1. UPnP Security
Vic Lortz
Chair, Security WC
Intel Corporation

2. Agenda
Introduction
Fundamentals: security mechanisms and protection for each phase of UPnP
Scenarios
Remote plugfest learnings

3. UPnP Today UPnP is about empowering ordinary people
Introduction
UPnP Today
UPnP is about empowering ordinary people
automatic networking
no need for technical expertise
convenient, “it just works”
presumes a secure network

4. The Expanding Universe
Introduction
The Expanding Universe
Wireless, apartments, dorms, hotels, enterprise networks…
Remote access
Hackers
Viruses

5. What’s Needed: Security
Introduction
What’s Needed: Security
Scenarios and requirements defined early 2001
Security Working Committee established August, 2001
Version 0.8 of spec docs completed March, 2002
Sample implementations and 3rd plugfest underway

6. Spec documents DeviceSecurity – primary service
Introduction
Spec documents
DeviceSecurity – primary service
SecurityConsole – service for publishing keys and names, distributing certificates
DeviceStealth – service for securing discovery
AuditService – service for event logs (not just security-related)
SecureDevice – device template, contains overall architectural description, secure event mechanism

7. Introduction
Current Status
Sample implementations: Intel, LGE, Siemens (2 independent), Sony
Microsoft is enhancing test tool
On track to complete DeviceSecurity and SecurityConsole services by end of 2002.
DeviceStealth, secure eventing, and AuditService to follow soon
First customer: IGD V2 (A/V also interested).

8. Benefits and Costs Benefits Costs Protects from “bad guys”
Introduction
Benefits and Costs
Benefits
Protects from “bad guys”
Enables high-value services (e.g., remote power metering, medical monitoring)
Costs
Additional code in devices, cycles to do crypto
Larger packet sizes on network
Incompatible with legacy UPnP (this is a feature)
Some configuration is required
Challenge is to minimize configuration without losing security

9. Version 2 (best guess)
V2 solution will probably be almost identical to V1 solution
Encryption strategy probably will be different
Secure eventing definitely will be different
V1 UPnP Security is already very close to WS-Security (and related specs)
V2 UPnP Security will be a proper subset of WS-Security
Microsoft is working to make sure UPnP requirements are addressed in WS-Security

10. UPnP Security Fundamentals

11. Fundamentals
Principals
Principals are “raw” public keys (no expensive Public Key Infrastructure)
Key hashes are principal identifiers
Users can assign local names to keys
Key values are passed by SOAP (for control actions) or in self-signed X.509 certificates (for presentation pages)
Groups of keys can be defined

12. Permissions XML elements defined by device manufacturer
Fundamentals
Permissions
XML elements defined by device manufacturer
Permissions are abstractions (do not map 1:1 onto UPnP actions)
Devices can also define named sets of permissions (profiles)
Can include parameters
E.g., “<read/>”, “<Administrator/>”, “<user><name> Frodo </name></user>”

13. Access Control Lists <entry> <subject> {<hash> or
Fundamentals
Access Control Lists
<entry>
<subject> {<hash> or
<any/>} </subject>
<access> {permission elements or <all/>} </access>
<valid> {optional <not-before> and/or <not-after>} </valid>
</entry>

14. Discovery: DeviceStealth
Fundamentals
Discovery: DeviceStealth
Device advertises itself as generic “SecureDevice” or “BasicDevice”
Full device description obtained via access-controlled SOAP actions
IsTypeSupported()
GetDeviceDetails()

15. Fundamentals
Control: Secure SOAP
XML Dsig-based signatures and anti-replay in SOAP header
SetSessionKey() – binds symmetric keys with public keys
DecryptAndExecute() – for privacy, encrypts and tunnels entire HTTP packet
Minimal (null) canonicalization
Crypto algorithms: RSA, SHA1-HMAC, AES

16. (XML signature, {key info}, Freshness block for anti-replay)
Fundamentals
Secure SOAP Message
HTTP Header
SOAP Envelope
SOAP Header
(XML signature, {key info},
Freshness block for anti-replay)
SOAP Body
(UPnP Action)

17. Fundamentals
Secure Eventing
Requires implementation of DeviceSecurity to establish session keys
Secure subscribe call includes 4 new headers
KEY-ID, IV, KEY-SEQ, HMAC
Events are encrypted and signed using the designated session keys

18. Fundamentals
Presentation Pages
Device (server) authentication with self-signed X.509 certificate
Browser (client) also authenticates with self-signed certificate
Permissions and ACLs also apply to presentation pages, based on the public key in the browser certificate

19. Authorization Certificates
Fundamentals
Authorization Certificates
Equivalent to signed ACL
entries
also include issuer, device public key ID, and signature
Enable small ACLs
Support constrained delegation of permissions

20. The Power of Delegation
Fundamentals
The Power of Delegation
Provides scalable access control
applicable to hierarchical organizations
Enables flexible business models
subcontractors
constrained delegation limits powers (liability)
Auditable (better than sharing passwords)

21. Scenarios

22. Fundamentals
Bootstrapping Trust
Need some way to establish trust of control point keys
Public keys can be sent in the clear, but need out-of-band mechanism to bootstrap trust
Hardware-based (e.g., IR)
Default method (SecurityConsole)

23. New Device Introduction
Scenarios
New Device Introduction
Security
Console
Device
discovery
GetPublicKeys()
TakeOwnership()

24. Control Point Introduction
Scenarios
Control Point Introduction
Control
Point
Security
Console
discovery
PresentKey()

25. Access Control Configuration
Scenarios
Access Control Configuration
Security
Console
Device
(prior TakeOwnership…)
GetDefinedPermissions()
AddACLEntry()

26. Control Point Uses Device
Scenarios
Control Point Uses Device
Control
Point
Device
GetPublicKeys()
SetSessionKeys()
SomeAction() + sig
or DecryptAndExecute()

27. Access Control Using Certs
Scenarios
Access Control Using Certs
Security
Console
Control
Point
Device
GetMyCertificates()
CacheCertificate()
optional step…
SomeAction()
+ sig + cert(s)

28. Summary UPnP Security 1.0 is nearly complete
V2 Security will be similar, especially in the areas of trust bootstrapping and authorization
Your customers will expect and demand security
Toolkits and O/S support will be available soon (stay tuned)

29. Collateral http://forum.upnp.org/archives/security.html

30. Remote Plugfest Learnings

31. Motivation
Two and three day plug-fests are not long enough to resolve complicated issues
Fixing some of these problems can be very invasive to code
Current economic climate dictates that travel to numerous plugfests is infeasible

32. Basic Solution
UPnP is a network-based protocol, so let’s use the Internet
Rather than use SSDP, explicitly load description documents using URLs communicated out-of-band
Firewall workarounds:
Put devices outside firewall
Use a VPN
Target a few actions every week between companies, testing during agreed times
Requires commitment for at least one person at each company to be available for 1 to 2 hours a week

33. Impact
Raises level of assurance that implementations will work together
Don’t come to F2F plugfests hoping things will “just work”
Makes F2F plugfests more productive
Allows implementers to work on real issues, instead of tiny mistakes
Allows for accurate communication of status for planning purposes

34. Acronyms XML Dsig – XML Digital Signature XML Enc – XML Encryption
SOAP – Simple Object Access Protocol
PKI – Public Key Infrastructure (e.g., X.509)

35. For the interconnected lifestyle