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Saturday, February 21, 2015

Cracking WEP Encryption with Airmon-ng / Airodump-ng / Aircrack-ng

WEP has been broken for years... Why are people still using it?

Intro


This weekend it is both cold and snowy in my area. I'm in the process of upgrading VMs and decided to upgrade my Backtrack instance to Kali Linux 1.1.0. As part of this process, I needed to test my Wireless Adapter's compatibility. I plugged it in and fired up airmon-ng to see if monitor mode was working properly. To my surprise, I noted at least (2) WEP access points, (1) WPA, and the remaining were WPA2. Additionally, only (2) AP were not broadcasting their SSID. A hidden SSIDs can be revealed in about 5 minutes worth of work but at least make an attacker work for it.



As an exercise, I did the following to my network:
  • Enabled broadcast of my SSID
  • Switched to WEP
  • Attempted to discover my WEP Wireless Key/Password

History

In 2003, the Wi-Fi Alliance declared that WEP was deprecated. It was replaced by Wi-Fi Protected Access (WPA). In 2004, WPA was replaced/upgraded to WPA2 (TKIP versus AES/CCMP cipher). WEP is based on key that concatenates a 24-bit initialization vector(IV) to traffic. Using a 24-bit IV, there is a 50% probability the same IV will repeat after 5000 packets. This weakness coupled with the fact that wireless is easily monitored/captured.... breaking WEP is pretty easy. It will take me longer to type this blog post, than it will to demonstrate the weakness....


Attack Details

This can be accomplished with a number of automated tools GUI tools (fern-wifi-cracker, kismet, WEPCrackGUI, etc...). Using a GUI is probably the easiest way to test this... however... that would be a 2 step blog entry... not fully exercise my WIFI driver tests... and be no fun :-)

Step 0) Change MAC address to hide your identity. 

I marked this step 0, because ideally you are attacking yourself and you shouldn't need to do this step. It is not ethical to attack your neighbors or other networks..... even if they are using technology from 2003. Regardless, I needed to test if my WIFI card supported MAC changing.

To change your MAC address you need to shutdown the wireless interface and change the address (we will bring it up in a later step).

Down interface command: ifconfig wlan0 down
Change MAC command: macchanger --mac 00:08:25:11:A3:D7 wlan0

You can pick whatever MAC address you want to use. The above assumes your Wireless Card is wlan0. Here is example verifying the MAC change: (I chose ACME Packet as my faked vendor)


Step 1) Bring up Interface and turn on "monitor mode"


Bring up interface:  ifconfig wlan0 up
Enable Monitor Mode: airmon-ng start wlan0

Verify Monitoring: iwconfig

 

Step 2) Search Target Info



Using airdump-ng on the monitored interface, we can see all of the networks visible to our wireless card.

Start airodump-ng: airodump-ng mon0


Below is a capture of the surrounding "wireless pollution" with my network set to WEP.



You can see that some of my neighbors are telegraphing paths of attack:
  • Golf Themes (ringworld, pingworld) 
  • Music/Band Names (Rush, Old Gray)
  • Conservation (Green Giraffe)
  • Probable Default Router Config - F8:E4:FB / 00:26:B8 ActionTec routers with (5) Char Names 
  • Probable Default Password - NETGEAR-Guest 

Step 3) Start Logging Target Traffic


I've selected my network (POMAC) which is on Channel 1 with BSSID CC:35:40:B8:AC:7F. I'm going to log the traffic to traffic set name "POMAC

Logging Command:  airodump-ng -c 1 -w POMAC --bssid CC:35:40:B8:AC:7F mon0

Screenshot ommited... it looks like the previous step, but filtered to only one BSSID.

LEAVE THIS WINDOW RUNNING.

Step 4) Spoof Association with the Access point.

We need to have an associated MAC address with the access point to perform injections on it. The fake authentication will associate us with the access point. We need to have an associated MAC address for the next step.

To do this we will use aireplay-ng. We will use the BSSID (CC:35:40:B8:AC:7F), our MAC address (00:08:25:11:A3:D7) and the ESSID (i.e. network Name) POMAC. This may take a few seconds. You might get multiple successful "Authentications" before you successfully "Associate".

In a NEW Terminal window:

Command: aireplay-ng -1 0 -a CC:35:40:B8:AC:7F -h 00:11:22:33:44:55 -e POMAC mon0

Below is a capture of this command execution:



Step 5) ARP Replays to generate new initialization vectors (IVs)

We are going to use ARP Replays to generate new initialization vectors (IVs). The program listens for an ARP packet then retransmits it back to the access point. This, in turn, causes the access point to repeat the ARP packet with a new IV. Remember from above, statistically, after 5000 messages an IV will repeat allowing us to crack the key.

In the window used in step 4, we will use the BSSID (CC:35:40:B8:AC:7F) and our MAC address (00:08:25:11:A3:D7). This step will cause a bit of a Denial of Service on the access point, as it is being flooded with ARP packets. Since this AP is mine.... I'm not worried about that....

You will need to monitor the airodump-ng window from Step 3. You want the #DATA column to reach something above 5000 before ending aireplay-ng command below with a control-c. (10000+ messages is recommend.)

Command: aireplay-ng -3 -b CC:35:40:B8:AC:7F -h 00:08:25:11:A3:D7 mon0

Here is what the ARP Replay will look like:



Step 6) Process your captured data to reveal the key

After reaching 5000 (10000 recommended) in the #DATA column of the airodump-ng window, you can kill the ARP Replay window using control-c. You can then also kill the airodump-ng window. At this point, there will be a number of files named POMAC-01.* in the directory you launched the airodump-ng window. In the first window (the airodump-ng window), we will use aircrack-ng to reveal the key.

Command: aircrack-ng -b CC:35:40:B8:AC:7F POMAC-01.cap

Output of the aircrack-ng process... less than 4 seconds to reveal:


Conclusion


STOP USING WEP!!!! Also, don't name your AP something that reveals possible attack avenues. The SSIDs of the WPA/WPA2 AP with names hobby/interest related just help an attacker figure out what dictionary to base their attack. (i.e. the Golf based SSIDs have a golf themed password, Music/Band based SSIDs... etc).

Also, turn off the SSID broadcast.

Wednesday, February 11, 2015

Linux OpenLDAP 2.4 Install using TLS to Federate Fedora 20 - 21 / Redhat 6+


LDAPwormRecently, I have been setting up a lot of Linux boxes on a closed internal network. For scaling and maintainability, I decided to setup OpenLDAP to federate all of the Linux boxes together. This was pretty straight-forward after I sifted through all of the documentation. There are many resources on the web that will give you step-by-step pointers on how to set it up. Unfortunately, they have many issues with them.

Some issues would include:
  • LDAP TLS connectivity is required in newer version of Linux (Redhat 6+, Fedora 20 / 21, etc.)
    • Creation of the TLS certificates based on the site you go to is either dead wrong, slightly wrong, or marginally accurate.
    • None of the links I found accurately described how to test if your TLS configuration is working.
  • Some authors suggest editing the /etc/sysconfig/authconfig file and setting FORCELEGACY=yes (Fixes the TLS mandatory requirement). This is a bad idea.... if you really want to do this do it in sssd.conf don't pollute the whole OS.  Edit /etc/sssd/sssd.conf in the [domain/default] section: ldap_tls_reqcert = never.
  • Some authors suggest turning off SELinux to get LDAP to work...huh? BAD IDEA!
  • Some authors suggest editing the /etc/openldap/slapd.d files (i.e. cn=config files) directly. This is not correct. You need to use ldapmodify to edit these. Otherwise you corrupt the CRC on the files, which is an integrity check for unauthorized modification. Sure they will load... with a warning.... but its not right. The first line clearly states:   
    • # AUTO-GENERATED FILE - DO NOT EDIT!! Use ldapmodify.
  • Multiple methods of integrating LDAP which don't mix and match. (pam_ldap, nss-pam-ldapd, nss_ldap, sssd_ldap...etc)
  • Various other things.....    

Basically, what you get on the internet is  roughly worth what you paid for it..... :-(

Now, that said... nobody is paying me either. So, what I am going to detail is a very basic configuration of LDAP (for now... I'll add more later...I hope).

This configuration will be:
  • Encrypted using self-signed certs
  • Allow users to login on any LDAP configured client/server

WARNING: This configuration will not be fully functional (it will allow you to login on multiple nodes, control SUDO, and control password policy, but:
  • It will NOT cover setting up the newer (OLC, cn=config) model of the LDAP config. We will use the standard slapd.conf file for ease of explanation. It is important to migrate to the (OLC, cn=config) since it was introduced in OpenLDAP 2.3 and will be a forced upgrade soon. (Later, I'll update how to use this)
  • Password policy is additionally controlled via PAM using the setting for pam_cracklib and pam_unix in your /etc/pam.d/system-auth (or system-auth-ac) file. Something like this on all nodes in your architecture:

             password    required      pam_cracklib.so retry=3 minlen=14 dcredit=-2 ucredit=-2 ocredit=-2 lcredit=-2 difok=4 maxclassrepeat=3
             password    sufficient    pam_unix.so min=14 remember=24 sha512 shadow nullok try_first_pass use_authtok
             password    sufficient    pam_sss.so use_authtok
             password    required      pam_deny.so


This tutorial will use the built-in System Security Services Daemon(sssd) and the Pluggable Authentication Module (PAM) that come with Fedora 20 and Redhat 6.5 (any Linux really natively). Redhat and Fedora have a few differences, but I'll detail them in the install process.

Note: All steps below are conducted as root.

SERVER SETUP

Step 1) Install the required modules using YUM

  • OpenSSL used for certificate testing and creation
  • gnutls-utils used for certificate testing
  • openldap-servers libraries for the LDAP Server
  • openldap-clients libraries used on both the server and clients

[root@demo juser]# yum install openssl gnutls-utils openldap-servers openldap-clients

=================================================================================================
 Package                    Arch             Version                     Repository         Size
=================================================================================================
Installing:
 gnutls-utils               x86_64           3.1.28-1.fc20               updates           191 k
 openldap-clients           x86_64           2.4.39-4.fc20               updates           186 k
 openldap-servers           x86_64           2.4.39-4.fc20               updates           2.1 M
Updating:
 openssl                    x86_64           1:1.0.1e-41.fc20            updates           707 k
Installing for dependencies:
 autogen-libopts            x86_64           5.18-1.fc20                 fedora             65 k
 gnutls-dane                x86_64           3.1.28-1.fc20               updates            52 k
Updating for dependencies:
 openssl-libs               x86_64           1:1.0.1e-41.fc20            updates           919 k

Transaction Summary
=================================================================================================
Install  3 Packages (+2 Dependent packages)
Upgrade  1 Package  (+1 Dependent package)

NOTE: If you want SUDO to work/be controlled via LDAP.
1) You need to install sssd-common. (yum install sssd-common)
2)  copy /usr/share/doc/sudo-1.8.6p3/schema.OpenLDAP to /etc/openldap/schema/schema.OpenLDAP. (OpenLDAP Server only)
3) Edit /etc/sssd/sssd.conf and add:
           #### In the [domain/default] section #####
           sudo_provider=ldap
           ldap_sudo_search_base=ou=SUDOers,dc=pomacintegrations,dc=com
           ldap_sudo_full_refresh_interval=86400
           ldap_sudo_smart_refresh_interval=3600
           #### In the [sssd] section #####
           services = nss, pam, sudo
4) Edit /etc/nsswitch/conf and add:
           sudoers:    files sss
 5) In /etc/openldap/ldap.conf add
           sudoers_base  ou=SUDOers,dc=pomacintegrations,dc=com

Step 2) Generate a default password to use with slappasswd. You can use my encrypted pattern, if you want. If you choose to do it with the same word, the encrypted text will differ due to salting of the password, it is output as salted SHA.


[root@demo juser]# slappasswd
New password: HelloWorld
Re-enter new password: HelloWorld
{SSHA}U1PvxYKpmMLQ7IeGgFhr0vahphVmbho8

Step 3) Configure /etc/openldap/ldap.conf

[root@demo juser]# nano /etc/openldap/ldap.conf

Here is a copy of my file:
#
# LDAP Defaults
#

# See ldap.conf(5) for details
# This file should be world readable but not world writable.

#BASE   dc=example,dc=com
#URI    ldap://ldap.example.com ldap://ldap-master.example.com:666

#SIZELIMIT      12
#TIMELIMIT      15
#DEREF          never

ssl             start_tls
TLS_CACERTDIR   /etc/openldap/certs
TLS_REQCERT     allow
BASE            dc=example,dc=com
#               for the next two items
#                mine is 192.168.1.18
URI             ldaps://192.168.1.18
HOST            192.168.1.18
# Turning this off breaks GSSAPI used with krb5 when rdns = false
SASL_NOCANON    on
          # If your were adding sudo via LDAP... otherwise leave this line out
          sudoers_base  ou=SUDOers,dc=pomacintegrations,dc=com

          pam_filter    objectClass=posixAccount
          pam_lookup_policy yes

Step 4) Configure /etc/openldap/slaps.conf

NOTE: The below file will work on both Redhat and Fedora. Redhat comes with a sample file in you can copy over with:

[root@demo juser]# cp /usr/share/openldap-servers/slapd.conf.obsolete /etc/openldap/slapd.conf
(COMMAND WILL NOT WORK ON FEDORA)

Fedora comes with a slapd.ldif file, as they expect you to use the (OLC, cn=config) model to setup the instance. I'm not covering right now ... so use the below file. 

[root@demo juser]# nano /etc/openldap/slapd.conf

I have highlighted in red below the lines that need to change or may need to change. The key paths and filenames, if you use my commands will match. Password will change... please don't use HelloWorld!. Your domain will change... unless you are setting up "pomacintegrations.com"....




Here is a copy of the slapd.conf file:

#
# See slapd.conf(5) for details on configuration options.
# This file should NOT be world readable.
#
include         /etc/openldap/schema/corba.schema
include         /etc/openldap/schema/core.schema
include         /etc/openldap/schema/cosine.schema
include         /etc/openldap/schema/duaconf.schema
include         /etc/openldap/schema/dyngroup.schema
include         /etc/openldap/schema/inetorgperson.schema
include         /etc/openldap/schema/java.schema
include         /etc/openldap/schema/misc.schema
include         /etc/openldap/schema/nis.schema
include         /etc/openldap/schema/openldap.schema
include         /etc/openldap/schema/ppolicy.schema
include         /etc/openldap/schema/collective.schema
          # For SUDO Policy to work
include         /etc/openldap/schema/schema.OpenLDAP


# Allow LDAPv2 client connections.  This is NOT the default.
allow bind_v2

# Do not enable referrals until AFTER you have a working directory
# service AND an understanding of referrals.
#referral       ldap://root.openldap.org

pidfile         /var/run/openldap/slapd.pid
argsfile        /var/run/openldap/slapd.args

# Load dynamic backend modules
# - modulepath is architecture dependent value (32/64-bit system)
# - back_sql.la overlay requires openldap-server-sql package
# - dyngroup.la and dynlist.la cannot be used at the same time

# modulepath /usr/lib/openldap
# modulepath /usr/lib64/openldap

# moduleload accesslog.la
# moduleload auditlog.la
# moduleload back_sql.la
# moduleload chain.la
# moduleload collect.la
# moduleload constraint.la
# moduleload dds.la
# moduleload deref.la
# moduleload dyngroup.la
# moduleload dynlist.la
# moduleload memberof.la
# moduleload pbind.la
# moduleload pcache.la
moduleload ppolicy.la
# moduleload refint.la
# moduleload retcode.la
# moduleload rwm.la
# moduleload seqmod.la
# moduleload smbk5pwd.la
# moduleload sssvlv.la
# moduleload syncprov.la
# moduleload translucent.la
# moduleload unique.la
# moduleload valsort.la

# The next three lines allow use of TLS for encrypting connections using a
# dummy test certificate which you can generate by running
# /usr/libexec/openldap/generate-server-cert.sh. Your client software may balk
# at self-signed certificates, however.
TLSCACertificateFile   /etc/openldap/cacerts/ca-bundle.crt
TLSCertificateFile      /etc/openldap/certs/slapd.pem
TLSCertificateKeyFile   /etc/openldap/certs/slapd.pem

TLSCipherSuite HIGH:MEDIUM:-SSLv2

#######################################################################
# database definitions
#######################################################################

database        bdb
suffix          "dc=pomacintegrations,dc=com"
checkpoint      1024 15
rootdn          "cn=Manager,dc=pomacintegrations,dc=com"
# HelloWorld from Step 2.
rootpw          {SSHA}U1PvxYKpmMLQ7IeGgFhr0vahphVmbho8

loglevel        256
sizelimit       unlimited
# Cleartext passwords, especially for the rootdn, should
# be avoided.  See slappasswd(8) and slapd.conf(5) for details.
# Use of strong authentication encouraged.
# rootpw                secret
# rootpw                {crypt}ijFYNcSNctBYg

          overlay ppolicy
          ppolicy_default "cn=default,ou=policies,dc=pomacintegrations,dc=com"


# The database directory MUST exist prior to running slapd AND
# should only be accessible by the slapd and slap tools.
# Mode 700 recommended.
directory       /var/lib/ldap

# Indices to maintain for this database
index objectClass                       eq,pres
index ou,cn,mail,surname,givenname      eq,pres,sub
index uidNumber,gidNumber,loginShell    eq,pres
index uid,memberUid                     eq,pres,sub
index nisMapName,nisMapEntry            eq,pres,sub

# Replicas of this database
#replogfile /var/lib/ldap/openldap-master-replog
#replica host=ldap-1.example.com:389 starttls=critical
#     bindmethod=sasl saslmech=GSSAPI
#     authcId=host/ldap-master.example.com@EXAMPLE.COM
# Sample security restrictions
#       Require integrity protection (prevent hijacking)
#       Require 112-bit (3DES or better) encryption for updates
#       Require 63-bit encryption for simple bind
# security ssf=1 update_ssf=112 simple_bind=64

##############################################
##### START ACL RULES FOR DATABASE    ########
##############################################



access to attrs="userPassword"
        by anonymous auth
        by self write
        by set="[cn=ldapOSAdmin,ou=Groups,
dc=pomacintegrations,dc=com]/memberUid & user/uid" write
        by * none

access to attrs="pwdReset"
        by set="[cn=ldapOSAdmin,ou=Groups,
dc=pomacintegrations,dc=com]/memberUid & user/uid" write
        by * read

access to attrs=uid,cn,objectClass,loginShell,homeDirectory,uidNumber,gidNumber
        by * read

access to *
        by self write
        by * read


##############################################
###### END ACL RULES FOR DATABASE    #########
##############################################

Step 5) FEDORA: Configure /etc/sysconfig/slapd or REDHAT Configure /etc/sysconfig/ldap

Here is a copy of the /etc/sysconfig/slapd file: (/etc/sysconfig/lapd on Redhat)

[root@demo juser]# nano /etc/sysconfig/slapd
# OpenLDAP server configuration
# see 'man slapd' for additional information

# Where the server will run (-h option)
# - ldapi:/// is required for on-the-fly configuration using client tools
#   (use SASL with EXTERNAL mechanism for authentication)
# - default: ldapi:/// ldap:///
# - example: ldapi:/// ldap://127.0.0.1/ ldap://10.0.0.1:1389/ ldaps:///
SLAPD_URLS="ldapi:/// ldap:/// ldaps:///"

# DEPRICATED COMMANDS, SLAPD_URLS is current
#SLAPD_LDAP="yes"
#SLAPD_LDAPI="yes"
#SLAPD_LDAPS="yes"

# Any custom options
#SLAPD_OPTIONS=""

# Keytab location for GSSAPI Kerberos authentication
#KRB5_KTNAME="FILE:/etc/openldap/ldap.keytab"

Step 6) Initialize an empty LDAP Berkeley DB and clean up slapd.d

[root@demo juser]# rm -rf /var/lib/ldap/*
[root@demo juser]# rm -rf /etc/openldap/slapd.d/*
[root@demo juser]# cp /usr/share/openldap-servers/DB_CONFIG.example /var/lib/ldap/DB_CONFIG
[root@demo juser]# echo "" | slapadd -f /etc/openldap/slapd.conf
(This is a cheat... I should be using slapadd, but since I'm not covering (OLC, cn=config) mode...)
[root@demo juser]# slaptest -f /etc/openldap/slapd.conf -F /etc/openldap/slapd.d
[root@demo juser]# chown -Rf ldap. /etc/openldap/slapd.d/
[root@demo juser]# chown -Rf ldap. /var/lib/ldap/
[root@demo juser]# chmod 700 /var/lib/ldap/
[root@demo juser]# chmod 700 /etc/openldap/slapd.d/

Step 7) Set permissions on files conf. files and mv slapd.d config

[root@demo juser]# chown ldap. /etc/openldap/slapd.conf
[root@demo juser]# chown ldap. /etc/openldap/ldap.conf
[root@demo juser]# mv /etc/openldap/slapd.d /etc/openldap/slapd.d.IGNORE_FOR_NOW

Step 8) Create the TLS Certificates

In this step, I'm going to create some "generic" TLS certificates that are self signed. The certificate will only be valid for 365 days. This is NOT the best way to do this. Ideally, you will get certs from your hosting provider or a registered Certificate Authority. This method will work, but the certs are signed with the default CA certificate that comes with all Linux distro. Thus, the key... isn't the greatest... from a trust standpoint.

I want to avoid Certificate issues in this posting... so I'm using these certs.

[root@demo juser]# cd /etc/pki/tls/certs
[root@demo certs]# make slapd.pem

umask 77 ; \
PEM1=`/bin/mktemp /tmp/openssl.XXXXXX` ; \
PEM2=`/bin/mktemp /tmp/openssl.XXXXXX` ; \
/usr/bin/openssl req -utf8 -newkey rsa:2048 -keyout $PEM1 -nodes -x509 -days 365 -out $PEM2 -set_serial 0 ; \
cat $PEM1 >  slapd.pem ; \
echo ""    >> slapd.pem ; \
cat $PEM2 >> slapd.pem ; \
rm -f $PEM1 $PEM2
Generating a 2048 bit RSA private key
.....................................................................................+++
......................................................................................................................................................+++
writing new private key to '/tmp/openssl.wdZreJ'
-----
You are about to be asked to enter information that will be incorporated
into your certificate request.
What you are about to enter is what is called a Distinguished Name or a DN.
There are quite a few fields but you can leave some blank
For some fields there will be a default value,
If you enter '.', the field will be left blank.
-----
Country Name (2 letter code) [XX]:US
State or Province Name (full name) []:YOUR_STATE_HERE
Locality Name (eg, city) [Default City]:YOUR_CITY_HERE
Organization Name (eg, company) [Default Company Ltd]:YOUR_COMPANY_HERE
Organizational Unit Name (eg, section) []:BLANK_OR_FILL_IN
Common Name (eg, your name or your server's hostname) []:
Email Address []:

Step 9) Distribute TLS Certificates on the system into the correct folders

Note: You can use Symbolic links for this. I'm not in the tutorial. I'm just moving the files and making multiple copies of the files. This is to avoid confusion by folks trying to set this up.

[root@demo certs]# mkdir /etc/openldap/cacerts
[root@demo certs]# chown ldap. slapd.pem
[root@demo certs]# mv slapd.pem /etc/openldap/certs/.
[root@demo certs]# cp /etc/pki/tls/certs/ca-bundle.crt /etc/openldap/cacerts/.
[root@demo certs]# chown ldap. /etc/openldap/cacerts/ca-bundle.crt
[root@demo certs]# cp /etc/openldap/certs/slapd.pem /etc/openldap/cacerts/.
[root@demo certs]# chown ldap. /etc/openldap/cacerts/slapd.pem

Step 10) Start the service and test the certificate connectivity


We are going to start the service:
[root@demo certs]# service slapd start
Redirecting to /bin/systemctl start  slapd.service
(will look slightly different on Redhat when we start)
           [root@demo certs]# systemctl enable slapd

Check to see if Ports 389(LDAP) and 636(LDAPS) are bound:
[root@demo certs]# netstat -ntlup | grep slapd
tcp        0      0 0.0.0.0:636             0.0.0.0:*               LISTEN      2445/slapd      
tcp        0      0 0.0.0.0:389             0.0.0.0:*               LISTEN      2445/slapd      
tcp6       0      0 :::636                  :::*                    LISTEN      2445/slapd      
tcp6       0      0 :::389                  :::*                    LISTEN      2445/slapd      

Test Certificate: (Need to CNTRL-C out of this in Redhat)
[root@demo certs]# gnutls-cli -p 636 192.168.1.18

Processed 153 CA certificate(s).
Resolving '192.168.1.18'...
Connecting to '192.168.1.18:636'...
- Certificate type: X.509
- Got a certificate list of 1 certificates.
- Certificate[0] info:
 - subject `C=US,ST=VA,L=Fairfax,O=POMAC Integrations Inc.,CN=192.168.1.18', issuer `C=US,ST=VA,L=Fairfax,O=POMAC Integrations Inc.,CN=192.168.1.18', RSA key 2048 bits, signed using RSA-SHA1, activated `2015-02-12 01:27:42 UTC', expires `2016-02-12 01:27:42 UTC', SHA-1 fingerprint `7f9d8be15a1fdeb88d9bc2f3b3f9e5f9870aa48b'
        Public Key Id:
                a6841e8e4ffb8f962a560f480527e1cdc5cd3891
        Public key's random art:
                +--[ RSA 2048]----+
                |  +o..o*         |
                | . =..E o        |
                |  ..o  .         |
                |  .  .           |
                | . .o . S        |
                |  .+oo o         |
                |  ..+o..         |
                |  oo .+.         |
                | . .++o..        |
                +-----------------+

- Status: The certificate is NOT trusted. The certificate issuer is unknown.
*** Verifying server certificate failed...
*** Fatal error: Error in the certificate.
*** Handshake has failed
GnuTLS error: Error in the certificate.

You should get a certificate output like the above. Since it is self-signed, Fedora will really complain and terminate the connection. Redhat doesn't complain, as much, and will keep the connection open. In Redhat you will need to CNTRL-C to end the connection. (Don't worry, we have configured LDAP above to accept self-signed certs).

The above should all work. I have dryrun this on multiple platforms. The important thing here is that the certificate is received and printed out. If not, check the permissions on the files in /etc/openldap/certs and /etc/openldap/cacerts. They need to be owned by the LDAP users and readable. Verify that the cert paths provided in /etc/openldap/ldap and /etc/openldap/slapd.conf are accurate. Then, restart the slapd service (service slapd restart). Then, try connecting again. (i.e. make sure you followed the above steps :-/ )

Step 11) Create an LDIF file to populate LDAP with some groups and users

[root@demo certs]# cd ~/
[root@demo certs]# nano sample_org.ldif

Contents of the sample_org.ldif file
# Create a base for Directory Information Tree (DIT)
dn: dc=pomacintegrations,dc=com
objectClass: top
objectClass: dcObject
objectclass: organization
o: Pomac Integrations Organization
dc: pomacintegrations
description: POMAC Integrations Inc.

# Creates a Users OU (Organizational Unit)
dn: ou=Users,dc=pomacintegrations,dc=com
objectClass: organizationalUnit
ou: Users

# Creates a Groups OU
dn: ou=Groups,dc=pomacintegrations,dc=com
objectClass: organizationalUnit
ou: Groups

dn: ou=Admins,dc=pomacintegrations,dc=com
objectClass: organizationalUnit
ou: Admins

# Create a user cpoma with some basic info
dn: uid=cpoma,ou=Users,dc=pomacintegrations,dc=com
uid: cpoma
cn: cpoma
sn: 1
objectClass: top
objectClass: posixAccount
objectClass: inetOrgPerson
loginShell: /bin/bash
homeDirectory: /home/cpoma
uidNumber: 20001
gidNumber: 20001
# HelloWorld Password from Earlier
userPassword: {SSHA}U1PvxYKpmMLQ7IeGgFhr0vahphVmbho8
gecos: Craig Poma (XXX-XXX-XXXX)
          dn: cn=cpoma,ou=Groups,dc=pomacintegrations,dc=com
          objectClass: posixGroup
          objectClass: top
          cn: cpoma
          gidNumber: 20001
          memberuid: uid=cpoma

          # Creates a ldapOSAdmin group under Groups OU for use
          # in the /etc/sudoers file
dn: cn=ldapOSAdmin,ou=Groups,dc=pomacintegrations,dc=com
objectClass: posixGroup
objectClass: top
cn: ldapOSAdmin
gidNumber: 20000
memberuid: uid=cpoma
          # Creates Policy Branch
          dn: ou=SUDOers,dc=pomacintegrations,dc=com
          objectClass: top
          objectClass: organizationalUnit
          ou: SUDOers

          # Creates SUDOers Default Branch
          dn: cn=default,ou=SUDOers,dc=pomacintegrations,dc=com
          objectClass: top
          objectClass: sudoRole
          cn: default
          description: SUDO Rules Container
          sudoOption: env_keep+=SSH_AUTH_SOCK

          # Creates Policy For User cpoma
          dn: cn=sudo_cpoma,ou=SUDOers,dc=pomacintegrations,dc=com
          objectClass: top
          objectClass: sudoRole
          cn: sudo_cpoma
          sudoUser: cpoma
          sudoHost: ALL
          sudoCommand: ALL

          #Creates Policy Branch for Passwords
          dn: ou=policies,dc=pomacintegrations,dc=com
          objectClass: top
          objectClass: organizationalUnit
          ou: policies

          #Insert Default Policy
          # 7 Days = 604800
          # 15 minutes = 900
          # 180 Days = 1555200
          # 2 days = 172800
          dn: cn=default,ou=policies,dc=pomacintegrations,dc=com
          cn: default
          objectClass: pwdPolicy
          objectClass: device
          objectClass: top
          pwdMinLength: 14
          pwdSafeModify: FALSE
          pwdInHistory: 24
          pwdAllowUserChange: TRUE
          pwdAttribute: userPassword
          pwdExpireWarning: 604800
          pwdGraceAuthNLimit: 5
          pwdLockout: TRUE
          pwdLockoutDuration: 900
          pwdMaxFailure: 5
          pwdMaxAge: 15552000
          pwdMinAge: 172800
          pwdMustChange: TRUE
          pwdCheckQuality: 1


Step 12) Populate the LDAP Database

[root@demo ~]# ldapadd -x -D "cn=Manager,dc=pomacintegrations,dc=com" -W -f sample_org.ldif
Enter LDAP Password: HelloWorld
adding new entry "dc=pomacintegrations,dc=com"

adding new entry "ou=Users,dc=pomacintegrations,dc=com"

adding new entry "ou=Groups,dc=pomacintegrations,dc=com"

adding new entry "ou=Admins,dc=pomacintegrations,dc=com"

adding new entry "uid=cpoma,ou=Users,dc=pomacintegrations,dc=com"

adding new entry "cn=cpoma,ou=Groups,dc=pomacintegrations,dc=com"

adding new entry "cn=ldapOSAdmin,ou=Groups,dc=pomacintegrations,dc=com"

Step 13) Perform Client Configuration on LDAP Server

The easiest way to do this is to use the authconfig-tui utility. It will not set all of the options to optimally configure LDAP and SSSD support. It will configure it to "work". Later, I'll come back and describe the extra changes needed to better configure LDAP.

[root@demo ~]# authconfig-tui
 See graphics.


Capture1

Fill in your accurate IP and Base DN info

Capture2


Edit /etc/sssd/sssd.conf, Add the following the the [domain/defaults] section

          ldap_tls_cacert = /etc/openldap/cacerts/ca-bundle.crt

Register the SSSD service options
[root@demo ~]# authconfig \
--enablesssd \
--enablesssdauth \
--enablelocauthorize \
--enableldap \
--enableldapauth \
--ldapserver=ldaps://192.168.1.18:636 \
--enableldaptls \
--ldapbasedn=dc=pomacintegrations,dc=com \
--enablerfc2307bis \
--enablemkhomedir \
--enablecachecreds \
--update 


[root@demo ~]# service sssd restart
 

Step 14) Test

[root@demo ~]# ldapsearch -x -b "dc=pomacintegrations,dc=com"

(Database contents will be listed)


[root@demo ~]# getent passwd cpoma
cpoma:*:20001:20001:Craig Poma (XXX-XXX-XXXX):/home/cpoma:/bin/bash
[root@demo ~]# id cpoma
uid=20001(cpoma) gid=20001(cpoma) groups=20001(cpoma)
[root@demo ~]# ssh cpoma@localhost
Fedora release 20 (Heisenbug)
cpoma@localhost's password: HelloWorld
Creating home directory for cpoma.
[cpoma@demo ~]$

Server Summary

As you can see, we can now login using LDAP on the Server. Next we need to configure the clients. They are pretty easy to configure. You just need to distribute the keys to them (owned by root in this case), update the /etc/openldap/ldap.conf file, and run the authconfig-tui utility.

LDAP Client Configuration

Coming Soon... (it's in the above...kind of)
  • yum install openssl gnutls-utils openldap-clients sssd-common
  • Perform Step 3 (See note in Step 1 if you want SUDO to work via LDAP on Clients)
  • Copy Certs to the correct directories on the client from Step 9 . They should be owned by root
  • Perform Step 13
  • Done.... I'll expand later... it is late...

Friday, January 30, 2015

DM-CRYPT (LUKS) Setup on New Volume / Mount Point or EBS Volume


I have recently had to do some work complying with "encryption at rest" of various data. There are many ways to handle this, but the target environment in my case was completely cloud-based and doesn't really allow for user-interaction during the boot process (to enter a password to decrypt the drive before boot time). Many solutions like TrueCrypt, Checkpoint, even full disk encryption using LUKS will require a password entry before boot, since the boot volume is encrypted. To avoid this issue during boot, but meet the requirement, I chose to use native LUKS (Linux Unified Key Setup) and only encrypt one volume/mount point.

I'm doing the setup for this tutorial on a Fedora 21 VM hosted on Oracle VirtualBox. I chose to add an empty new virtual hard drive off of my VM in VirtualBox. In Amazon AWS, you would add a new EBS volume to your EC2 instance. This setup will be the same on most Linux distros in either environment.

NOTE: All of this is performed as root.

Step #1: Make sure the required cryptsetup libraries are on your machine. If not install them.

[root@localhost juser]# cryptsetup --version
cryptsetup 1.6.6
In this case, it is present. This library is standard on most newer Linux distros. If you need to install it. You can install it with yum or apt-get.

[root@localhost juser]# yum install cryptsetup
 or (depending on Linux distro)
[root@localhost juser]# apt-get update
[root@localhost juser]# apt-get install cryptsetup
Step #2: Figure out where the mount point is (i.e. what device is is?)

  To determine this, we are going to run a few fdisk commands to determine the device and if it is empty and matches my known drive size. For this example, I'm using a 1GB drive. It will show up as /dev/sdb. In an Amazon AMI, this mount point will be /dev/xvdb.

[root@localhost juser]# fdisk -l

Disk /dev/sda: 40 GiB, 42949672960 bytes, 83886080 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: dos
Disk identifier: 0x5e44e428

Device     Boot   Start      End  Sectors  Size Id Type
/dev/sda1  *       2048  1026047  1024000  500M 83 Linux
/dev/sda2       1026048 83886079 82860032 39.5G 8e Linux LVM

Disk /dev/sdb: 1 GiB, 1073741824 bytes, 2097152 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk /dev/mapper/fedora--server-swap: 3.9 GiB, 4160749568 bytes, 8126464 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk /dev/mapper/fedora--server-root: 35.6 GiB, 38214303744 bytes, 74637312 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes


[root@localhost juser]# ls -lart /dev/sd*
brw-rw----. 1 root disk 8,  0 Jan 30 17:08 /dev/sda
brw-rw----. 1 root disk 8,  2 Jan 30 17:08 /dev/sda2
brw-rw----. 1 root disk 8,  1 Jan 30 17:08 /dev/sda1
brw-rw----. 1 root disk 8, 16 Jan 30 17:12 /dev/sdb
[root@localhost juser]#
[root@localhost juser]# fdisk -l /dev/sdb

Disk /dev/sdb: 1 GiB, 1073741824 bytes, 2097152 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
[root@localhost juser]#
[root@localhost juser]# echo -e "p\nq\n" | fdisk /dev/sdb

Welcome to fdisk (util-linux 2.25.2).
Changes will remain in memory only, until you decide to write them.
Be careful before using the write command.

Device does not contain a recognized partition table.
Created a new DOS disklabel with disk identifier 0xb558ecd7.

Command (m for help): Disk /dev/sdb: 1 GiB, 1073741824 bytes, 2097152 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: dos
Disk identifier: 0xb558ecd7

Command (m for help):
[root@ocalhost juser]#
Step #3: Partition the volume using fdisk

  I'm going to partition the volume and use the whole 1GB that I have available. You could make multiple volumes within the mount point, but I'm not going to cover that here. After it is partitioned, I check it and see that it is /var/sdb1.  In an Amazon AMI, this mount point will be /dev/xvdb1.

[root@localhost juser]# echo -e "n\np\n1\n\n\nw\n" | fdisk /dev/sdb

Welcome to fdisk (util-linux 2.25.2).
Changes will remain in memory only, until you decide to write them.
Be careful before using the write command.

Device does not contain a recognized partition table.
Created a new DOS disklabel with disk identifier 0x60e686b4.

Command (m for help): Partition type
   p   primary (0 primary, 0 extended, 4 free)
   e   extended (container for logical partitions)
Select (default p): Partition number (1-4, default 1): First sector (2048-2097151, default 2048): Last sector, +sectors or +size{K,M,G,T,P} (2048-2097151, default 2097151):
Created a new partition 1 of type 'Linux' and of size 1023 MiB.

Command (m for help): The partition table has been altered.
Calling ioctl() to re-read partition table.
Syncing disks.

[root@localhost juser]# fdisk -l /dev/sdb

Disk /dev/sdb: 1 GiB, 1073741824 bytes, 2097152 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: dos
Disk identifier: 0x60e686b4

Device     Boot Start     End Sectors  Size Id Type
/dev/sdb1        2048 2097151 2095104 1023M 83 Linux

[root@localhost juser]#

Step #4: Fill it with random data (optional, but a best practice)

 [root@localhost juser]# dd if=/dev/urandom of=/dev/sdb1
dd: writing to ‘/dev/sdb1’: No space left on device
2095105+0 records in
2095104+0 records out
1072693248 bytes (1.1 GB) copied, 102.281 s, 10.5 MB/s
[root@localhost juser]#
 
Step #5: Format it with luksFormat

[root@localhost juser]# cryptsetup luksFormat /dev/sdb1

WARNING!
========
This will overwrite data on /dev/sdb1 irrevocably.

Are you sure? (Type uppercase yes): YES
Enter passphrase: 
(PasswordYouChooseTypedHere)
Verify passphrase: (PasswordYouChooseTypedHere)
[root@localhost juser]#


Step #6: Mount it with luksOpen to /dev/mapper

[root@localhost juser]# cryptsetup luksOpen /dev/sdb1 encrypted_drive
Enter passphrase for /dev/sdb1:
[root@localhost juser]# ls -lart /dev/mapper
total 0
crw-------.  1 root root 10, 236 Jan 30 17:08 control
lrwxrwxrwx.  1 root root       7 Jan 30 17:08 fedora--server-swap -> ../dm-0
lrwxrwxrwx.  1 root root       7 Jan 30 17:08 fedora--server-root -> ../dm-1
drwxr-xr-x. 20 root root    3260 Jan 30 17:58 ..
lrwxrwxrwx.  1 root root       7 Jan 30 17:58 encrypted_drive -> ../dm-2
drwxr-xr-x.  2 root root     120 Jan 30 17:58 .
[root@localhost juser]#
Step#7: Create an EXT4 filesystem on the encrypted drive

[root@localhost juser]# mkfs.ext4 /dev/mapper/encrypted_drive
mke2fs 1.42.11 (09-Jul-2014)
Creating filesystem with 261376 4k blocks and 65408 inodes
Filesystem UUID: dbd52a8d-2a7e-4bfc-83ff-cbade6e715d4
Superblock backups stored on blocks:
        32768, 98304, 163840, 229376

Allocating group tables: done                          
Writing inode tables: done                          
Creating journal (4096 blocks): done
Writing superblocks and filesystem accounting information: done

[root@localhost juser]#

Step #8: Add it to /etc/fstab and mount it for use

[root@localhost juser]# mkdir /encrypted_drive
[root@localhost juser]# chmod 777 /encrypted_drive
(Should really be 755, but I'm just making it world writable for this example)
 
[root@localhost juser]# echo -e "/dev/mapper/encrypted_drive /encrypted_drive ext4 defaults 0 0" >> /etc/fstab
[root@localhost juser]# mount -a
[root@localhost juser]# df -h
Filesystem                       Size  Used Avail Use% Mounted on
/dev/mapper/fedora--server-root   35G  5.8G   28G  18% /
devtmpfs                         2.0G     0  2.0G   0% /dev
tmpfs                            2.0G  100K  2.0G   1% /dev/shm
tmpfs                            2.0G  752K  2.0G   1% /run
tmpfs                            2.0G     0  2.0G   0% /sys/fs/cgroup
tmpfs                            2.0G   60K  2.0G   1% /tmp
/dev/sda1                        477M  116M  332M  26% /boot
tmpfs                            396M   12K  396M   1% /run/user/1000
tmpfs                            396M     0  396M   0% /run/user/0
/dev/mapper/encrypted_drive      989M  1.3M  921M   1% /encrypted_drive
[root@localhost juser]#

 At this point, the drive is usable and will be encrypted. However, it will not remount at boot and you will have to manually cryptsetup luksOpen then mount -a at it every boot. This is disadvantageous. So, next we are going to create a keyfile and associate it with the drive. This will allow it to auto mount at boot.

Step #9: Add keyfile and add /etc/crypttab entry
[root@localhost juser]# echo -e "(Password from Step 5)" >> /root/encrypted_drive.key
[root@localhost juser]# echo -e "encrypted_drive  /dev/sdb1  /root/encrypted_drive.key  luks" >> /etc/crypttab
[root@localhost juser]# cryptsetup luksAddKey /dev/sdb1 /root/encrypted_drive.key
Enter any passphrase: (Password from Step 5)
[root@localhost juser]#

Step #10: Reboot your server and the drive should auto mount.

 After rebooting, open a console and see if the drive is present.....
[juser@localhost ~]$ df -h
Filesystem                       Size  Used Avail Use% Mounted on
/dev/mapper/fedora--server-root   35G  5.8G   28G  18% /
devtmpfs                         2.0G     0  2.0G   0% /dev
tmpfs                            2.0G  100K  2.0G   1% /dev/shm
tmpfs                            2.0G  732K  2.0G   1% /run
tmpfs                            2.0G     0  2.0G   0% /sys/fs/cgroup
tmpfs                            2.0G   64K  2.0G   1% /tmp
/dev/sda1                        477M  116M  332M  26% /boot
/dev/mapper/encrypted_drive      989M  1.3M  921M   1% /encrypted_drive
tmpfs                            396M  8.0K  396M   1% /run/user/1000
[juser@localhost ~]$
Hope this posting helps folks trying to setup an encrypted volume that auto mounts at boot time.

Tuesday, May 13, 2014

Bots and Script Kiddies - /wordpress/wp-login.php


So, on a whim, I went to clean up my sites log files. I have not done any clean up in a few years..... much less site postings or updates.... I'm too busy with my kids after work to do much research and posting after work these days.

Before purging them, I went and looked at my page stats for 2014. I was surprised to see the large volume of hit against the Wordpress login page. (I never renamed it or installed any Wordpress CAPTCHA tools to mitigate attack). I don't normally update my Wordpress site, it's more of a placeholder and traffic vehicle for LinkedIn and my Blog. It only has two pages, but the bots and script kiddies have found it and are vigorously running their standard dictionary attacks against it.....  1000's of hits per month. I know my password is decent :-).....  and please don't take this posting as a challenge. The password is decent... however... Wordpress is an older version. Folks would have better luck via that attack vector.... maybe I should go ahead an update to a newer version....

Sunday, September 15, 2013

I have a new habit!



So… guess I have a new habit… “Working Out”. I have been exercising every day for the last three weeks. At this point, I guess it’s considered a habit. Not a bad habit to have… I find that I’m calmer now that I have something to tire me out completely every day after work (not that the kids don’t also have something to do with that).
Over the last three weeks, I’ve been racking up “vitality points” like crazy. We get a discount at work for being healthy, so I have some monetary incentive to participate.  I’ve also gotten my blood work done over the last three weeks. All my vitals are healthy (cholesterol, glucose, blood pressure,  BMI, etc.).
Anyway, next week is my 1st official 5k since 2007. I’ve worked out since 2007…. just have not documented it to this level. I’ll post my results next week. :-)