December 2025 will be remembered as an anomaly in an otherwise turbulent year for insider driven security failures. While 2025 saw an unprecedented wave of malicious insiders, compromised employees, and trusted access abuse, including cybersecurity professionals weaponizing their own privileged roles, December itself delivered something unusual: no confirmed insider driven breaches.
But that absence is misleading.
Instead of malicious employees or negligent insiders triggering new breaches, December exposed something far more structural and far more dangerous: systemic insider risk conditions embedded deep within the digital supply chain, SaaS ecosystems, and enterprise infrastructure. These conditions did not require a malicious employee to cause harm. They simply required an attacker to step into the shoes of an insider.
December’s incidents reveal a truth security leaders can no longer ignore:
Insider threat is no longer a person. It is an access condition.
And December 2025 made that clearer than ever.
A Quiet Month, But Not a Safe One
According to breach reporting from December 7 to 14, 2025, the month was unusually quiet in terms of new breaches. There were no headline dominating insider attacks, no rogue employees stealing data, and no internal sabotage events disclosed during this period.
But this quiet surface masked a deeper problem.
December’s disclosures were dominated by:
- Delayed breach notifications from earlier intrusions
- Third party and supplier compromises
- Long dwell external actors who operated with insider level access
- Weak authorization controls that allowed attackers to impersonate legitimate users
As Enginerds reported, December’s breach activity was less about detonations and more about aftershocks. Many incidents originated months earlier but only became public due to notification deadlines and forensic backlogs.
This lag is itself an insider risk signal.
If attackers can operate inside networks for months without detection, the organization is functionally blind to insider misuse as well.
Systemic Insider Risk Conditions Exposed in December
Even without direct insider driven breaches, December revealed multiple structural weaknesses that create fertile ground for insider threats, whether malicious, negligent, or compromised.
Below are the most significant insider risk conditions highlighted by December’s reporting.
1. Long Term Undetected Access
December’s disclosures showed that many organizations were only now reporting breaches that occurred months earlier, some dating back to August and October.
This extended dwell time means:
- Attackers operated with persistent, insider like access
- Internal monitoring failed to detect anomalous behavior
- Privileged accounts were likely used or impersonated
- Sensitive data was accessed without triggering alerts
When an external actor can behave like an insider for months, the distinction between external breach and insider threat becomes meaningless.
This is the core of modern insider risk.
If your detection window is measured in months, every attacker becomes an insider.
2. Supplier and Third Party Weaknesses
December reporting emphasized the role of supplier compromises as force multipliers. A breach at Asus, for example, created downstream exposure for multiple organizations relying on its software supply chain.
This is insider risk in its purest modern form:
- A trusted vendor becomes an unintentional insider
- Their compromise becomes your compromise
- Their access becomes indistinguishable from legitimate internal activity
Organizations increasingly rely on SaaS, CRM platforms, marketing tools, and cloud integrations. Each one expands the insider perimeter, often without corresponding visibility or control.
3. Intellectual Property Theft Without Insider Detection
Even when customer data was spared, attackers stole source code and proprietary IP during December disclosed incidents.
This is a critical insider risk signal:
- IP theft is traditionally associated with malicious insiders
- But December showed attackers stealing IP while masquerading as legitimate internal users
- Weak monitoring of internal repositories allowed undetected access
The line between insider theft and external theft via insider level access is now razor thin.
4. The Breach Lag Problem
Enginerds described December 7 to 14 as the week when breach lag became a strategic liability.
This lag, the months long gap between intrusion and disclosure, is a hallmark of insider risk immaturity:
- Slow investigations
- Incomplete forensic visibility
- Fragmented logs
- Overreliance on external notifications
- Lack of behavioral analytics
If organizations cannot rapidly detect external misuse of internal accounts, they are even less prepared to detect actual insiders misusing their access.
Why December’s Silence Matters
The absence of confirmed insider driven breaches in December is not a sign of progress. It is a sign of detection gaps.
Meanwhile, the year end insider threat analysis published December 19 paints a very different picture of 2025 overall. Cybersecurity professionals themselves became some of the most damaging insiders of the year, abusing privileged access, selling exploits, and sabotaging systems.
December’s quiet month sits in stark contrast to this broader trend.
This contrast suggests:
- Insider attacks may be occurring but not yet detected
- Organizations may be misclassifying insider incidents as external breaches
- Structural weaknesses are enabling insider like access without insider attribution
- The industry still lacks the behavioral visibility needed to distinguish insider misuse from external compromise
In other words:
December was not calm. It was blind.
The Strategic Takeaway for 2026
December 2025 should be treated as a warning, not a reprieve.
It demonstrated that:
- Insider risk conditions are everywhere
- External attackers increasingly operate as insiders
- Third party access is indistinguishable from internal access
- Detection delays mask the true scale of insider misuse
- Organizations still lack behavioral based insider risk programs
The Fortinet 2025 Insider Risk Report reinforces this point.
77 percent of organizations experienced insider driven data loss in the past 18 months, and only 14 percent feel confident in their insider risk tooling.
December did not contradict this trend. It highlighted it.
Conclusion
December 2025 will be remembered as the month when no insider attacks were detected, but insider risk conditions were impossible to ignore.
It was a month that validated the core thesis driving Secure From Inside:
Insider threat is not a person. It is a condition created by access, trust, and blind spots.
And December 2025 was full of them.
Sources
- Breached Company, The Year Cybersecurity Insiders Became Cybercriminals
https://breached.company/the-year-cybersecurity-insiders-became-cybercriminals-2025s-unprecedented-insider-threat-epidemic/ - Enginerds, December 7 to 14, 2025 Data Breaches
https://enginerds.com/insights/Cybersecurity/Data%20breaches/2025/12/15 - Fortinet, 2025 Insider Risk Report
https://www.fortinet.com/content/dam/fortinet/assets/reports/2025-insider-risk-report-ftnt.pdf
Leave a Reply