Insecure APIs create risk because they connect identity, cloud services, mobile apps, and vehicle functions in one control plane. If authentication or authorization fails, an attacker can pivot from a simple identifier to remote commands such as unlock, start, or location tracking. That turns a data flaw into a physical safety issue and can also expose broader dealership and customer systems.
Why insecure APIs become a vehicle security problem, not just an IT problem
Connected vehicles are built around APIs that let mobile apps, cloud services, dealers, and in-vehicle systems exchange commands and status. If those APIs are weak, the flaw is not limited to bad data handling. It can expose functions that affect the vehicle itself, which is why an authentication or authorization failure can become a real-world safety issue.
The key issue is that APIs often sit at the boundary between digital identity and physical action. Once an attacker can abuse a trusted API path, they may be able to reach remote unlock, remote start, location queries, charging controls, or other functions that change the vehicle’s state. That makes API security a control-plane problem with both cyber and physical consequences.
How the attack path moves from API weakness to physical impact
An insecure API can fail in several ways, but the most dangerous pattern is broken trust in who is calling the API and what that caller is allowed to do. In practice, that may mean weak authentication, broken object-level authorization, overbroad tokens, exposed endpoints, or poor inventory of undocumented interfaces. The attacker does not need to “hack the car” in the traditional sense if they can borrow legitimate API pathways.
That matters because vehicle ecosystems are interconnected. A flaw in a consumer app API or backend service can give access to a vehicle account, then to fleet, dealer, or support tooling, and then to actions that affect one or many vehicles. The risk is not just data exposure. It is command exposure, and the difference is operationally significant when the command changes locks, movement, or location tracking. For API-specific control patterns, OWASP API Security Top 10 is a useful reference point for broken authorization and related API failures.
In connected-vehicle environments, those failures are amplified by the fact that APIs usually bridge multiple trust zones. Mobile apps, cloud identity services, telematics platforms, and OEM backends often share assumptions about session state, token scope, and object ownership. When those assumptions are wrong, the same defect can affect many vehicles, many users, or many dealer accounts at once.
Why the same flaw can create cyber risk and physical risk at the same time
Cyber risk appears first because the attacker is abusing a digital trust relationship. But once that trust relationship reaches a control function, the outcome is no longer purely digital. A stolen token, a guessed identifier, or a broken authorization check can lead to unauthorized unlocks, tracking, or remote control. In a vehicle context, that becomes a safety and privacy problem as well as an access-control failure.
There is also a broader blast-radius issue. Vehicle APIs often share infrastructure with customer portals, dealer services, billing, telematics, and support workflows. A weakness in one layer can expose adjacent systems or let an attacker move laterally from vehicle actions into broader account or service abuse. That is why API security in this sector must be treated as part of operational resilience, not just application hardening.
For teams that want a broader view of the exploitation ecosystem around credentials, secrets, and lateral movement, The 52 NHI Breaches Report is a useful reminder that stolen or misused machine-facing access often becomes the bridge from cyber compromise to downstream impact. For threat analysis and campaign tracking, MITRE ATT&CK Enterprise Matrix remains the clearest way to reason about credential access, lateral movement, and privilege escalation.
Risk and Threat Considerations
Connected vehicles increase the stakes of API failure because the same trust path can govern both account data and physical functions. A single authorization defect can therefore produce privacy exposure, account abuse, fleet-wide misuse, and real-world safety consequences, especially when tokens or identifiers are reusable across services.
Failure mechanism: Attackers exploit weak authentication, broken object-level authorization, exposed tokens, or poor endpoint inventory to issue legitimate-looking API calls that reach vehicle functions or adjacent backend systems.
Impact: The outcome can include unauthorized unlock or start commands, location disclosure, account takeover, broader dealership or customer-system compromise, and physical risk if vehicle controls are triggered without the owner’s intent.
Standards & Framework Alignment
This section maps relevant standards and security frameworks to the operational risks and controls described in this guidance.
OWASP API Security Top 10 and MITRE ATT&CK address the attack and risk surface, while CIS Controls v8 sets the governance and control requirements practitioners need to meet.
| Framework | Control / Reference | Relevance |
|---|---|---|
| OWASP API Security Top 10 | API1 — Broken Object Level Authorization | Connected-vehicle APIs often fail through object access errors that expose vehicle-specific actions. |
| API2 — Broken Authentication | Unauthorized vehicle actions often begin with weak or reused API authentication. | |
| API5 — Broken Function Level Authorization | Remote commands become dangerous when callers can invoke functions they should not access. | |
| Recommendation — Enforce object ownership checks on every vehicle and account API request. Require strong authentication and reject weak or replayable API credentials. Authorize each sensitive vehicle function server-side before executing it. | ||
| MITRE ATT&CK | T1078 — Valid Accounts | API abuse in vehicle ecosystems often uses legitimate credentials or tokens after compromise. |
| Recommendation — Hunt for misuse of valid accounts and token replay across vehicle services. | ||
| CIS Controls v8 | CIS-6 — Access Control Management | Vehicle command APIs depend on tightly managed access rights and endpoint inventory. |
| Recommendation — Restrict and review access to all commands that can affect vehicle state. | ||
Practitioner Guidance
What to prioritise: Treat the API as a safety-relevant control surface, not only an application interface. The first question is whether each endpoint can affect a vehicle state, a user account, or another privileged backend action, because those endpoints deserve the strongest authentication and authorization scrutiny.
What to verify: Confirm that object ownership, token scope, and command authorization are enforced independently on the server side for every sensitive function. Do not trust mobile app logic, client-side checks, or “hidden” endpoints to protect commands that can change a vehicle’s state.
Practitioner takeaway: If an API can move from identity to action, the security objective is not just preventing data leakage. It is preventing unauthorized command execution before that command reaches the vehicle or any system that can control it.
Related resources from NHI Mgmt Group
- Why do connected vehicles create machine identity risk?
- Why do telematics APIs create physical risk, not just data risk?
- Why do companion apps and backend APIs create such a large risk in connected cars?
- Why do connected vehicles and physical AI systems create blind spots for XDR and SOC operations?
Deepen Your Knowledge
Reviewed and updated by the NHIMG editorial team on September 29, 2026.
NHI Mgmt Group — the #1 independent authority on Non-Human Identity, IAM, and Agentic AI security. nhimg.org
