When a staff member leaves an organisation, there’s often a flurry of farewells, HR admin, and handover checklists. But amidst the departure logistics, many organisations overlook one crucial risk: the shadow employee. These are former staff members who retain access to company systems, data, or platforms long after their exit, posing a serious threat to business continuity, security, and brand integrity. This phenomenon is closely related to the broader issue of “shadow IT”, where employees use unauthorised software and services without IT department approval.
The reality is more common than most would like to believe. According to research, 89% of ex-employees still have valid login credentials, and 45% can access confidential data. Alarmingly, almost half admit to using these credentials after leaving. This isn’t just a technical oversight; it’s a cybersecurity blind spot that could lead to significant data breaches and unauthorised access.
Shadow employees: the hidden insider threat
Imagine a marketer who left their role months ago but still has access to shared cloud drives or collaboration tools. A cached login or overlooked folder can easily become a breach point. In one scenario, an ex-employee accidentally uploads a shared corporate folder to their personal cloud services. If that link becomes public, competitors or cybercriminals could gain access to highly sensitive company data, expanding the organisation’s attack surface and creating potential compliance violations.
“The shadow employee phenomenon is more common than many realise, particularly in organisations with high staff turnover or fragmented and cloud-based systems,” says Anna Collard, SVP Content Strategy and Evangelist at KnowBe4 Africa. “It’s a prime example of how shadow IT can create significant cybersecurity risks and blind spots.”
She adds that these lapses happen not out of malice but due to siloed processes. “Access management often prioritises onboarding. Offboarding tends to fall through the cracks, especially when IT and HR don’t coordinate or access isn’t centrally managed,” Collard explains. “This isn’t just a system failure; it’s a human process issue that requires robust security policies, employee training, and effective password management.”
When rogue access becomes a crisis
The consequences of overlooking a shadow employee can be severe. In one notable case, a U.S. company suffered a major data breach after a former IT contractor’s access was never revoked. The incident cost the company six figures in settlements and loss of client contracts, highlighting the financial risks and legal implications of inadequate offboarding processes.
“The risks are serious and multifaceted,” Collard warns. “They span operational disruptions, reputational damage, and financial penalties. It’s a critical aspect of risk management that many organisations overlook, leading to potential security incidents.”
Operationally, former employees with lingering access can inadvertently alter systems, leak information, or disrupt services. Reputationally, such breaches erode customer trust. “Even if the breach is unintentional, customers don’t care; it’s your brand’s name in the headlines,” she notes.
From a financial perspective, these breaches often result in hefty regulatory fines and legal costs. “Many organisations still treat offboarding like a box-ticking HR task, not a cybersecurity event,” says Collard. “That mindset needs to change if they want to reduce these vulnerabilities and improve their overall security posture against cyber threats.”
Offboarding as a security priority
Preventing shadow employee risks starts with redefining offboarding. It should be a collaborative process that includes HR, IT, and security teams, focusing on comprehensive identity management and access control.
“It begins with a shift in mindset; offboarding must be treated as a crucial security control, not just admin,” says Collard. She advises using automation tools to revoke access in real-time, ensuring no lag between exit and deactivation. This approach is essential for maintaining strong IT governance and mitigating insider threats.
In addition, organisations should perform regular compliance audits and security audits to identify dormant accounts, shadow IT usage, and unapproved applications that may not be captured in formal access controls. These audits are crucial for uncovering potential security gaps and ensuring regulatory compliance.
“Line managers must be made accountable for flagging all systems their teams use, especially unofficial or unsanctioned ones,” Collard notes. She also highlights how the rise of AI has added a new layer to the problem, further complicating risk assessment efforts.
“We’re seeing the emergence of ‘shadow AI where employees use generative AI tools from work devices, often sharing sensitive data without formal policies in place. This creates another layer of risk if those employees leave and still retain access,” she warns. This trend underscores the need for comprehensive security awareness training and clear policies on technology adoption.
Digital keys must be returned
As hybrid and remote work become the norm, so too do decentralised digital ecosystems. In this context, the concept of access must evolve beyond traditional network credentials to encompass cloud services, SaaS applications, and various third-party platforms.
“Former employees should not keep the digital keys to your kingdom,” concludes Collard. “Modern businesses must prioritise secure, structured offboarding processes as a core element of their cybersecurity hygiene. This includes implementing robust data loss prevention measures and considering multi-factor authentication for critical systems.”
The shadow employee may be out of sight, but if left unchecked, they’re never truly gone. By treating offboarding as a critical security event and implementing comprehensive access management strategies, organisations can significantly reduce their vulnerability to this often-overlooked threat and strengthen their overall IT governance.
