When most people think of insider threats, they picture a disgruntled employee or a careless staff member clicking on a phishing link. That image is only part of the story. In reality, insiders are defined as anyone with authorized access to an organization’s systems, data, or facilities. This definition includes contractors, vendors, and partners. The Cybersecurity and Infrastructure Security Agency (CISA) makes this clear by noting that insiders are not limited to employees but also include vendors, custodians, repair personnel, and anyone given access to sensitive systems or information.
This broader definition matters because modern enterprises rely heavily on third parties. Cloud providers, IT service firms, outsourced HR teams, and even subcontractors all operate inside the trust boundary. They may not be on the payroll, but they are insiders in practice.
How Third Parties Become Insider Threat Actors
Trusted access by design
Third parties are often granted credentials, devices, or direct network access to perform their duties. This access makes them insiders whether or not they are formally part of the organization.
Privileged knowledge of operations
External partners may understand business strategies, pricing models, intellectual property, or technical systems. That knowledge can be weaponized for espionage, sabotage, or theft.
Exploitation by adversaries
Attackers frequently target third parties with weaker defenses. Once compromised, these accounts become a bridge into the primary organization. The hacking collective Scattered Lapsus$ Hunters, for example, claimed to exploit a third party vendor called Gainsight to infiltrate Salesforce customers and even attempted to leverage insider access at CrowdStrike.
Malicious intent
Nation state operatives have posed as contractors to infiltrate Western companies. DTEX Systems highlighted how North Korean IT workers used falsified identities to gain employment, access source code, and funnel data back to their government.
Negligence or mismanagement
Sometimes the threat is not intentional. A contractor might mishandle sensitive data or fail to secure their accounts. OpenText Cybersecurity described how criminals bribed a third party call center contractor working for Coinbase, leading to a breach that exposed customer data.
Why This Risk Is Growing
The extended workforce is now a permanent feature of business. Outsourcing, cloud adoption, and interconnected supply chains expand the attack surface. Ramsey Theory Group recently warned that third party SaaS and AI supply chain compromises are among the most significant risks facing enterprises as they close out 2025. The more organizations rely on external partners, the more opportunities exist for insider exploitation.
Mitigation Strategies
To reduce third party insider risk, organizations should:
- Map all external access points including vendors and contractors.
- Apply least privilege principles to third-party accounts.
- Continuously monitor behavior with insider risk management tools.
- Vet subcontractors as rigorously as direct employees.
- Include third party scenarios in insider threat programs.
Closing Thought
Third party insider threats are not hypothetical. They are happening now, from contractors bribed in call centers to insiders at cybersecurity firms selling access to hackers. Every trusted relationship carries risk. Security leaders must recognize that insiders are not always employees and build programs that account for the extended workforce. Trust without verification is a liability, and in today’s interconnected world, it is often the weakest link.
Sources
- CrowdStrike insider case, SecurityWeek: link
- CrowdStrike insider case, TechStory: link
- CrowdStrike insider case, Information Age: link
- CISA definition of insider threats: link
- DTEX Systems on third-party insider risk: link
- OpenText on insider threats and Coinbase breach: link
- Ramsey Theory Group on supply chain risks: link
Leave a Reply