts. They are one of the most common security gaps in modern businesses. They rarely happen because someone ignored company policy. Instead, they happen because employee offboarding has not kept up with the way companies use software today.
Years ago, IT teams only had a handful of business applications to manage. Today, even small businesses often rely on dozens or even hundreds of cloud services. If your offboarding process only covers laptops and email accounts, it probably leaves important systems behind.
A zombie account is an active user account that belongs to someone who no longer works for your organization.
The name may sound informal, but the security risk is very real.
Unlike many cybersecurity threats, there is nothing suspicious about these accounts. They were created legitimately. The employee was given permission to access company data while they worked for the business.
When they leave, however, those permissions should disappear.
If they do not, the account remains fully valid. A former employee can still sign in if they know the password. Even worse, if their credentials are stolen after they leave the company, an attacker could gain access without triggering immediate suspicion.
Because the account was originally authorized, many security systems see nothing unusual.
Industry research has found that roughly half of organizations have discovered former employees still accessing SaaS applications months after their employment ended. In many cases, those accounts were found by accident rather than through a planned security review.
That makes zombie accounts a silent risk that can remain hidden for months or even years.
Modern businesses depend on Software as a Service (SaaS) applications for almost every department.
Marketing teams use design and survey platforms. Sales teams rely on customer relationship management tools. Operations teams work inside project management software. Finance uses cloud accounting systems. Employees also sign up for specialized tools that help them do their jobs faster.
Many of these applications are not managed directly by IT.
Some are purchased by department managers. Others are created using nothing more than a company email address.
When an employee leaves, the organization usually disables Microsoft 365 or Google Workspace access. Unfortunately, that does not automatically remove access to every application connected to that email address.
As businesses adopt more cloud services, this problem continues to grow.
Cloud storage services are one of the biggest sources of zombie accounts.
Platforms like Microsoft OneDrive, Google Drive, and Dropbox make collaboration simple, but they also make it easy to lose track of permissions.
Employees often:
When the employee leaves, their company account may be disabled, but those shared folders and external permissions often remain.
If no one reviews those settings, sensitive business information can stay available long after the employee has gone.
Many business applications are managed outside the IT department.
Platforms such as Asana, Monday.com, Jira, Notion, HubSpot, and Salesforce are frequently administered by department leaders instead of IT staff.
That creates a visibility problem.
If the offboarding checklist only covers centrally managed systems, these applications may never be reviewed.
A former project manager could still access planning documents. A previous sales representative might still have access to customer records. A former executive could retain visibility into confidential business plans.
None of these situations require a malicious employee to become a security problem. An unused account with outdated credentials is valuable enough for an attacker.
This is often the highest-risk category.
Employees regularly create accounts using their work email without involving IT.
Examples include:
These applications may never appear on an official software inventory.
When the employee leaves, nobody knows the accounts exist.
The accounts continue operating, often connected to company data or documents, while the business assumes access has already been removed.
Finding zombie accounts does not require expensive security software. It starts with a structured review of your cloud applications and former employees.
Begin by identifying every cloud application your business uses.
If you use an identity platform such as Microsoft Entra ID, Google Workspace Admin, or Okta, export a list of connected applications.
Then look beyond your identity provider.
Review:
Research from Grip Security’s 2025 SaaS Security Risks Report analyzed 29 million user accounts and identified nearly 24,000 unique SaaS applications across customer environments.
Even more concerning, the report found that approximately 90% of those applications were outside formal IT management.
Most businesses underestimate how many cloud services employees actually use.
Even a 30-minute review can uncover applications that have never been documented.
Next, review everyone who has left your company during the past year.
For each person, compare their name against every application in your inventory.
Ask a few simple questions:
If an account belongs to someone who no longer works for your organization, it should be treated as a zombie account until proven otherwise.
Document every finding before removing access.
Once you identify unnecessary accounts, revoke access immediately.
Keep records of what was removed, when it was removed, and who approved the change.
Then update your offboarding checklist.
Instead of focusing only on laptops and email accounts, include every business application employees may use.
As part of that process, require multi-factor authentication on all remaining active accounts and schedule regular reviews of user access.
Quarterly access reviews help ensure forgotten accounts do not remain active for long periods.
The goal is not simply to perform one cleanup. It is to create a repeatable security process.
Employee offboarding is no longer just an IT task.
It is a cybersecurity process.
Every employee departure creates an opportunity for forgotten accounts to remain connected to company systems. As organizations adopt more cloud services, that risk continues to grow.
Regular SaaS audits help identify those gaps before they become security incidents.
By maintaining a complete software inventory, reviewing user access after every employee departure, and performing scheduled access audits throughout the year, businesses can dramatically reduce unnecessary risk.
The process does not need to be complicated.
It simply needs to reflect the way modern businesses actually use software.
Zombie accounts cannot be removed if nobody knows they exist.
A SaaS access audit is one of the simplest ways to improve your organization’s security posture and reduce unnecessary risk.
If you want help reviewing your cloud applications, identifying forgotten accounts, or building a repeatable offboarding process, Caldera Cybersecurity can help. We work with small and midsized businesses to strengthen identity security, improve access management, and close the gaps that traditional offboarding processes often miss.
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This Article has been Republished with Permission from The Technology Press.