One more observation on threat modeling. Discovering the database is a service:
4) Support discovery of all authorized databases services for a geographic region. Associated threat event would be: - Modification of paws protocol messages in transit to prevent discovery of authorized databases When there are multiple authorized database services we need to make sure that all authorized services are available to end devices. This implies a trust hierarchy with the regulatory authority (Gov based) as a root for a region. New regions are not going to be easy to add ... which is good since any new region also requires some level of regional conformance. Paul >-----Original Message----- >From: Stephen Farrell [mailto:[email protected]] >Sent: Monday, January 30, 2012 3:35 PM >To: Paul Lambert >Cc: [email protected]; [email protected] >Subject: Re: [paws] Threats, Services and Predicatable Availability > > >Sorry to keep on on the same thing, but it doesn't seem >to be resonating much;-) > >The charter says: "Robust privacy and security mechanisms >are needed..." > >I'm guessing its possible an analysis starting from your >suggestions below should produce a good result wrt security >but maybe less so for privacy (which is less well >understood by us all). > >How about adding "Prevent unnecessary exposure of >personally identifying information (PII)" ? > >Note that the above could me met via encryption of >PII, (with possibly high-cost key management) or by >just not sending PII when you don't need to which is >fairly cheap if you're not forced by regulation to >send it. (Since some devices presumably are not >personally identifying but others are, then maybe >there's a simple enough answer in the end...) > >S > >On 01/30/2012 10:29 PM, Paul Lambert wrote: >> >> Hi Raj, >> >>> Do you have any proposals or text w.r.t the threat model writeup? >Also >>>from an IETF perspective regarding threat models, please see Peter's >>> email: http://www.ietf.org/mail- >archive/web/paws/current/msg00592.html >>> >>> -Raj >> >> I'll spend a little time formalizing the ideas I submitted below. >However, "threats" are part of a complete set of requirements and >looking at the current proposal, I feel we need to clarify the service >that we offer before we can say what are real threats. Specifically, >the threat: >> >>>>> device which can be used maliciously. The effect of such an >>>>> attack being successful would result in a malicious client >>>>> replaying the stolen authentication/authorization secrets to >a >>>>> white space database. >> >> This is not a threat as worded... but why? >> >> We need to define what we offer, and then things that prevent or break >these offered services are potential risks that can be mapped to >threats. As a start, I propose (which I hope is mostly in line with the >use cases) two main services with some subtopics: >> >> 1) Prevent Interference of License-exempt Use with Licensed Operation > >> - Support changes in channel, time Period and region for licensed >operation >> - Support predictable availability of licensed channels >> - Support the ability to disable specific vendor/model-types from >operation when >> they are determined to be causing interference >> 2) Enable Authorized Channel Utilization for License-exempt Operation > >> - Facilitate fixed use of channels >> - Facilitate mobile use of channels >> - Facilitate indoor use of channels >> - Support predictable availability of license-exempt channels >> - Support changing of authorized channels to prevent interference >with licensed usage >> >> So, threat event is something that has a result of preventing the >promised services. The threat event either causes unapproved >interference with licensed operation, or it prevents White Space >"license-exempt" operation. >> >> The "Support Predictable Availability" is something new I'd like to >introduce for discussion. There needs to be a expectation that once you >are using a channel that your use will not be terminated abruptly in an >unanticipated manner. Right now - we are creating mechanism to quickly >cutoff a device for any reason at all (for the use case of mobile >microphones). This is actually supposed to be a predictable event with >some type of scheduling. An license-exempt devices needs to be able to >determine how long it might operate under the regulations in a >particular channel/region. Building a system where you never know when >your communications might get cut off seems like a bad idea. >> >> >> >> Paul >> >> >>> >>> On 1/27/12 5:24 PM, "ext Paul Lambert"<[email protected]> wrote: >>> >>>> It's good to have requirements based on such an analysis. This is >an >>>> interesting start, but we may be mixing threats, vulnerabilities and >>>> mechanisms. >>>> >>>> Threats are typically tied to an actor ... human or not. I'm not >sure >>>> it's worth going hard over to something like the NIST 800-30 >>> definitions >>>> of threats, but within this framework the threats are Governments, >>>> disgruntled insiders, tsunamis etc. Being the IETF we can jump more >>>> quickly to the threat event and specifics of an attack, but should >at >>>> least expand threats to include natural events and connectivity >>> problems. >>>> Robustness or emergency modes might be interesting to consider. >>>> >>>> We also have a problem in this analysis of perspective - are we >>>> considering threats as viewed from regulatory agency or the end >device >>>> owner or both. We should consider both - but they are contradictory >>>> perspectives. Users want continuity of service. Governments (the >>>> regulators) want control of the airwaves. >>>> >>>> Most of the real threats that we have are nearly impossible to >prevent >>> at >>>> the protocol level. It's still worth examining the threats to see >>> where >>>> we stand. >>>> >>>> On the current document threats: >>>> >>>>> o It is assumed that the master device or the white space database >>>>> have NOT been compromised from a security standpoint. >>>>> >>>>> Threat 1: Obtain master device authentication/authorization secrets >>>>> The master device needs to authenticate itself with the >white >>>>> space database prior to requesting channel information. The >>>>> attacker may try to get access to the secrets of the master >>>>> device which can be used maliciously. The effect of such an >>>>> attack being successful would result in a malicious client >>>>> replaying the stolen authentication/authorization secrets to >a >>>>> white space database. >>>> This does not seem consistent with the prior statement of "not >>>> compromised". >>>> Restatement >>>> >>>> Threat: User modifies a device to masquerade as another valid >certified >>>> device. >>>> >>>> This is an interesting case where threat/vulnerability/risk play >>>> together. The FCC or other regulatory agencies want traceability of >>>> devices. If a user wants to run a rogue radio, there is no reason >to >>>> access the database (low risk - no payoff). The only reason this >would >>>> be an interesting attack might be to avoid tracking and have some >>>> anonymity. >>>> >>>>> Threat 2: Spoofed white space database >>>>> A master device discovers a white space database(s) thru >which >>>>> it can query for channel information. The master device >needs >>>>> to ensure that the white space database with which it >>>>> communicates with is an authentic entity. The white space >>>>> database needs to provide its identity to the master device >>>>> which can confirm the validity/authenticty of the database. >An >>>>> attacker may attempt to spoof a white space database and >>>>> provide responses to a master device which are malicious and >>>>> result in the master device causing interference to the >primary >>>>> user of the spectrum. >>>> >>>> I think this is two types of threat events: >>>> - malicious denial of service or intentional interference with >>> incumbents >>>> - impersonation of white space database to enable operation of a >>> device >>>> that may >>>> not otherwise be possible (blocked device, unallocated channels). >>>> This may or may not >>>> interfere with incumbent devices >>>> >>>>> Threat 3: Modifying a query request >>>> ... >>>> >>>>> Threat 4: Modifying a query response >>>> Seems like these two could be lumped together ...MiTM modifies >protocol >>>> messages to: >>>> - deny service >>>> - interfere with incumbents >>>> - provide unauthorized channel usage (most likely risk IMHO) >>>> >>>>> Threat 5: Using query response information >>>>> An attacker may be a master device which is not certified >for >>>>> use by the relevant regulatory body. The attacker may listen >to >>>>> the communication between a valid master device and white >space >>>>> database and utilize the information about available >channels >>>>> in the response message by utilizing those channels. The >result >>>>> of such an attack is unauthorized use of channels by a >master >>>>> device which is not certified to operate. >>>> As stated this is a mechanism - a clearer statement might be. >>>> >>>> Threat: Unauthorized use of channels by an uncertified device. >>>> >>>> Anyone can already go to a database and find available channels. If >a >>>> device can operate without going to the database there is nothing >that >>>> paws can do to stop it operating in available or non-available >>> channels. >>>> >>>> Just to get some discussion going -here's a couple more possible >>> threats.. >>>> >>>> Threat: Third party tracking of white space device location >>>> Likely a valuable commodity to sell for advertizing with no >>> technical >>>> design or policy for privacy >>>> Threat: Database owner termination of device service for reasons >other >>>> than incumbent protection >>>> >>>> >>>> >>>> Paul >>>> >>>> >> >> _______________________________________________ >> paws mailing list >> [email protected] >> https://www.ietf.org/mailman/listinfo/paws >> _______________________________________________ paws mailing list [email protected] https://www.ietf.org/mailman/listinfo/paws
