{"action":"created","issue":{"url":"https://api.github.com/repos/usnistgov/800-63-3/issues/351","repository_url":"https://api.github.com/repos/usnistgov/800-63-3","labels_url":"https://api.github.com/repos/usnistgov/800-63-3/issues/351/labels{/name}","comments_url":"https://api.github.com/repos/usnistgov/800-63-3/issues/351/comments","events_url":"https://api.github.com/repos/usnistgov/800-63-3/issues/351/events","html_url":"https://github.com/usnistgov/800-63-3/issues/351","id":176145891,"number":351,"title":"Issues with SMS Deprecation rationale","user":{"login":"cmccolgan","id":2104131,"avatar_url":"https://avatars.githubusercontent.com/u/2104131?v=3","gravatar_id":"","url":"https://api.github.com/users/cmccolgan","html_url":"https://github.com/cmccolgan","followers_url":"https://api.github.com/users/cmccolgan/followers","following_url":"https://api.github.com/users/cmccolgan/following{/other_user}","gists_url":"https://api.github.com/users/cmccolgan/gists{/gist_id}","starred_url":"https://api.github.com/users/cmccolgan/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/cmccolgan/subscriptions","organizations_url":"https://api.github.com/users/cmccolgan/orgs","repos_url":"https://api.github.com/users/cmccolgan/repos","events_url":"https://api.github.com/users/cmccolgan/events{/privacy}","received_events_url":"https://api.github.com/users/cmccolgan/received_events","type":"User","site_admin":false},"labels":[{"id":369794812,"url":"https://api.github.com/repos/usnistgov/800-63-3/labels/63B","name":"63B","color":"c5def5","default":false}],"state":"open","locked":false,"assignee":{"login":"jimfenton","id":1020212,"avatar_url":"https://avatars.githubusercontent.com/u/1020212?v=3","gravatar_id":"","url":"https://api.github.com/users/jimfenton","html_url":"https://github.com/jimfenton","followers_url":"https://api.github.com/users/jimfenton/followers","following_url":"https://api.github.com/users/jimfenton/following{/other_user}","gists_url":"https://api.github.com/users/jimfenton/gists{/gist_id}","starred_url":"https://api.github.com/users/jimfenton/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/jimfenton/subscriptions","organizations_url":"https://api.github.com/users/jimfenton/orgs","repos_url":"https://api.github.com/users/jimfenton/repos","events_url":"https://api.github.com/users/jimfenton/events{/privacy}","received_events_url":"https://api.github.com/users/jimfenton/received_events","type":"User","site_admin":false},"assignees":[{"login":"jimfenton","id":1020212,"avatar_url":"https://avatars.githubusercontent.com/u/1020212?v=3","gravatar_id":"","url":"https://api.github.com/users/jimfenton","html_url":"https://github.com/jimfenton","followers_url":"https://api.github.com/users/jimfenton/followers","following_url":"https://api.github.com/users/jimfenton/following{/other_user}","gists_url":"https://api.github.com/users/jimfenton/gists{/gist_id}","starred_url":"https://api.github.com/users/jimfenton/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/jimfenton/subscriptions","organizations_url":"https://api.github.com/users/jimfenton/orgs","repos_url":"https://api.github.com/users/jimfenton/repos","events_url":"https://api.github.com/users/jimfenton/events{/privacy}","received_events_url":"https://api.github.com/users/jimfenton/received_events","type":"User","site_admin":false}],"milestone":null,"comments":15,"created_at":"2016-09-10T01:15:16Z","updated_at":"2016-12-07T18:10:47Z","closed_at":null,"body":"**Organization**: TeleSign Corporation\n\n**Type**: 2\n\n**Document (63-3, 63A, 63B, or 63C)**: 63B\n\n**Reference (Include section and paragraph number)**: 5.1.3.2\n\n**Comment (Include rationale for comment)**:\nIn analyzing the declaration in 800-63B 5.1.3.2 of “OOB using SMS is deprecated, and may no longer be allowed in future release of this guidance” TeleSign reviewed https://github.com/usnistgov/800-63-3/issues/19 and https://github.com/usnistgov/800-63-3/issues/78. We also reviewed the NIST blog entry discussing the proposed deprecation of SMS at https://nstic.blogs.govdelivery.com/2016/07/29/questionsand-buzz-surrounding-draft-nist-special-publication-800-63-3/. In this blog, the comment that “SMS messages” are being intercepted “en masse” is given as a primary driver behind the decision to deprecate. Following a thorough analysis of this and other cited drivers for deprecation, we conclude the guidance to deprecate should be removed.\n\nIn issues 19 and 78 a good sampling of the exploits against SMS are made. Per the categorization below almost all of these exploits aren’t against SMS inherently but are either Man in the Browser (MITB) attacks, Man in the Middle (MITM) attacks or Social Engineering attacks. While it is possible for Nation States or hackers with special SS7 access to engineer ways to intercept SMS, these types of attacks are extremely difficult to do in some countries (such as the US) and only possible by Nation States in other countries. If the deprecation of SMS is due to the desire to make Nation State attacks a less prevalent threat for second factors of authentication, then the guidance should be altered to only allow second factor authentication on Single or Multi factor Cryptographic devices and software solutions on smartphones should be deprecated. Smartphones broadly are at risk of MITB or MITM attacks. The threats detailed in issues 19 and 78 apply to SMS OTP, but it is clear that these types of attacks can be leveraged against smartphone apps in general. SMS has become a target because it is the most prevalent form of consumer 2FA and has a high attack profile and as such the literature focuses on these attacks.\n\nHacks detailed:\n\n| **Article** | **Threat Type** |\n| --- | --: |\n| Radhesh Krishnan Konoth, Victor van der Veen and Herbert Bos. How Anywhere Computing Just Killed Your Phone-Based Two-Factor Authentication. Twentieth International Conference on Financial Cryptography and Data Security, February 2016. http://fc16.ifca.ai/preproceedings/24_Konoth.pdf | MITB |\n| Collin Mulliner, Ravishankar Borgaonkar, Patrick Stewin, and Jean-Pierre Seifert. SMS-Based One-Time Passwords: Attacks and Defense DIMVA 2013, 19 July 2013. (also slides) https://www.mulliner.org/collin/publications/mulliner_dimva2013.pdf | MITB. (Trojan in article) Suggested solution to this with Mobile OS changes. Also lists various threats to OTP via SMS |\n| \"Warning: Why Most Two-factor Authentication Solutions are Unsafe\" https://www.linkedin.com/pulse/why-most-two-factor-authentication-solutions-unsafe-falk-goossens | Starts with MITM, then talks about MITB. SIM Swap via Social Engineering. |\n| \"Aspect Warns Banks of SMS OTP Vulnerability\" http://mobilemarketingmagazine.com/97087-2/ | Social Engineering. (SIM Swap) |\n| \"'Eurograbber' SMS attack shows Android's vulnerability\" http://www.techworld.com/blog/war-on-error/eurograbber-sms-attack-shows-androids-vulnerability-3537952/ | MITB via Phishing. Malware on mobile. |\n| \"Telcos declare SMS 'unsafe' for bank transactions\" http://www.itnews.com.au/news/telcos-declare-sms-unsafe-for-bank-transactions-322194 | Social Engineering (SIM Swap) |\n| https://twitter.com/kingladar/status/723224164199358465 | Social Engineering |\n| SpyEye Changes Phone Numbers to Hijack Out-of-Band SMS Security ttps://securityintelligence.com/spyeye-changes-phone-numbers-to-hijack-out-of-band-sms-security/ | MITB + Social Engineering |\n| https://www.ftc.gov/news-events/blogs/techftc/2016/06/your-mobile-phone-account-could-be-hijacked-identity-thief | Social Engineering , Identity Theft |\n| http://www.cellusys.com/2015/10/20/8-ss7-vulnerabilities-you-need-to-know-about/ | Hacks in this guide are theoretical as production SS7 networks are highly filtered. |\n| https://www.wired.com/2016/08/hack-brief-hackers-breach-ultra-secure-messaging-app-telegram-iran/ | Social Engineering (SIM Swap) |\n| The cell phone account of the FTC Chief Technologist was hijacked by an impostor using a fake ID. Although the motivation of the attacker was apparently to purchase and resell the phones, it was noted that this could also be used by an attacker attempting to bypass two-factor authentication. The report of the attack also pointed to a New York State website warning against what is called a \"SIM swap\" scam to defeat OOB SMS | Social Engineering (Identify Theft) |\n| Black Lives Matter activist DeRay McKesson had his mobile account hijacked and used to take over his Twitter account, which had two-factor authentication enabled. | Social Engineering |\n\nIn recent disclosures around the zero day Trident-Pegasus attacks (https://citizenlab.org/2016/08/million-dollar-dissident-iphone-zero-day-nso-group-uae/ and https://blog.lookout.com/blog/2016/08/25/trident-pegasus/) it has become very clear that nation states have a rich library of exploits in mobile devices due to secretly known zero days. NIST guidance around use or not of SMS and smartphone second factor authenticators should take this into account. Other technologies that may sit on a smartphone that aren’t SMS like Single or Multi-factor cryptographic software are also subject to MITM or MITB attacks when the endpoint that the cryptographic software is running on has been exploited such that arbitrary root CA certs can be injected onto devices and devices settings can be wholly compromised.\n\n**_Conclusions on NIST’s suggested deprecation of SMS**_\n1.  While SMS OTP vulnerabilities exist, we believe they are difficult to achieve “en masse”. The threat types cited in the documentation apply broadly against all smartphone based security methods in NIST guidance and given this, SMS alone should not be singled out for deprecation.\n2.  Security experts agree, SMS 2FA remains the most viable additional layer of account security for **_the average consumer**_ today due to the ubiquity and convenience of the mobile phone. Having 2FA enabled to protect online accounts is significantly more secure than relying on a username and password alone. We urge NIST to clarify and make distinct how their recommendation does/does not affect the average consumer. Failure to do so willingly perpetuates a perception that “2FA is banned” and other conclusions which are not only false, but also do a disservice to the consumer.\n\n**Suggested Change**: In 5.1.3.2 Remove deprecation of SMS OOB. \n"},"comment":{"url":"https://api.github.com/repos/usnistgov/800-63-3/issues/comments/265525209","html_url":"https://github.com/usnistgov/800-63-3/issues/351#issuecomment-265525209","issue_url":"https://api.github.com/repos/usnistgov/800-63-3/issues/351","id":265525209,"user":{"login":"mschleiff","id":19335518,"avatar_url":"https://avatars.githubusercontent.com/u/19335518?v=3","gravatar_id":"","url":"https://api.github.com/users/mschleiff","html_url":"https://github.com/mschleiff","followers_url":"https://api.github.com/users/mschleiff/followers","following_url":"https://api.github.com/users/mschleiff/following{/other_user}","gists_url":"https://api.github.com/users/mschleiff/gists{/gist_id}","starred_url":"https://api.github.com/users/mschleiff/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/mschleiff/subscriptions","organizations_url":"https://api.github.com/users/mschleiff/orgs","repos_url":"https://api.github.com/users/mschleiff/repos","events_url":"https://api.github.com/users/mschleiff/events{/privacy}","received_events_url":"https://api.github.com/users/mschleiff/received_events","type":"User","site_admin":false},"created_at":"2016-12-07T18:10:47Z","updated_at":"2016-12-07T18:10:47Z","body":"@tonyboo - If we want to talk real world, then it really comes down to what the service provider is willing to accept. Different service providers look at risk differently, and different service providers have differing tolerance for risk, and different service providers have differing options for MFA that they can afford/support/deploy/integrate, and different service providers have differing user populations for which differing authenticators are feasible (or not). So, rather than deprecate SMS, just consider all the warts around SMS and assign it an appropriate assurance score (just like the warts of hardware crypto authenticators and the warts of other kinds of authenticators should be considered to determine their respective assurance scores). Then leave it up to the service providers to figure out what's best for them. "}}
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