Directory traversal is an attack technique that manipulates file paths to escape the intended directory and reach other parts of the filesystem. In enterprise applications, it often becomes a privilege problem when a service accepts path input without constraining where that input can point.
Expanded Definition
Directory traversal is a file path manipulation technique that tries to move an application outside its intended directory boundary and into other filesystem locations. In NHI and application security work, the issue is not simply “bad input”; it is a trust failure in how a service resolves user-controlled or agent-controlled paths before granting file access. The most effective way to understand it is through the lens of path normalization, allowlisting, and execution context, because a path that looks harmless in one layer may resolve elsewhere after decoding or filesystem interpretation. Guidance across vendors varies on whether this belongs strictly to input validation, access control, or secure file handling, but the operational risk is the same: a path becomes a privilege escalation path when the application can read, write, or invoke files outside its intended scope. For baseline security planning, the NIST Cybersecurity Framework 2.0 is a useful external reference for mapping this to protected asset handling and access control discipline. The most common misapplication is assuming sanitising a string once is enough, which occurs when the application fails to canonicalise paths after decoding or symbolic-link resolution.
Examples and Use Cases
Implementing directory controls rigorously often introduces usability and compatibility constraints, requiring organisations to balance flexible file handling against strict path confinement.
- An upload feature accepts a filename from an AI agent or service account and writes it into a storage directory without canonical checks, allowing the request to escape into another folder.
- A document retrieval endpoint maps a path parameter directly to the filesystem, and an attacker uses traversal sequences to read configuration files or secret material.
- A batch job running with elevated service privileges processes file references from an integration partner, but the path is not constrained to a permitted root, creating cross-directory access.
- An internal tool trusts paths generated by automation and later resolves them after decoding, which can turn a benign-looking reference into an unintended filesystem target.
These patterns are closely related to broader NHI exposure described in Ultimate Guide to NHIs, especially where service accounts and automation have broad filesystem rights. For secure implementation patterns, teams often pair path validation with application-layer access controls and refer back to the control intent in NIST Cybersecurity Framework 2.0.
Why It Matters in NHI Security
Directory traversal becomes especially serious in NHI environments because non-human identities often run unattended, hold durable credentials, and interact with high-value files such as tokens, certificates, build artifacts, and configuration data. Once a service account can traverse outside its sandbox, the result is rarely limited to one file. It can expose secrets, alter automation inputs, or create a foothold for deeper compromise. NHIMG notes that 80% of identity breaches involved compromised non-human identities such as service accounts and API keys, which is why a file-path issue should be treated as an identity risk, not only a web input defect. The same governance gap appears when teams manage NHI access but overlook what those identities can reach on disk, in containers, or on shared hosts. That gap is reflected in the fact that only 5.7% of organisations have full visibility into their service accounts, according to Ultimate Guide to NHIs. Organisations typically encounter the consequence only after a file read, credential leak, or lateral movement event, at which point directory traversal becomes operationally unavoidable to address.
Standards & Framework Alignment
This section maps relevant standards and security frameworks to the operational risks and controls described in this guidance.
OWASP Non-Human Identity Top 10 address the attack and risk surface, while NIST CSF 2.0 and NIST Zero Trust (SP 800-207) set the governance and control requirements practitioners need to meet.
| Framework | Control / Reference | Relevance |
|---|---|---|
| OWASP Non-Human Identity Top 10 | NHI-02 | Path abuse often exposes or reaches secrets, a core NHI secret-management risk. |
| NIST CSF 2.0 | PR.AC-4 | Least-privilege access should limit what service identities can read or write on disk. |
| NIST Zero Trust (SP 800-207) | SC.L2-3 | Zero trust requires verifying every requested resource, including file paths. |
Constrain file access paths and verify secret locations are not reachable by untrusted input.
Related resources from NHI Mgmt Group
- Why do Active Directory service accounts complicate zero trust programs?
- How should security teams govern Active Directory service accounts?
- What is the difference between direct access and effective access in Active Directory?
- Why do Active Directory service accounts create more risk than their labels suggest?
Deepen Your Knowledge
Reviewed and updated by the NHIMG editorial team on June 24, 2026.
NHI Mgmt Group — the #1 independent authority on Non-Human Identity, IAM, and Agentic AI security. nhimg.org
