21st June 2007 .


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Point. Step by step instructions to connection Active Directory to the Oxford Kerberos Single sign-on (SSO) framework. What is Kerberos?. Validation convention Not authorisationClient and server commonly verify. 3. Validation versus Authorisation. ?. ?. Confirmed. Approved. 4. Why Kerberos?. Single sign-onCentralised authenticationStrong encryptionNo passwords over the wire.
Transcripts
Slide 1

Dynamic Directory and Oxford Single Sign-On Bridget Lewis – ICTST Adrian Parks – OUCS

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Aim How to connection Active Directory to the Oxford Kerberos Single sign-on (SSO) framework

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What is Kerberos? Confirmation convention Not authorisation Client and server commonly validate

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Guest List Donald Duck Fred Smith Lucy Jones The Doctor Fred A. Stair Fred A. Stair Undergrad Cornflake College Authentication versus Authorisation  Authenticated Authorized

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Why Kerberos? Single sign-on Centralized validation Strong encryption No passwords over the wire

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Kerberos in Oxford Herald WebLearn Apache/IIS webservers (by means of Webauth) eDirectory Active Directory Open Directory

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So how can it work… ? Basic, truly…

Slide 8

Like this…

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Trusted Third Party 1: A, B Client A Service B Basic Kerberos Functionality A B S B A 9

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Essential Terminology Principal — client or administration with accreditations Ticket — issued for access to an administration Key Distribution Center (KDC) — issues tickets for principals in a domain Realm — set of principals in a Kerberos database, e.g. OX.AC.UK, OUCS.OX.AC.UK TGT (ticket-giving ticket) — affirms character; used to get further tickets (Single Sign-on)

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Kerberos and Active Directory Kerberos 5 actualized in AD (with included… ) Every area is a Kerberos Realm Every space controller is a KDC Many administrations can utilize Kerberos CIFS, LDAP, HTTP Kerberos is favored over NTLM Trusts between Kerberos Realms

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Integrating Active Directory with Oxford Kerberos Realm Configure Active Directory Kerberos domain to trust Oxford Kerberos domain for confirmation OX.AC.UK KDCs 1 2 Trust 3 Active Directory 4 OUCS.OX.AC.UK KDCs Client A

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Integrating Active Directory with Oxford Kerberos Realm Authorization: AD utilizes SID, not username to figure out what a client can do Usernames must exist in AD (Identity Management) Oxford usernames must be mapped to Active Directory clients fred@OUCS.OX.AC.UK fred@OX.AC.UK

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So what does this mean by and by? The "Good"... Utilize Oxford record to confirm to AD No compelling reason to issue passwords to new understudies every year Devolve secret key issues to OUCS

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Case Study St Hugh\'s College ~ 20 Public Access PCs ~ 6 00 Students, admission of ~120 every year Passwords were issued physically every year Integrated with Oxford KDCs Account creation streamlined by means of VB script Students utilize "Envoy" watchword Administrative overhead diminished for ITSS

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Case Study Language Center User base is entire college! Possibly 40000 clients Historically, all utilized one shared record Webauth in addition to Oxford SSO arrangement Users enroll for AD account by means of Webauth ensured webpage AD account produced on the fly Log into AD through the Oxford SSO arrangement "Envoy watchword" 16

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But… there are a few admonitions The "Bad"... Access from PCs not in area Including through web, e.g. Viewpoint WebAccess Some understudies don\'t have the foggiest idea about their Oxford secret word (approx 13%) Loss of outside network to focal KDCs

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...and a few issues The "Ugly"... Fallback confirmation is NTLM KDCs don\'t speak NTLM Some applications just speak NTLM Problems coordinating other working frameworks (OS X, other?)

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Summary Works extremely well in specific situations E.g. shared filestore for understudies Reduced regulatory overhead Not proper for all situations E.g. many administrations based on Active Directory (Exchange, Sharepoint, Web access to documents and so forth.) 19

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How would we set this up? Full points of interest are on the ITSS wiki: https://wiki.oucs.ox.ac.uk/itss/KerberosADTrust

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How would we set this up? Check time is in a state of harmony (all through space and to ntp source) See supplement for points of interest! 21

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How would we set this up? 2. Request a Kerberos main from the OUCS Systems Development group ( sysdev@oucs.ox.ac.uk ) krbtgt/FULL.AD.DOMAIN.NAME krbtgt/STHUGHS.OX.AC.UK krbtgt/ZOO.OX.AC.UK

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How would we set this up? 3. Change the watchword of the new principal (utilize linux.ox.ac.uk):

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How would we set this up? 4. Check time is in a state of harmony

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How would we set this up? 5. On all space controllers, part servers and workstations, introduce the Windows Support Tools and run: ksetup/addkdc OX.AC.UK kdc0.ox.ac.uk ksetup/addkdc OX.AC.UK kdc1.ox.ac.uk ksetup/addkdc OX.AC.UK kdc2.ox.ac.uk Or utilize a registry document/Group Policy (see wiki)

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How would we set this up?

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How would we set this up? 6. Make a restricted, active, transitive trust between the Kerberos domain OX.AC.UK and the Active Directory backwoods Use the secret word set in step 3.

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How would we set this up?

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How would we set this up? 7. Check time is in a state of harmony

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How would we set this up? 8. Include a name mapping for AD record to the Kerberos domain Format is oucs1234@OX.AC.UK Note capitalized OX.AC.UK

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How would we set this up?

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How would we set this up? 9. Reboot workstation and sign in

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Demo

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Contact points of interest bridget.lewis@ict.ox.ac.uk adrian.parks@oucs.ox.ac.uk

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Some connections ITSS Wiki: https://wiki.oucs.ox.ac.uk/itss/KerberosADTrust MIT: Designing an Authentication System: A Dialog in Four Scenes http://web.mit.edu/kerberos/www/dialogue.html Microsoft: http://www.microsoft.com/technet/prodtechnol/windows2000serv/howto/kerbstep.mspx Kerberos: The Definitive Guide (Jason Garman/O\'Reilly) http://www.amazon.co.uk/Kerberos-Definitive-Guide-Jason-Garman/dp/0596004036/ref=sr_1_1/202-9173258-1666237?ie=UTF8&s=books&qid=1182273864&sr=8-1

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Appendix A — Utilities 2003 Resource Kit Utilities Kerbtray (GUI) Klist (charge line) Support Tools Utilities (from 2003 CD) Ksetup (order line) Ktpass (summon line)

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Kerbtray shows tickets Picture demonstrates TGTs for ITSSCONFADDEMO.OX.AC.UK and OX.AC.UK

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Kerbtray Picture indicates tickets for administrations in Active Directory Realm

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Klist — as Kerbtray however summon line

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Support Tools Ksetup Set up domain data E.g. set KDCs for a given domain Ktpass Manipulating principals

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MIT Kerberos for Windows http://web.mit.edu/kerberos/dist/Another method for survey tickets Maintains its own particular ticket store Can import tickets from Microsoft reserve Some applications can utilize these tickets

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Network Identity Manager

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Appendix B — Additional Notes Time must be inside 5 minutes of KDC time Logon may bomb discontinuously if logon permitted before system completely instated (XP/2003) Group Policy setting Computer Configuration/Administrative Templates/System/Logon Enable setting " Always sit tight for system on PC startup or client logon " Terminal Services Patch http://support.microsoft.com/default.aspx?scid=KB;EN-US;902336

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Short History of Time All DCs match up to PDC emulator (programmed) Member servers and workstations synchronize to Domain Controllers (programmed) PDC emulator must be sync\'d to ntp source Must upgrade on the off chance that you move PDC emulator part w32tm/config/manualpeerlist: " ntpserver1 ntpserver2 ntpserver3 "/syncfromflags:manual/reliable:yes/redesign http://technet2.microsoft.com/windowsserver/en/library/ce8890cf-ef46-4931-8e4a-2fc5b4ddb0471033.mspx?mfr=true 45

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Automated Account Creation OUCS can give daily overhaul of Oxford usernames and other data to every unit http://www.oucs.ox.ac.uk/enrollment/card_data_2006.xml.ID=body.1_div.9 Use scripts to bolster into Active Directory 46

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AS 1: A, TGS 2: A, B TGS Client A Service B Full Kerberos Functionality KDC — 2 sections AS: Authentication Server TGS: Ticket Granting Server A B C S C S KDC B A 47

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Other notes of intrigue Workstation confirms as well: issues for x-domain auth. DC devolution — KDC patches accessible Macs eDir preauth, timestamps, life expectancy of tickets and so forth 48

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Appendix C Use Wireshark to watch the Kerberos trade

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