Posts Tagged ‘server port’

How to query LDAP (Windows Domain Controller) directory entries from Linux – ldapsearch common searche examples

Tuesday, November 18th, 2014

Reading Time: 3minutes

If you have a hybrid network of Windows servers and computers in Active Directory (AD) Domain Names and Linux hosts hosting various Java / PHP / Python applications like many of the middle and big companies (organization) have, sooner or later you will have to deploy an application which uses some some user authentication from the Linux host to Windows Domain Controller, you will end up in need to be able to query the AD, which is using LDAP(Lightweight Directory Access Protocol) to store the AD user credentials and tons of other information important for proper Active Directory operations.

LDAP is a key industry standard for storing and accessing distributed directory information services over Internet Protocol (IP). LDAP is great for sharing of information about users, systems, networks, services, and applications throughout the network. The corporate world nowadays would have been impossible without LDAP.
As of time of writting latest RFC  (Resource for Comment) 4511 document describes industrial specification of LDAP version 3.0 and therefore this is the most often used and implemented version.

LDAP protocol supports generally following operations:

Adding, Delete, Bind (Authenticate to LDAP server), Delete Search and Compare, Modify and Modify DN(Distringuished Name)
Deleting recordsh

On Linux to retrieve / locate AD entries, there is ldapsearch  command which opens connection to LDAP host server port, with set username and password. ldapsearch tool makes its search based on a filter.

To have make and modify queries in LDAP from GNU / Linux you will have to have installed ldap-utils on Debian, i.e.:

apt-get –yes install ldap-utils

to have ldapseach, ldapmodify, ldapsearch ldappasswd on CentOS / Redhat Linux, you need openldap-clients.x86_64

yum -y install openldap-clients.x86_64

Returned result from ldapsearch clients will be returned in LDIF format (LDAP Data Interchange format).

ldapsearch basic format is like thsi:

ldapsearch [optional_options] [optional_search_filter] [optional_list_of_attributes]

ldapsearch could query (LDAP – ADs) in unencrypted form simple LDAP, encrypted form with SSL certificate (LDAPs) or through LDAP with STARTTLS.
Logically most organizations nowadays are using LDAPs, as it offers the highest level of security. Unencrypted LDAP servers listen usually on
port 389, LDAPs communicates on port 636 once an SSL handshake is made between client and server and LDAP with STARTTLS communicates on standard port 389.

Here is 3 examples of common  ldapsearch queries

1. Return all entries in LDAP server

ldapsearch -D "cn=directory manager" -w secret -p 389 -h -b "dc=your-organization,dc=com" -s sub "(objectclass=*)"

"objectclass=*" is a serch filter matching all entries in the directory (time and size limits on output limit set for the server will take affect)

2. Searching the Root DSE Entry

root DSE is special entry containing list of all suffixes supported by local Directory Server. Getting root DSE is done with  base of "", a search scope of base, and a filter of "objectclass=*"

ldapsearch -D "cn=directory manager" -w secret_pass -p 389 -h  -b "dc=your-organization,dc=com" -s sub "cn=babs jensen"


3. Searching Directory Server Schema Entry

LDAP server stores all directory server schema in special entry cn=schema.
schema entry contains information on every object class and attribute defined for the Directory Server. Command to searches  contents of the cn=schema entryis:

ldapsearch -D "cn=directory manager" -w secret_pass -p 389 -h -b "cn=schema" -s base "objectclass=*"

4. Check whether cn=My-Account1 account is working and enabled

ldapsearch -H ldaps:// -b o=my-org,c=bg -s sub -D cn=My-Account1,ou=users,ou=ABC,o=my-org,c=ABC -W '(&(cn=My-Acount1)(objectclass=my-org-Account))'

5. check all members of cn=MY_ADMINISTRATION


ldapsearch -H ldaps:// -b o=my-org,c=bg -s sub -D cn=My-Account1,ou=users,ou=ABC,o=my-org,c=ABC -W '(&(cn=MY_ADMINISTRATION)(member=*))'


6. check all members of all groups belonging to user

ldapsearch -H ldaps:// -b ou=ABC,ou=ABC1,ou=ABC2,ou=groups,ou=ABC,o=my-org,c=ABC -s sub -D cn=My-Account1,ou=users,ou=ABC,o=my-org,c=ABC -W '(cn=*)'

Whether ldapsearch queries are to be common and scripted or just for simplification of readability of query to LDAP it is useful to useLDAP_BASEDN – a query search base. By setting search base you can further omit in query -b

export LDAP_BASEDN="dc=your-organization,dc=com"
ldapsearch -D "cn=directory manager" -w secret_pass -p 389 -h "cn=labs jordan"

In Linux LDAP's open-source implementation is called OpenLDAP.
On Linux LDAPprotocol can be easily integrated / used in combination with FTP servers (such as proftpd), DNS servers, Mail Servers (Courier), Samba servers, Radius (IP Telephony), sudo, as well as most programming languages such as PHP, Python etc.

ZenMap Nmap multi platform Graphical frontend for checking port security

Saturday, June 15th, 2013

Reading Time: 2minutes

graphic program to scan remote network server port security on GNU Linux and Windows ZenMap

Recently I wrote little article with some examples for scanning server port security with Nmap. I forgot to mention in the article that there is also Nmap frontend GUI program called ZenMap. ZenMap port is available for both Windows and Linux. In Debian, Ubuntu, Mint and other debian derivative distributions ZenMap is available from standard package repositories;

 noah:~# apt-cache show zenmap|grep -i description -A 3

Description-en: The Network Mapper Front End
 Zenmap is an Nmap frontend. It is meant to be useful for advanced users
 and to make Nmap easy to use by beginners. It was originally derived
 from Umit, an Nmap GUI created as part of the Google Summer of Code.
Description-md5: 4e4e4c6aeaa4441484054473e97b7168
Tag: implemented-in::python, interface::x11, network::scanner, role::program,
 uitoolkit::gtk, use::scanning, x11::application
Section: net

To install  ZenMap on Debian / Ubuntu Linux:

noah:~# apt-get install --yes zenmap

In Fedora, CentOS and other RPM based Linux-es to install ZenMap run:

noah:~# yum -y install nmap-frontend nmap

To use Nmap's Frontend full functionality, you have to run it as (root) superuser:

hipo@noah:~$ sudo su
[sudo] password for hipo:
noah:~# zenmap

Zenmap saves, a lot of time as there is no need to  remember Nmap's arguments or run few Nmap scans until you get essential information for remote scanned machine.
It automatically gives details on Remote server running services (fingerprint)

Zenmap remote server security services scan with services software version

Very useful report it makes as well is network (and host) topology diagram,

network scanner remote host Linux Windows toplogy guess ZenMap screenshot

ZenMap is just Nmap frontend and under the GUI it does use Nmap with various arguments to do produce scan results. In Nmap Output tab, you can see a lot of verbose info.

Zenmap Linux Windows GUI port scanne nmap output tab screen Debian / Ubuntu Linux

Happy scanning 🙂