MongoDB CSFLE and Encryption at Rest vs Ubiq Security

This page compares Ubiq Security’s identity-driven data protection platform with MongoDB’s native data security controls. Specifically Client-Side Field Level Encryption (CSFLE) and MongoDB Encryption at Rest (WiredTiger Encrypted Storage Engine). The focus is real-world effectiveness against insider threats, stolen credentials, and runtime misuse. Key dimensions include insider threat protection, defense against credential compromise, access control granularity, runtime enforcement (data in use), integration effort, performance impact, data coverage beyond the database, key management, and compatibility with enterprise IAM/Zero Trust.

Comparison Matrix

The following matrix compares three approaches to securing sensitive data in MongoDB environments. It evaluates effectiveness against insider threats, compromised credentials, and operational constraints.

  • Ubiq Security = Ubiq’s identity-driven encryption, tokenization, and masking platform (application/driver integration assumed).
  • MongoDB CSFLE = Client-Side Field Level Encryption; the server stores only ciphertext. Enterprise/Atlas only.
  • MongoDB Encryption at Rest = Storage-level (on-disk) encryption via the WiredTiger Encrypted Storage Engine. Enterprise/Atlas only.

Note: CSFLE and the Encrypted Storage Engine are MongoDB Enterprise/Atlas features. CSFLE’s automatic mode is not available in Community Edition.

Summary Matrix

Security DimensionUbiq SecurityMongoDB CSFLEMongoDB Encryption at Rest
Insider Threat ProtectionHigh – Field-level encryption bound to identity; DB/cloud admins cannot view plaintext without IAM-governed approval.High – Server stores only ciphertext for protected fields; DBAs see ciphertext.Low – Protects only on disk; once running, privileged users can query plaintext.
Defense Against Stolen CredentialsHigh – Requires valid Ubiq and IAM credentials; a DB login alone cannot decrypt protected fields.Medium – DB-only compromise reveals ciphertext; if app/KMS keys are also stolen, attacker can decrypt.Low – Any valid DB credential returns plaintext; decryption is transparent during operation.
Access Control GranularityHigh – Per-field, per-identity encryption/tokenization; least privilege via IAM; different users can see masked vs plaintext.Medium – Field-level, but key-holder sees full plaintext; not identity-aware by default.Low – Database/volume-level; no per-field or per-user differentiation once authorized.
Runtime Enforcement (Data in Use)High – External policy check on each decrypt; identity/context verified every time (Zero Trust).Medium – Client decrypts if it has the key; no per-access policy check beyond app logic.Low – Decryption is automatic for any permitted query; no extra runtime checks.
Integration EffortMedium – Add Ubiq SDK/UDF calls for selected fields; no MongoDB engine changes.High – Define encryption schema; use CSFLE-capable drivers; set up key vault/KMS; maintain mongocryptd in auto mode. Enterprise/Atlas only.Low – Enable at rest in Enterprise/Atlas; transparent to apps.
Performance ImpactLow – Microseconds to milliseconds per protected value; limited to sensitive fields.Medium – Client CPU and larger payloads; limited server-side querying on encrypted fields.Low – Few-percent I/O overhead; largely invisible to queries.
Data CoverageHigh – Protects MongoDB fields and data beyond the DB (files, pipelines); encryption “travels” with data.Medium – Protects specific MongoDB fields; exports/other systems need separate controls.High (at rest) – Encrypts DB files/backups; not data in use or exported data.
Key ManagementHigh – Externalized, FIPS/HSM-backed or BYOK; per-field/per-dataset keys; identity-gated key release.Medium – External KMS + key vault; solid separation but management overhead and coarse per-key scopes common.Medium – Master key via KMIP/KMS/keyfile; coarse granularity (DB/cluster).
IAM CompatibilityHigh – Native integration with enterprise IdPs (Okta, Entra ID); decryption governed by identity/policy, fully auditable.Low – Not identity-aware; any client with the key decrypts; IAM linkage must be app-implemented.Low – DB-centric; no identity-aware decryption.

Detailed Matrix

Security DimensionUbiq Security Platform (Identity-Driven Data Protection)MongoDB CSFLE (Enterprise/Atlas)MongoDB Encryption at Rest (Storage-Level)
Protection Against Internal Threats (malicious DBA/cloud insider)High. Sensitive fields remain encrypted unless an authorized identity is validated by Ubiq. Keys and crypto live outside the DB, so dumping collections or memory yields ciphertext. DB/cloud admins cannot bypass IAM-governed decryption.High. Server never sees plaintext for encrypted fields; DBAs see ciphertext. Protection assumes the application/KMS aren’t also compromised.Low. Encrypts only on disk. Once running, the engine decrypts for any permitted query. Privileged users can read plaintext via normal DB access.
Protection Against External Credential Compromise (stolen DB/app creds)High. A stolen DB login is insufficient; attacker also needs Ubiq credentials and must pass policy checks. Protected fields remain unreadable if only DB creds are stolen.Medium. DB-only compromise yields ciphertext; if the attacker also compromises the app or KMS keys, they can decrypt.Low. Stolen DB creds act as legitimate access; the engine decrypts and returns plaintext.
Data in Transit / In MemoryData is encrypted before storage and stays encrypted over the wire and at rest; plaintext exists only in the app at point of use. TLS still recommended.Encrypted values are produced in the client; the server stores/transmits ciphertext. Plaintext lives only in the client process.Only on-disk encryption; data in memory is plaintext; use TLS separately for in-transit encryption.
Granularity & FlexibilityPer-field/per-record, with optional tokenization/masking and format-preserving patterns for usability. Policies can differ by identity/role.Field-level within MongoDB. Entire field values are encrypted; per-user differences require separate keys and custom logic.Database/volume-level; all data at rest is encrypted uniformly; no field-level differentiation.
Impact on Querying & IndexingEncrypted fields aren’t natively queryable by the DB (except deterministic equality patterns you design for). Common patterns: deterministic encryption for exact matches; app-side filtering for others.Equality queries supported on deterministically encrypted fields; most range/text/partial queries on encrypted fields are limited or require specialized indexes/enclaves.Full query capability (range, text, sort, aggregates) — because the DB decrypts before query execution.
Integration Effort & PerformanceModerate app changes (SDK/UDF calls); no DB engine changes. Overhead microseconds–milliseconds per protected field; affects sensitive fields only.Significant app/driver/KMS setup; define encryption schemas; manage key vault; mongocryptd in auto mode. Client-side CPU and larger payloads add medium overhead.Minimal app impact; enable at rest in Enterprise/Atlas; low I/O overhead; periodic key rotation via KMIP/KMS.
Data Coverage Beyond the DBBroad: applies uniformly across databases, files, pipelines, and exports — encryption “travels” with data until policy-approved decryption.Limited to MongoDB fields; exports or other systems require separate encryption.At rest only within the MongoDB deployment; downstream targets need their own controls.
Key Management & Separation of DutiesExternalized KMS/HSM (or BYOK). Per-dataset/field keys; identity-gated release; centralized rotation/revocation. DBAs never handle keys.External KMS (AWS/Azure/GCP/HSM) + key vault collection for data keys. Solid separation from DB, but operational overhead (key lifecycles, KMS perms, multi-key design).Master key via KMIP/KMS/keyfile; coarse scope (DB/cluster). DB retrieves/unwraps data keys at startup; rotation is periodic and coarser-grained.
Enterprise IAM / Zero TrustNative integration with IdPs (Okta, Entra ID). Decrypt checks are identity- and context-aware; revoking IAM roles immediately blocks decryption. Full identity-linked audit trail.Not identity-aware. CSFLE decrypts for any client with the key; IAM must be enforced at the app layer.Not identity-aware. DB roles govern access; decryption is transparent and not tied to external identity policies.

Explanatory Notes and Key Insights

Encryption at Rest vs Runtime Threats
MongoDB’s Encrypted Storage Engine protects data at rest by encrypting database files and backups using AES-256, mitigating risks of physical media theft or unauthorized access to raw files. However, once the database is online, any authorized query or session can read plaintext — encryption is transparent to the DB process and all privileged users. This means at-rest encryption satisfies compliance (HIPAA, PCI-DSS, etc.) but offers no runtime protection against insider misuse or credential theft.
By contrast, Client-Side Field Level Encryption (CSFLE) and Ubiq both secure data in use by ensuring the server never handles plaintext values. Ubiq extends this model beyond MongoDB by encrypting data before storage and requiring external identity-based policy validation for every decryption event, even at runtime. The result is continuous protection against both disk-level and live threats.

Governance vs Encryption Granularity
MongoDB’s encryption capabilities differ significantly in scope. The Encrypted Storage Engine provides coarse-grained encryption at the database or volume level — all data is protected equally on disk, with no per-field or per-user differentiation. CSFLE introduces finer granularity by encrypting individual fields or subsets of documents, ensuring the database and DBAs cannot view protected fields. However, it lacks governance context — any client with access to the key can decrypt the field, regardless of user role or purpose.
Ubiq combines fine-grained, field-level protection with centralized governance. Encryption and decryption privileges are enforced through identity policies within the enterprise IAM, enabling true least-privilege access. Multiple users can query the same data but receive different results (masked vs plaintext) based on policy, which MongoDB’s native tools cannot natively enforce.

Runtime and Context Enforcement
MongoDB’s built-in security mechanisms do not include runtime context evaluation. Once authenticated, a session remains trusted until it ends, and decryption occurs automatically (in the case of at-rest encryption) or within the client driver (for CSFLE). CSFLE’s enforcement stops at the application level — if the driver holds the key, all queries from that app context decrypt automatically.
Ubiq introduces continuous runtime enforcement aligned with Zero Trust principles. Each decrypt request triggers a real-time policy check against identity and context — such as user group, device, environment, or time. If conditions change mid-session, access is revoked immediately, and further decryption attempts fail. MongoDB’s model relies on static trust, whereas Ubiq enforces dynamic verification throughout data use.

Credential Compromise and Kill Switch
A compromised MongoDB credential (database user, IAM role, or API key) can allow an attacker to query plaintext data, as the database automatically decrypts content for any valid session. CSFLE mitigates this partially by requiring access to both the database and the KMS-stored key to decrypt protected fields, but if attackers compromise the application or its key management credentials, they can still retrieve plaintext.
Ubiq adds an additional control layer: both authentication and decryption are gated through IAM. Even if an attacker steals a database or application credential, decryption requests to Ubiq’s service will fail without valid identity context. Administrators can also instantly disable a user, role, or dataset policy — immediately halting decryption, even mid-session. This “fine-grained kill switch” minimizes breach impact and provides a second line of defense absent from MongoDB’s built-in architecture.

Integration and Performance
The Encrypted Storage Engine is straightforward to enable (MongoDB Enterprise/Atlas) and introduces negligible performance impact since encryption happens transparently at the storage layer. However, it is limited to baseline compliance and offers no control over data once queried.
CSFLE provides stronger data isolation but with more operational effort — developers must define encryption schemas, configure key vaults, use supported drivers, and manage KMS integrations. It can also affect query performance: equality searches are supported only for deterministically encrypted fields, while range or text searches are not natively supported without advanced features like Queryable Encryption (Enterprise/Atlas only).
Ubiq sits between these extremes — it requires light SDK or UDF integration at the app layer but centralizes encryption logic and policy enforcement outside the database. Performance impact is minimal (microseconds to milliseconds per field) since only sensitive data is encrypted and cryptographic operations are optimized in native code. This model delivers stronger protection without the extensive schema changes or driver complexity of CSFLE.

Key Management and Trust Separation
MongoDB’s storage encryption uses a master key — managed via a KMIP-compatible KMS or key file — to encrypt database files. While it supports external KMS integration, the database automatically uses the key once loaded, meaning privileged users or processes with system access can decrypt data. CSFLE separates keys from the database, storing data encryption keys (DEKs) in a key vault collection and wrapping them with a master key in an external KMS (e.g., AWS KMS, Azure Key Vault, or GCP KMS). This separation improves security but still ties trust to application-level key usage and configuration.
Ubiq externalizes key management entirely and binds key release to identity-based policies. Keys are stored and rotated within a FIPS-validated service or customer-managed HSM/KMS, and the database never holds or uses them directly. DBAs and system administrators cannot retrieve or use encryption keys independently, enforcing complete separation of duties. Even if the MongoDB instance or host OS is compromised, the attacker cannot decrypt data without breaching both IAM and Ubiq’s key authority — a combination that creates full cryptographic isolation between data, infrastructure, and identity.

Summary

MongoDB’s native encryption addresses different layers: Encryption at Rest satisfies baseline compliance and defends against offline theft but leaves live data visible to any permitted user; CSFLE keeps sensitive fields encrypted from the server and DBAs, significantly improving confidentiality but requiring application/driver/KMS integration and accepting query limitations. Ubiq extends client-side protection with identity-driven, runtime policy checks and unified key management across systems, keeping data encrypted until a verified identity is allowed to decrypt, even as data inevitably moves beyond MongoDB.


References


© 2025 Ubiq Security, Inc. All rights reserved.