Nosql-Sicherheit: Risiken, NoSQL-Injection-Angriffe und Abwehrmaßnahmen verstehen

Nosql encompasses a broad set of non-relational database technologies used widely in modern applications to support flexible schemas and horizontal scalability. Despite their advantages, NoSQL systems are not inherently secure by design—developers must understand NoSQL injection vulnerabilities, how attackers can exploit them, and how to systematically defend against them. This article provides a deep technical exploration for security engineers, including real threat scenarios, preventative strategies, code examples, and references to high-impact CVEs.

What NoSQL Is and Why It Matters for Security

NoSQL (short for “Not Only SQL” or “non-relational SQL”) databases abandon traditional relational models in favor of flexible data models such as key-value stores, document stores, column-family, and graph databases. Popular implementations include MongoDB, CouchDB, Redis, Cassandraund Neo4j. These systems provide scalability and schema agility, but they also introduce new query semantics and security pitfalls unfamiliar to engineers accustomed to SQL systems. vaadata.com

Unlike SQL, each NoSQL system has its own query language (e.g., JSON-based queries in MongoDB) and different operator semantics. While this diversity improves flexibility, it also results in unique injection attack vectors because user inputs are often interpolated into database queries without proper sanitization. vaadata.com

NoSQL Injection: What It Is and When It Happens

At its core, a NoSQL injection occurs when an attacker sends crafted input that alters the intended structure of a database query. Unlike SQL injection’s traditional text-based grammar, NoSQL injection often abuses JSON payloads or query operators wie zum Beispiel $ne, $gt, $lt, $regex, oder $where to manipulate logic. vaadata.com

Real-World Examples and Scenarios

Consider a typical Node.js + MongoDB authentication snippet where developers directly use client input to query credentials:

javascript

// Vulnerable authentication

db.users.find({

email: req.body.email,

password: req.body.password

});

An attacker could supply a value like:

json

{ "email": { "$ne": null }, "password": { "$ne": null } }

This query returns documents where the email is nicht null AND the password is nicht null, effectively bypassing authentication without knowing valid credentials. vaadata.com

Typical NoSQL Databases and Where Injection Occurs

Each model poses a different risk profile because of query language differences. For example, MongoDB allows queries using operators like $where that execute arbitrary JavaScript, increasing attack surface. InfoQ

High-Impact CVE Examples Linked to NoSQL Injection

While NoSQL injection tends to be underreported compared to SQL injection, documented security issues show that they are very real. For instance:

• CVE-2024-48573: A NoSQL injection in Aquila CMS allowed an attacker to reset account passwords because user-provided filters were not sanitized, enabling malicious operator injection. vaadata.com

Other reported bugs (e.g., issues with $where misuse in ODMs) reinforce that injection vectors may arise not only from application code but also from insecure library or schema handling. Bright Security

How NoSQL Injection Can Be Exploited

NoSQL injection attacks vary in impact depending on the database and security posture. They can be used to:

• Bypass authentication logic
• Extract sensitive records
• Modify or delete critical data
• Elevate privileges
• Trigger secondary application vulnerabilities (e.g., RCE via JavaScript execution)

Example: Authentication Bypass

javascript

// Attacker payload modifies query logic

db.users.find({

email: { $regex: ".*" },*

*password: { $regex: ".*" }

});

This matches any credentials because .* is a regex that matches everything—effectively bypassing login checks. vaadata.com

Detecting NoSQL Injection

Testing for NoSQL injection involves:

• Identifying points where user input is passed directly into database queries
• Fuzzing user parameters with operator keys like $ne, $gt, $lt
• Observing application behavior changes (e.g., authentication bypass, query result differences)
• Testing via automated scanners and manual pentesting techniques Indusface

Engineers often rely on both manual probes and automated tools to simulate malicious payloads.

Defensive Strategies: Input Validation and Query Hardening

The essence of defending against NoSQL injection is treating all user input as untrusted and eliminating any opportunity for that input to alter query structure.

Bewährte Praktiken

1. Input Validation & Whitelisting Allow only expected fields and data types. Reject or sanitize special characters and JSON operators that could alter query logic. Indusface
2. Parameterized/Prepared Queries Though NoSQL lacks universal prepared statements, many drivers support safer query builders that avoid string concatenation.
3. Schema Validation Use document schemas or model validation (e.g., Mongoose schemas) to enforce expected input shapes.
4. Disabling Dangerous Operators Disable evaluation of $where, $eval, or JavaScript execution in database configs. Indusface
5. Least Privilege Policies Restrict database user permissions so that even if an injection occurs, the blast radius of operations (reads/writes) is limited.
6. Protokollierung und Überwachung Log unusual query patterns to detect injection attempts and trigger alerts.

Code Examples: Attack vs Defense Patterns

Below are practical code snippets illustrating both exploitation and mitigation.

MongoDB Authentication Bypass Attack

javascript

// Unsafe: direct user input in query

db.users.find({

username: req.body.user,

password: req.body.pass

});

Defensive Pattern: Whitelist and Cast Inputs

javascript

const userInput = {

user: String(req.body.user || ""),

pass: String(req.body.pass || "")

};

db.users.find({ username: userInput.user, password: userInput.pass });

Regex Abuse in Queries

Angriffs-Nutzlast:

json

{ "name": { "$regex": ".*" } }

Defense (Disallow Regex):

javascript

if (!/^[A-Za-z0-9_]+$/.test(req.body.name)) {

throw new Error("Invalid characters");

}

Preventing JavaScript Execution in MongoDB

Unsafe:

javascript

db.users.find({ $where: "this.age > 25" });

Safe Configuration:

bash

# mongod.conf

setParameter:

javascriptEnabled: false

Parameterized Query Simulation

Unsafe:

javascript

collection.find({ filter: JSON.parse(req.body.filter) });

Safe Parsing with Sanitization Library

javascript

const sanitize = require('mongo-sanitize');

const filter = sanitize(req.body.filter);

collection.find(filter);

REST API Input Filtering

Verwundbar:

javascript

app.post("/search", (req, res) =>

db.collection("items").find(req.body).toArray()

);

Hardened:

javascript

const allowedFields = ["category", "price"];

const query = {};

allowedFields.forEach(f => {

if (req.body[f]) query[f] = req.body[f];

});

db.collection("items").find(query).toArray();

Penligent and Automated NoSQL Security Testing

In complex applications, manually identifying every injection vector across APIs, dynamic inputs, and microservices is often untenable. Sträflich, an AI-driven penetration testing platform, helps security teams by:

• Automatically generating and injecting crafted NoSQL payloads to probe for vulnerabilities
• Correlating query patterns with high-risk behaviors
• Integrating with CI/CD pipelines to catch regressions early
• Producing prioritized reports aligned with OWASP and CWE classifications

This approach complements traditional SAST/DAST with context-aware analysis, especially useful for dynamic NoSQL query languages where static rules alone may be insufficient.

Conclusion: NoSQL Isn’t Immune—Design Securely

NoSQL databases offer scalability and flexibility, but they are not immune to injection risks simply because they use different syntax. Injection flaws in NoSQL can bypass authentication, expose data, or allow unauthorized operations when input is improperly handled. By combining strong input validation, schema enforcement, secure driver usage, and automated testing (including AI-assisted platforms like Penligent), engineers can significantly reduce exposure to nosql injection attacks.