Full Report
TL;DR How to do NoSQL error-based injection
Analysis Summary
# Tool/Technique: NoSQL Error-Based Injection
## Overview
This technique describes novel approaches to exploiting NoSQL databases (specifically MongoDB syntax referenced in examples) vulnerable to injection, focusing on leveraging database error messages to exfiltrate data rapidly, as an alternative to slow character-by-character enumeration techniques.
## Technical Details
- Type: Technique (Injection Exploitation)
- Platform: NoSQL Databases (MongoDB syntax relevant)
- Capabilities: Data exfiltration via manipulated error messages (using `throw`), time delays (using `sleep`), and information gathering using regex matching.
- First Seen: Described as a potentially novel approach within the context of the article.
## MITRE ATT&CK Mapping
The core activity maps to probing and information gathering using SQL/NoSQL injection techniques.
- **TA0001 - Initial Access** (Indirectly, as injection exploits an entry point)
- T1190 - Exploit Public-Facing Application (If the injection point is exposed)
- **TA0010 - Exfiltration**
- T1048 - Exfiltration Over Alternative Protocol (Leveraging application error stream for data)
- **TA0009 - Collection**
- T1005 - Data from Local System (If data is retrieved server-side)
## Functionality
### Core Capabilities
* **Boolean/Time-Based (Enumeration):** Using conditions (`&&`, `||`) or `sleep()` within `$where` clauses to determine data character-by-character, which is noted as slow.
* Example Payload (Boolean): `admin' && this.password[0] == 'a' || 'a'=='b'`
* Example Payload (`$regex`): `"{"$regex":"^a*"}`
* **Error-Based Exfiltration (Fast Data Retrieval):** Exploiting the application's error message output to dump entire documents quickly. This requires the application to surface database errors.
* Payload using `$where`: `'; throw new Error(JSON.stringify(this));'` to dump the current document.
* When injecting into a document structure: `","username":{"$ne":""},"$where":"throw new Error(JSON.stringify(this))`
### Advanced Features
* **Sequential Document Dumping:** Using `if` statements within `$where` to selectively skip already exfiltrated documents, often by checking against previously extracted usernames or, preferably, by comparing the document's `_id` field sequentially.
* Payload using `_id` progression: `if (this._id>'66d5ef7d01c52a87f75e739c') {throw new Error(JSON.stringify(this))}`
* **Type Casting for Extraction:** Using `$expr` context operators like `$toInt` on a string field (e.g., `$username`) to force a database error that includes the field's value in the resulting error message.
* Payload using `$expr`: `"$expr": {"$toInt": ["$username"]}`
## Indicators of Compromise
Since this is an injection technique, IoCs are primarily payload-based.
- File Hashes: N/A
- File Names: N/A
- Registry Keys: N/A
- Network Indicators: N/A (The attack focuses on local database command execution and response manipulation)
- Behavioral Indicators:
- Application returning unexpected, verbose error messages containing sensitive data structures (like JSON representations of documents).
- Excessive database query failures or timeouts related to complex injection strings containing `throw`, `sleep`, or nested comparison logic.
## Associated Threat Actors
This summary does not identify specific threat actors, as it describes a general exploitation technique applicable to any user or actor that discovers a vulnerable NoSQL endpoint.
## Detection Methods
Detection focuses on recognizing the malicious structure within database query parameters.
- Signature-based detection: Signatures targeting keywords like `throw new Error`, `JSON.stringify(this)`, `$where`, `$regex`, and suspicious sequence continuation operators (`;`, `&&`, `||`) within input fields expected to contain simple data.
- Behavioral detection: Monitoring for application responses that frequently contain error messages rather than expected data, especially large, structured content within error strings.
- YARA rules: Rules could be developed to detect complex query strings containing structured JavaScript commands embedded in network traffic targeting NoSQL endpoint parameters.
## Mitigation Strategies
* **Prevention Measures:** Implement strict input validation and sanitation on all user-supplied data destined for NoSQL queries. Avoid interpolating raw user input directly into query constructors.
* **Hardening Recommendations:**
* **Least Privilege:** Ensure the application's database connection operates with the minimum necessary privileges.
* **Error Suppression:** Configure the NoSQL driver/server to suppress detailed database error messages from being returned to the client application layer. Use generic error handlers.
* **Use Parameterized Queries:** When available and feasible for the specific NoSQL database, use safe query construction methods that separate logic from data, although NoSQL often lacks true preparation in the same way as SQL.
* **Disable Dangerous Operators:** Where possible, configure the database environment to restrict or disable dangerous operators like `$where` or `$expr` in contexts accessible via external user input.
## Related Tools/Techniques
* NoSQL Boolean-Based Injection (Slower data extraction method)
* MongoDB Injection techniques generally.
* JavaScript injection methods in web applications.