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Explore the implementation of secure network connections using PKI for authentication, including hardware token storage, document signatures, secure mail, and wireless network authentication.
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PKI Network AuthenticationDartmouth Applications Robert Brentrup Educause/Dartmouth PKI Summit July 27 , 2005
Next Phase Applications • Hardware Key Storage (USB Tokens) • Application and OS Sign-on with Tokens • Document Signatures • Acrobat, Office, XML (NIH) • Secure Mail and List Server • Wireless Network Authentication • Grids
Network Auth Technologies • Wireless and Wired • 802.1x/EAP • TLS and TTLS • or LEAP, PEAP, MS-CHAP etc. • WEP, WPA - 802.1x • VPN • IPSEC standard, using Cisco proprietary • Cisco password authentication is vulnerable, • use client certificates to be secure
VPN Objectives • Secure network connections for distant office and travellers • some from home use too, local IP address • Secure some legacy applications with closed subnets • server firewall rejects connections not from Private subnet addresses • Use PKI “High Assurance” certificate (token if possible) to authenticate • Assign IP address from protected space after Radius Authentication/Authorization
VPN Implementation • Cisco 3000 VPN concentrators • (3000 can only look at OU in DN, so added OU=PrivateGroupVPN to certs) • ACL check implemented by Radius server • Members of ACL maintained with “AuthAdmin” application • Configure protected subnets on concentrator • Two redundant Radius servers for reliability • running FreeRadius 0.9.2
AuthAdmin • Each private VPN subnet intended for members of a specific group • Existing examples • Human Resources • Dean of Students Office • International Students Office • Student Health Services • Individual in the group authorized to maintain group membership, add and delete • Group membership stored in LDAP directory • Web interface for group admin
AuthAdmin UI • (screen shot)
Network Authentication Objectives • Implement additional protection for campus network services • Limit outside use of network • Protect campus users from malicious behavior of others • Eliminate possible eavesdropping
Network Authentication Implementation • Deploy 802.1x/EAP-TLS on APs and switches • Traffic is encrypted between user and AP/switch • Clients are authenticated with PKI certificates • in our case locally issued • No Passwords are exchanged (no credentials to steal)
EAP-TLS Implementation • Configure Radius • AP clients, users, EAP-TLS module • Certificate for Radius server • Provide Root certificates of trusted CAs to EAP-TLS module • Dartmouth self-signed certificates automatically accepted • Tested APs from Cisco and Aruba
Client Software • Supplicants built into Win 2000 SP4, XP SP1-2, MacOS 10.3+ • other supplicants available for these platforms • Supplicants available for Linux, Win98 and MacOS 9 (some from vendors)
Issues • Windows: • no password on Keys • no luck with tokens yet • set advanced options for server certificate validation • Certificates with UID in DN fail • Win XP SP1 had some issues with SSID and cert selection, improved in SP2 • Mac KeyChain: early versions confused by more than one key with same "name"
Greenpass Objectives • System developed to support Guest Authorization in an 802.1x EAP-TLS environment • Also useful for insiders that forgot their token • User only needs 802.1x capable machine and web browser, no additional software • Guest Introduces Public Key to Greenpass Authorization System • Host signs authorization for Guest Access using SPKI certificate delegation features • Guest then has access to controlled internal network until time limit expires
Greenpass Implementation • Use Router, AP and switch capable of VLANs to create limited use network • Recently implemented automatic VLAN switching by Radius • Modifications to FreeRadius needed • Greenpass servers run on Linux • Delegation tool is written in Java • Available as Open Source • www.dartmouth.edu/~pkilab/greenpass