SMS is not 2FA-secure
issms2fasecure.com
issms2fasecure.com
Most notably: AT&T and Verizon both use call logs to authenticate SIM swaps from people who don't know the account PIN; requestors are asked to list recently made outbound calls, or in some cases inbound calls. A targeted attacker can trick a customer into making a known call (or, obviously, can simply call the customer to make inbound call records), and then authenticate with them.
AT&T uses billing statement data as a factor. But the research team was able to "spoof" billing statement data by purchasing prepaid refill cards and applying them to a target's account.
The report also identified a bunch of online services for which SMS was used not just as a second factor but, through account recovery, as a sole factor, meaning you're substantially worse off with SMS authentication than you are without it at those services. The reality is probably worse than the report highlights, since a lot of account recovery processes are informal and ad-hoc, and can be socially engineered into relying on SMS.
In fact, Apple should redesign Keychain into a user friendly, 1Password-lite product with 2FA built-in (1Password offers this too) or as a separate app that works with Keychain.
It's bad enough their development toolchain requires you to buy their hardware, now to log into their websites you also have to buy their expensive hardware.
Once you have control over a phone number, you can register iMessage as that number on a device you control.
See: https://blog.elcomsoft.com/wp-content/uploads/2016/03/apple_...
Even if iMessage could be a more secure 1.5FA, it would still be 1.5FA and not true 2FA.
A further cost is that they usually require the user to install and set up an app, contrary to SMS.
This scheme also works really well with payments from your computer. Just use the bank app to scan a qr-code on checkout, verify the payment details on your phone, touch a button, and you're done.
I'd guess that a majority of the bank's clients are using this method. This is in the Netherlands, by the way.
They are precisely equivalent to asking for two passwords on login instead of one password. "Something you know" and "something else you know". So pretty much, yeah. SMS may not be especially secure, but it is at least an actual second factor.
Just wondering if there could be an easier non installed version that was always available.
Apologies if it's a really silly question!
But how do you protect access to the website - with a username and password? Or do people now need to remember another code like "JBSWY3DPEHPK3PXP" to set up the authenticator everytime they visit?
Mobile apps were one way to solve this although the hardware U2F tokens like Yubikey provide another authentication factor in a usable way (and more secure than TOTP because you can't be phished to enter them on the wrong site).
This is more generous than it should be. Your TOTP secret is just another part of your password regardless of whether you personally remember it or not; what matters is that, if I would like to be you, I only need to know the secret.
If it is an account you set up from home, probably the simplest thing to do is print the setup page before you scan the QR code for the secret. Even better, print the page, and then scan that QR code from the printout. Then store the printout where you keep other important papers (e.g., mine would go in my fire proof safe).
Another possibility is to scan the code on two devices. I scan on both my iPhone and my iPad. Nearly all realistic scenarios that involve me losing both of those at near the same time also involve me dying.
Encrypting a file is a bit arcane, but not difficult:
openssl enc -aes-256-cbc -pbkdf2 -iter 1024 -in plaintext.txt -out cryptotext.dat
openssl enc -aes-256-cbc -pbkdf2 -iter 1024 -d -in cryptotext.dat -out plaintext.txt
I prefer one file per code. When I get a new code, I make a directory named after the account the code is for, save a screenshot of the QR code in there, save a text file with the text version of of the code and any one-time recovery codes the site provided. I then make a .zip for .tgz from that directory, encrypt that, and save a copy in the cloud and locally. The local copy is in a location that is included in offsite backups.
If you use one file per code, I'd recommend using a public key system for the encryption. That way you don't have to enter any secrets to encrypt a new code. You only enter anything secret when decrypting.
This has a few advantages.
1. Less chance of accidentally exposing the key.
2. If like most people you use the same key for all the files, no chance of unknowingly mistyping the key resulting in a file that you cannot decrypt later.
3. If you need to recover a code, you only need to decrypt that code.
If as you suggest you wrap this in shell scripts, you can address #2 there. Have a reference file encrypted with your symmetric key. For encryption, the script can ask for your key and verify it was typed correctly by using it to decrypt the reference file.
Also worth considering is using an encrypted disk image. I believe that all major desktop operating systems provide reasonably easy ways to create, mount, and dismount such volumes. Whether you use one file per code or all codes in one file, the file or files can live on an encrypted volume that you only mount when you are saving a new code or recovering an old code.
The advantage of that is that there is no need to use any arcane commands or install any extra software.
I prefer keeping it as simple as possible since the consequences of screwing it up are a whole lot of hassle and possibly being locked out of some accounts forever. One downside is when you add or change a code you have to update all of your backups. A second script that syncs all of the backup files is also helpful to have.
Not to mention Google Authenticator deliberately prevents these stored tokens to be backed up and transferred to a different device, which makes upgrading devices troublesome.
I wish everyone would start using Yubikeys. WebAuthn is now widely supported by browsers.
iPhone backups back up its data correctly—my codes survive new phone restores where they do not with Google Authenticator.
I've wanted to get off Google Authenticator for awhile now, mostly because of the backup-restore problem, also a general trend of limiting my involvement with the company.
It's great that people use can use one app for both factors but it seems less secure than two apps.
For example, use Authy for TOTP and LastPass for long passwords. That's two things that have to be compromised. And both of them allow you to have multiple devices (for example iPhone and iPad).
The biggest thing 2FA protects against is credential stuffing. If you’re using a password manager and have high entropy site-unique passwords, the additional entropy by TOTP is mostly moot anyway.
Passwords - protect against unauthorized access of my service accounts, and 1Password - can be compromised via logging or breaches or just plain peeping
Secret key - acts as 2FA for my 1Password and thus protects my master password from unauthorized use - can be compromised if someone steals the physical paper on which it's stored
TOTP - protect against unauthorized use of my service accounts - can be compromised if someone compromises my mobile phone or phone number. Highly unlikely someone would spend that kind of effort and €€€ on me though
All in all its a pretty nicely tiered system. If someone gets my master password, they still need the secret key. If a burglar steals my secret key, they don't have my master password. If someone somehow compromises both of those, they still don't have access to my TOTPs and thus can't login into any of my 'cricital' accounts (basically e-mail, hosting providers, finance, etc. etc.)
Now imagine you have an malicious spouse or housemate or whatever: they could easily learn your master password by peeping over your shoulder, piecing it together bit by bit (ha). They have a lot of opportunity to search for your secret key as well. If you put your TOTPs on 1Password, you're boned. But if you have them in an authenticator app, even having access to your password manager means jack because they can't login without your TOTPs.
I know one of the big faux pas is to talk about your security but most of this stuff can be deducted pretty easily so I don't feel too exposed.
It doesn't offer export in the app UI. It's not doing anything to prevent you from backing up the tokens yourself; they're stored in the clear in the sqlite database for the app.
If that's too much for you, there's a good chance https://github.com/puddly/android-otp-extractor can get them automatically.
Classic Google Authenticator does not seem much more friction than that.
I am surprised your bank is moving to a weaker auth, what does that mean?
I have 3 bank accounts in 2 countries and they all switched to biometric because it's just a simpler experience then the hardware token or "mobile token" they used before.
Isn’t google authenticator not using this on purpose? Central account and sync is googles thing and yet they deem it too insecure. Completely understandable
So how can using a central service that adds yet another attack vector be of value?
What I would love to have is a paper export. Every time you add a new account to google authenticator you can print it as QR code for later reimport.
Yes many services already provide this for you via recovery codes but having it on a per service basis directly from authenticator is probably much easier to use and not less secure
Any reason this wouldn’t work?
If that were possible then you would face the same problems that reused SMS numbers suffer from.
The website requires a temporary code, generated by a card reader and my card. It works like a 2FA code, as I need to _have_ my card and to _know_ its pin.
Recently however it has become somewhat less strict it feels[0] and I can now log in to my bank app using FaceID or a pin code.
Normal bank websites still demand a code from a hardware token (think RSA key, but with a pincode and sequence-based instead of time based.)
[0]: I realize it might be that they are just as strict only doing more work in background to verify me instead of bugging me.
https://techcrunch.com/2014/02/27/apple-explains-exactly-how...
But if in those cases you disable SMS auth, then you can't recover your account right? That might be considered worse off in some cases.
I mean, in Europe if criminals want to get a bunch of stuff on credit from some place with a disposable identity, they generally recruit poor/homeless people with real IDs, because that is simpler/cheaper/safer than trying to do it with counterfeit IDs.
SMS hijacking, just as the core identity theft issue is so much rare elsewhere - it demonstrates that it's a solvable issue if the USA wanted to solve it. (in some sense the discussion on identity theft reminds me of https://www.theonion.com/no-way-to-prevent-this-says-only-na...) However, the straightforward way to do that would require a proper single centralized (i.e. federal) gov't ID issued to almost all people, which seems to be anathema in USA.
A few years back I have lost my phone and went to get a new SIM. The attendant in the shop only had a quick look over my ID card. He didn't scan it nor did he enter the ID number in the computer to check anything. I think he only verified that the name was the same as the one on file and the photo looked like me.
The same happens at the post office when you go to collect a parcel / registered mail.
On the other hand, in almost every bar I've been, staff would do a quick check with a pen on every 50 € note they would get, and those notes are fairly common (two cocktails in a random bar in Paris can often cost more than 20 €). I don't know how effective that is in actually detecting counterfeit bills, but there's clearly more effort that what the other clerk did.
This forces crooks to use more expensive and traceable high quality papers for their counterfeit notes or they'll get rejected in stores and bars.
Having IDs that actually look up to anything at all is a relatively modern idea. When I was born if you suspected a passport in my country of being bogus it'd probably take a bunch of clerks several hours of physically looking through filing cabinets to check.
And where we build systems that can check often people don't. The UK government built a system which lets a driver prove to the government who they are and then get a token value back which they can give to anyone - that token can be exchanged for viewing the government records for that driver. So e.g. hire firms could insist on this token to see you're not disqualified and actually have the entitlements your physical driving license says you have.
They don't. Some of them will let you give them this token reluctantly but all prefer you give them a print out, which obviously you could just fake.
Can you detail which "most" of Europe you are talking about?
In Italy, while obviously you have to produce an ID card, there is no way that it can be checked online by "an employer", only Police (and Carabinieri) can do those checks, and of course ony for Italian issued ID's, moreover in some other businesses besides SIM card selling where the ID is needed (as an example hotels, AirBnB's and similar, car or tools renting, etc.) the actual employee never had a formal, official training to recognize forged ID's so everything is demanded to the single employee common sense and experience/knowledge (often zero or next to zero).
Particularly with "foreign" or "uncommon" pieces of ID's even if Italian (besides the "normal" ID cards and passports there are a number of other documents that have ID value) it is extremely difficult to understand if it is forged.
In UK AFAIK there is no national ID card, so you are limited to passport and/or (if valid for the scope) the driver license.
For the record - for a period it was laminated, and then it was forbidden to laminate it (as forgeries were somewhat simpler with the laminated one, though I don't know the details).
Old ID card (paper, large, duration - theorical - 5 years, then extended to 10 years, practically indestructible, i.e. they actually lasted the 5 or 10 years):
https://carinola.modulisticacomune.it/modulistica/categorie/...
New ID card (electronic, credit card size, with chip[1], duration - theorical - 10 years, usually illegible after 2 or 3 years in a wallet unless you use a protective cover):
https://www.formatrieti.it/carta-didentita-elettronica
And whether you get the one or the other may depend on the city (comune) as most will use all the empty paper documents they have in storage before starting issuing the new electronic format.
[1] for which noone or nearly noone has a reader BTW, the whole stuff is somehow experimental, even now that we have an app (Android only):
https://www.cartaidentita.interno.gov.it/identificazione-fis...
The US also has the REAL ID[0] standard that requires IDs to meet minimum standards in order to be accepted by the federal government.
If carriers just required a REAL ID compliant ID in order to get a new SIM, and actually checked it via the chip or magnetic strip, I think we'd be good.
Which is usually a really crappy idea when you want to save a few bucks compared to a real passport.
They're umpteen stories of heartbreak and hurt, by people not being allowed to board an international flight, or a cruise which stops at destinations not covered by a passport card.
They're also those that thought it's a great idea to get them for their kids.
With the same consequence. A passport card does not allow you to fly internationally. Not even to Mexico or Canada.
I'm not saying use it for international travel, I'm saying use it as an ID? Literally any American citizen can get an ID card for $65 that is accepted everywhere someone asks you for ID.
If we started taking things a bit more seriously, we could also get that fee down by subsidizing it.
Unless it's the former it's as good as a standard paper ID as far as forgeries go. If anything, having it machine-readable decreases security as it means the person inspecting it spends less time looking at it and just scans it in a machine.
That is for example how my debit card works. If I want to use it abroad I have to turn that feature on for whatever time I am abroad.
The same is true with my major US bank (and probably other banks too).
[0] Full disclosure: I work at Twilio and built the first version of the wireless product, so I'm a bit biased.
Also, remember the date when you created your Google account. The best way to find that date may be to look at the first email you received in the account.
This just moves your security issues to another account.. how many layers of recovery email address are you willing to go before hitting the end?
This is how it works in Poland since September 2019, after some recent SIM-swap attacks. You can swap SIM or get a replacement if stolen only at store showing government ID. It is free of charge with Orange and not always free with T-mobile.
But this has some downsides in real life.
1) I had to walk my 88 yo Mom to the store to swap SIM card.
2) Every clerk at every shop can do that so for a determined criminal it is possible to bribe or threaten one.
3) Virtual operators (MVNOs) usually do not have physical locations and there is a dozen of them.
Your first drawback is substantial, though.
That would be smart criminal with means. I was thinking more of a hood with fat neck passing $20 to clerk assistant to obtain SIM for $5k fraud.
https://arstechnica.com/tech-policy/2019/10/att-employees-he...
So easy for evildoers and so much friction for law-abiding customers.
A recovery code snail-mailed/e-mailed to the account holder when they first open the account is the correct way to go, and if they can't provide it they need to go through a lengthy process where many factors are used to authenticate them (verify their physical address, verify their ID, ask to confirm last call records, billing details, etc).
If later it turns out this was a sim swapping attack you can verify if the clerk entered a valid document ID. He can’t do that without having been presented a proper document, so you can tell if he checked.
I wasn't sure how would you solve the problem of verifying the ID card without showing the previously recorded number to the clerk. But simply requiring to every time just punch in the ID (and maybe scan the whole card to check the photo later) could work - if the system only returns a big OK or BAD signal.
Currently here, in Hungary, the clerks just photocopy the IDs though. And there was a big scandal a few years ago (in connection to the ISIL/ISIS attacks in EU) about some groups obtaining hundreds of thousands of SIMs for just a few names.
Won’t this work?
This is a terrible scheme.
Edit: regarding the "lack of availability" at the point of wanting to reset the password: the urgency of resetting passwords should be considered a lesser inconvenience than the risk of having lost control of your account through insecure 2FA.
(I am simply supporting my original brain storming thought through ... I am not married to this idea in any way or form. Just a thought.)
On top of that, one could think of: A passphrase to authenticate a number transfer to another sim.
Sending a code through physical mail.
Do you know if something like this exists in europe?
After that 2FA should always be device specific. If you want to do 2FA with your phone then the 2FA challenge should not get sent via an identifier like a phone number that may change owners. Instead you should download a 2FA app that generates a private/public key pair where the public key is linked to your account. That way the only thing you need to do is wipe your phone remotely if it gets lost.
- There are online-only providers. E.g. Giffgaff in the UK, Mobile Vikings in Belgium, etc. - Many European countries offer prepaid SIMs that aren't tied to ID. Instead, you can just buy them in the supermarket the same way like you would a gift voucher.
Not saying I like this or that this is good way forward but it's a reality that contradicts your assumption.
Offtopic: those laws seem kind of silly if you can still get a valid SIM for 10 days without any ID. Seems more to be about surveillance than about anti-terrorism.
0: https://www.nbcbayarea.com/news/local/mans-1m-life-savings-s...
1: https://www.kaspersky.com/blog/ss7-hacked/25529/
I thought both these vectors were already common knowledge to HN readers.
One person can't know everything... that's why I come here. Thanks for the info!
If people knew how telcom (and the internet) was held together with bubblegun and duct tape...
Multiple proposed fixes and replacements to SS7, to the best of my knowledge none of them are going anywhere. And even if it was pushed hard, it has to be a global thing.
* Bidding doesn't happen in real time, but you can tell carriers your "rates" so to speak.
https://www.kaspersky.com/blog/hacking-cellular-networks/106...
Carrier license sounds much more involved than what it is. It's not uncommon to sell full SS7 access to companies that are not operators in the regular sense.
- Stingrays...
- Operator app pushes to SIM cards...
- Secret GSM processors and software internals
- Voice / text / data "ciphering"
- Protocol-level "emergency" tracking features
- Silent SMS (sounds like its from a bad cop show but its actually a real thing it turns out.) "They do not show up on a display, nor trigger any acoustical signal when received. Their primary purpose was to deliver special services of the network operator to any cell phone." -- sounds like it has a completely legit use...
The list goes on. It's enough to make anyone want to get the tin foil out. But at least in this case there's a simple and clear recommendation: --not to use 2-factor auth by SIM--.
The original purpose of silent SMS was to send voicemail or missed call notifications to handsets, which would trigger an icon to be displayed on the device. Sending a regular SMS would be annoying as the user would have to delete it - after you've listened to your voicemail, another silent SMS can be sent to turn off the notification. Also originally SMS was stored in the SIM itself which had limited memory, so it would be not be very convenient if you didn't receive a voicemail message as your SIM was full. Remember this is a 28 year old feature of GSM.
The tracking argument seems somewhat mute, maybe when this first came to light 10 years ago it wasn't the case, but nowadays I would be very surprised if operators do not keep detailed logs of all the IMEI (unique identifier for a given device) and IMSI (same, but for the SIM) that connect to their towers.
Scary thought
This happened both by government-linked parties, where they are able to coerce providers to do it, mostly targeting prominent political opposition members. It also happened without government involvement, done by provider's personnel with sufficient access and some entrepreneur attitude.
The rule of thumb to protect against it:
- do not use SMS 2FA
- if you do, use a foreign SIP number with SMS capabilities
- if you HAVE to use local sim, use SIM that belongs to someone else and noone knows you use it
Any good providers? I've tried Twilio SMS forwarding, but different services (e.g. Steam) reject it for 2FA since they're pretty much considered throwaway numbers, I suppose there's some sort of blacklist
Shitty 2fa will still deter people who get a list of a hundred million emails/usernames and passwords and try them on banks, Twitter etc from putting in the extra work to break into your account specifically.
If you expect targeted attacks - from governments, because you oppose them, from determined criminals, because you have a lot of nice stuff to steal, or from people around you, because you know too many assholes - maybe it might as well not exist, but for most people, most of the time, any 2fa is better than none.
Because with 99.99% certainty the person that needs to unlock the account is me, and not an attacker.
Even with a dozen backup yubikeys and spare codes written down I’d still be much more likely to lock myself out than be attacked.
If it’s one thing I have learned the hard way it’s that the most dangerous person in the equation is myself. I won’t trust myself with any kind of security.
If you need a blood sample, then would donating blood be considered compromising security?
Identity is what your DNA is. Password is a secret. Your DNA is not a secret.
I will agree with "you have to be physically present" is good enough password. This is Yubikey, which works fantastic. The problem with DNA is when it is compromised - you can't throw it away/change it without exorbant effort (bone marrow transplant? and then you're simply taking on someone else's identity? is that identity theft?).
[0] https://www.quora.com/Do-we-require-live-cells-when-extracti...
Which I agree, that works great, but quite narrow in the the use cases at that point.
Carriers have already demonstrated their complete across the board failure to have appropriate security procedures. Your DNA isn't hard to find, you leave it literally everywhere you go.
And do you really want mobile carriers creating a DNA database of their every customer? The same companies that already sell your location data to bounty hunters?
That's going to be a big no thank you from me.
Any port-out requests are handled manually - you are contacted by a human to ensure that you made the request. You can ask them to put a verification code on file for you to confirm when this happens if you're concerned about the security of your XMPP account (which itself could use whatever kind of authentication scheme you like).
There is also work being done to update the type field of JMP numbers so they appear as "mobile" instead.
Type field is interesting. Not sure this can pass the radars for too long though.
Anytime you have a human in the loop you have the risk of human failings. I.e., that human forgets to follow critical step X in the protocol. Or that human falls for the attackers emotional sob story and takes pity on the attacker and lets the attacker unlock your account. Or that particular human is amenable to bribery to obtain the outcome the attacker wants.
In fact, many sim swaps have been reported to have occurred because of "human at cell phone store did not follow protocol" or "human at cell phone store was taking bribes".
So having a human in the loop is not an absolute solution to solving the problem.
I'm not sure you get this. Google hasn't seemed to get this in the past. They have added some customer support though.
This is exactly my point. If the risk of an attack is X, the risk of me being that person who fails or forgets a critical step of the protocol (backup yubikey, whatever) is a hundred times higher. So this system of “flawed humans interacting” to me looks like the lesser evil.
I don’t want my things protected by foolproof protocols. I‘m the fool you see.
That's why I'm bullish on things like Shamir's Secret Sharing and other social recovery tools.
So I've been working on a backup plan. Current incarnation is to use a simple Go cli tool with Shamir's secret sharing algo to break a password into N/M shards. The user can then do whatever they please with the shards, give some to their family, friends, attorney, make a pirate map, get an rfid chip, anything you want.
They can meet at the funeral to assemble your horcruxes.
I am not sure this is true. Most people regularly get phishing e-mails and apparently fall for it.
SMS and TOTP (due to the window of time the TOTP code is valid) only provide limited protection against active phishing attacks, since phishing site can 'proxy' the the SMS/TOTP code besides the password.
I think I would prefer losing access to an account (since I make backups of critical stuff anyway) than my account getting compromised, which could lead to identity theft/fraud, etc.
It doesn’t mean that for the rest of the world SMS 2FA is completely secure, it’s just a lot more difficult (or impractical/impossible) to do a SIM swap so easily. As mentioned in another comment below, SS7 vulnerabilities are another attack vector, globally available and without requiring a SIM swap.
Of course there are much better 2FA options, but for the general public, they are probably too complicated to use.
Everyone understands SMS.
Hint: if a store ask for a phone number to get a discount, try the local areacode then 634 5789. This is from an old song, and many people seem to have created "anonymous" account with it!
Obviously banks are a place with a lot of low-value targets and a few very high-value targets, but the cost to implement MFA is the same so they might as well do it.
In my strictly personal opinion, responding to a notification that asks if a login attempt is you is clear enough that people need minimal training to make use of it. This might just be me, though.
In my career, I've definitely seen people actively choose SMS over other factors on offer. It was easier for them, and in many cases shouldn't have been offered. Your point about SMS being better than nothing is wise and true and insightful, but it's perhaps not always the question as faced in practice.
Your experience and standards of clarity may be different from mine, obviously.
In all these situations, I've found companies which offer a back up SMS option very valuable since it usually gets delivered.
Unless you're using HOTP to mean HOTP and all extending schemes.
I tend to use TOTP for systems where I'm concerned about offline usage. But again, YMMV.
It uses the SIM to implement a challenge-response mechanism where a PIN is prompted by your phone. While not perfect, it's vastly better than using SMS, without being less convenient.
I don't know if other places leverage the fact that SIMs are smart cards which are perfectly able to perform this kind of stuff given the proper infrastructure.
The only difference is that you need to register your SIM with the service beforehand, using a reasonably secure process. Banks make you use their own MFA before you can enable Mobile ID (and no, it's never over SMS).
if you get a SIM replaced after providing proofs of identity, residence and biometrics, it would get activated after few hours.
The kicker is that it wont get SMSes for 24 hours after the SIM is activated.
In the US, won't it be cheaper as well as secure to get a virtual phone number from Twilio for purposes of two factor authentication? (In India, there is no service at the rate what Twilio offers, but there are some which charge around $30-$40/month for virtual phone numbers with incoming SMSes)
The word "secure" is not binary.
sms as a 2fa is secure.
Just not as secure as a authy totp account
...which is not as secure as a unclonable totp system
...which is not as secure as a hardware token based otp system
...which is not as secure as a hardware token that also requires you enter a pin and a fingerprint to activate it and only communicates using hard coded encrypted messages with the legit service that issued it.
Your website is outsourcing security to any company which can service a cell phone account, which may be better than your website security or worse.
Always buy two. ;-)
Joking aside, I've moved almost every 2FA to hard token, soft-token, or google voice. But the root of trust is still LastPass & Google. I don't see an easy way out of dependency other than power of attorney. Even worse: I worry what happens to my protected assets as I age and possibly face memory loss.
No place you store your backup can guarantee it won't be lost or destroyed.
I got bitten in a bad way!
Hopefully twilio will start creating "recognized" numbers someday, as my twilio number is unusable for TOTP. There seems to be a blacklist of all twilio voip numbers.
google's enhanced protection requires you to have 2 distinct yubikeys to sign up
The question is "Is SMS 2FA secure?", not "Is SMS 2FA-secure?" There is no such property as 2FA-secure.
Title should read: "SMS 2FA is not secure".
The only problem is there are very few services that get it right. Get it right means support multiple tokens and allow to truly disable any other means of logging in or recovering the password.
Most services seem bent on allowing many ways of logging in without giving a choice. For example, they will advertise they use 2fa tokens but then if you can't produce one they will still allow you to log in with SMS or mail (ie. password recovery by mail). Facebook will not even let you set up tokens without having SMS set up as a factor and the phone number verified.
I hope slowly developers will get more aware and they will be better tooling (and stack exchange answers to ctrl+c ctrl+v...) to do it correctly.
https://play.google.com/store/apps/details?id=com.google.and...
Otherwise, you can just grab a few backup codes out of your fireproof safe and register your new totp code, or go to the bank and get them out of your bank vault.
Sure, the fireproof safe costs as much as a few yubikeys, but if you go the yubikey route you both need the yubikeys and a fireproof safe and bank vault for your spare yubikeys too.
Or a password manager file only for TOTP backups.
When you take something from envelope, note the date, the why, the number of envelope you opened and the number of envelope you then put the piece of paper in. Every time you open envelope check with the register that the numbers agree.
Unfortunately my bank (ANZ) and my government's online platform (myGov) in AU both have dedicated OTP apps which only allow single-device installations. When I lived overseas, my bank in Germany also had their own dedicated OTP app but they allowed installation on a backup device as well. Much better.
I THINK it's chase, but I'm not sure.
They have my correct phone number, but for years now, the code just... never shows up.
As for email being unencrypted, I think most of it now is encrypted during transit (thanks to the Big Two providers knocking points off a spam score if a message does come via TLS) and even if it weren’t the password is also not known so the second factor is not useful. For example, I just tried to log in to chase.com and the code they emailed me at 1752 MST is 067315.
If I’ve been phished so hard that posting this is useful, again I’m screwed.
Is SMS 2FA enough for most of the people today? Yes
Is SMS a cost-benefit solution for most uses? Yes
It’s free, and requires a tiny bit of additional configuration to enable. No reason not to offer it.
Configuring the seed, remembering an extra password to use the OTP... For me it's not that hard, but probably my mom will need some help in order to remember all the steps...
I know some services require SMS in order to force collection of user’s phone number, for data selling purposes and to prevent bots.
With large enough numbers, you'll see everything, but you don't even need large numbers to get people whose lives are made more difficult by technology.
This, coupled with a "I know what I'm doing, never let support reset my password" option that disabled changing the user's password for anyone without direct write access to the production database was pretty good for security, I feel.
It great for keeping people using scripted attacks against a huge list of accounts. It isn’t really to keep people specifically after your account out.
If somebody wants your shit and specifically your shit.... they’ll get it...
How? I don't think Brian Krebs has been hacked, even though he's extremely targeted by hackers (his site is literally the benchmark for performing DDOS attacks on).
How do you protect against an insider attack?
But its not just LinkedIn. Its a huge list of major companies including some FAANG ones too. Oh dear.
You should be worried if you are a POI or you are being targeted personally. And if it is so, SIM Swapping it's just one option and if it doesn't work there are other methods (breaking in, stealing yubikeys, mobiles...)
They still ask for a phone number when applying to jobs through their platform. I always put zeros or random digits in the field and put the real one in the resume.
We are never going to get the benefits of digital identity until the government wakes up and brings its services into the digital age.
Anybody with direct access to SS7 can send a fake roaming request for your sim card.
It's a complete shitshow. Occasionally syndicates manage to get both sides of 2FA lined up (insiders) and clean out someone's account.
Then the bank says not my problem - you didn't keep your password safe. And the cell provider says not my problem - not intended as security mechanism. Leaving the customer poor and sht out of luck.
https://security.googleblog.com/2019/05/new-research-how-eff...
Consider this scenario. Twitch now enforces the use of all accounts that want to stream all require the use of 2FA, after the whole artifact fiasco. Anyone over the age of 13 is able to do this. I don't expect everyone at this age to have a phone number, and I assume these people would rely on their parents phone to pass this.
As authy is completely optional, people may choose to not require another app for their account, in effort of just quickly jumping through another hoop blocking them from going live, or the device owner not wanting to have an app installed.
It just feels weird knowing that this can be a point of failure for a service that solely relies on a single 2FA method that could from an attack like this down to the individual and how they operate.
Even login.gov supports it!
https://www.slashgear.com/chrome-is-adding-touch-id-and-fing...
The device is first enrolled, the website gives the device a secret value which the device can put in its secure element. When needing to authenticate again the device checks biometrics locally and if correct then the secure element releases the secret value which is then either passed onto the website or used as part of a challenge-response authentication.
This means if you lose or reset your device you can't get back in despite having the right biometrics.
Yubikey has the same problem you describe. If your key stops working, you'd also be locked out. Yubikeys can spontaneously stop working in my experience.
To mitigate this, sites like login.gov allow you to add multiple devices, so you can have it on e.g. your laptop and your phone, and yubikeys if you'd like. I generally do all three for important sites (or multiple Yubikey when touchID is not offered).
Anyway, my point is that offering TouchID makes a more secure 2FA very, very convenient for the average person. I'm just surprised more developers haven't offered it even though it's been in Chrome for a couple years.
Using a few old Google accounts, I experimented with Google’s account recovery options and discovered that if a Google account does not have a backup phone number associated with it, Google requires you to have access to the recovery email account OR know the security questions in order to take over an account. However, if a backup phone number is on the account, Google allows you to type in a code from an SMS to the device in lieu of any other information.
[1] https://tech.vijayp.ca/adding-a-phone-number-to-your-google-...
If you change your SIM card you'll have to reset your 2FA setup on the banks site. It's done on the carrier side.
I still hate it tho, as you are locked to a phone number and it sucks when you move countries a lot.
Websites used weak hashes (md5 and sha1... efficient to compute and attack) to store passwords and allowed users to set short, weak passwords (12345, letmein).
Long passwords randomly generated by password managers and stored as strong hashes (Argon2id) by websites are secure, not guessable and even difficult/expensive to attack offline when the database is dumped.
This approach is simple and easily understood by everyone involved (users and site admins) and would be suitable for the security of 99% of websites. Leaving 'Account Recovery' as the only remaining challenge.
Facebook Messenger uses a phone number either tied to your Facebook Account, or identified as the phone number on your mobile device, to immediately log you into a Messenger account, with zero authentication. They literally ask you "Is this your account?" and you just click "Yes" and you are in that account. Even if it's not yours.
If you use prepaid phone numbers, or link one to your account, you can often get into Facebook Messenger accounts that aren't yours.
You want your: bank, utility provider, entity-that-has-lots-of-personal-data-on-you to offer other secure options.
This might be a costing issue though. When your customers number in the millions, your call center is probably handling thousands of "im locked out" issues per day and these need to be handled in x-minutes. Other security options might cause the time meant to handle these scenarios to increase and SMS is generally 'simple' compared to them.
(FWIW, SMS is also insecure in that it's fairly easy to passively snoop on SMS comms, but that's a separate problem.)
Support does this to 'verify your identity' and authorize doing arbitrary things like even moving $100,000 out of your bank account.
And no, their security team won't fix this.
I knew it had to be a scam, but hadn’t put the pieces together.
There is no option to turn it off.
AFAIK, they were hacked using plain simple SIM swap/cloning.
The amount of knowledge one needs to port a phone number is unbelievably little, and peoples very nature to be helpful works against us. Up until maybe just very recently you needed the account number of the phone number and the last four of a social security number... sometimes, just the account number. Also, the last four of one's social security number is perhaps the shittiest way to authenticate _ANYTHING_. For many years, a lot of sites online would show you the last four of an account holder's SSN (and some places still probably do) if you have an email address, correct name, and phone number or physical address.
Getting the account number would likely be even easier thanks to helpful store reps... Just go in and make up an excuse why you need it or forgot it, it's like "social engineering 101" because it seems so benign to most people. You already know the name, address, and phone number-- you just "forgot" your id at home... Or one could just listen to them call each-other write down their info and then call another store.
With those two things in hand, the phone number is pretty much the attacker's, and getting it back would take more than enough time for extensive amounts of damage... ESPECIALLY if that is the only line on the account (or they took all the lines)... I'd guess a bare minimum with near immediate recognition of the real problem (your number heisted) and police involvement, probably a minimum of ~12 hours.
So, if phone numbers are so bad why are they ever used? IMHO, that's because they aren't to provide security, they're to provide easy tracking between your virtual life and your physical one. You're only securing the businesses data pipeline, not your personal data.
If you want 2FA (and everyone should) use Google Authenticator or a Yubikey... or whatever I'm not trying to shill brands just ideas that work.
The paper mentions some websites that claim to use SMS 2FA, but actually use SMS as a single factor for password resey. While that's really bad I think the solution is to fix those broken implementations not to stop using SMS 2FA everywhere in favor of using nothing.
According to this paper, t-mobile has the smallest surface area, which is sad.
Would it be less sad if it was Verizon?
After all, most have a spare phone and great use for those Nokia's.
In describing the set they initially drew from, it seems like they've described the 17 redacted sites simply by describing their complementary set (the 128 sites that are secure).
Long answer: nooooooooooo.
https://en.m.wikipedia.org/wiki/Betteridge's_law_of_headline...
My vote would just be not to vote (neutral). There is certainly more (in)appropriate stuff to downvote.
But this one felt more like it would be something a little deeper.
So then I clicked through - and the page fills up with the word “no”.
So I feel pretty duped.
Honestly I think the headline is attention grabbing. A much more useful headline would have been “An analysis of the vulnerabilities of 2FA over SMS”.
But the Betteridge headline is in the domain name!
>You are consenting to be contacted at the phone number selected for the purpose of receiving an authorization code. If you selected text message, Wireless and text message fees may apply from your carrier. Supported carriers include: Alltel, AT&T, Cellular One, T-Mobile, Virgin Mobile, U.S Cellular and Verizon Wireless.
Although I just remembered this person on Hacker News replied to me 1+ year ago that their Google Voice number does work with BoA 2FA SMS, so maybe it's just my specific GV phone number?
Getting access back to her account took a bunch of steps, including adding her current number.
The interface for FB really makes it seem like you might lose access to your account if you don't provide them with your number. Even better is that FB exposes a small list of your friends (and the total count) of everyone who has given them their phone number.
tl;dr: Don't add your phone number to FB.
Better than not having it? Yes.
Better than committing a 4,096Kb PK to memory and confirming all interactions with mental arithmetic? No.
I happen to think the benefits of SMS 2FA, even when working as intended, are negligible. It seems like a bad idea to waste the finite amount of developer good will we have asking services to implement it.
Literally the only attack that SMS 2FA has any impact on is credential stuffing, and even then it's debatable. Credential stuffing is using the credentials stolen from one service to compromise another. If you don't reuse passwords, then you don't need SMS 2FA.
If you do reuse passwords - then it seems impossible you're not also vulnerable to phishing. After all, you're already willing to hand over your credentials to anyone who asks. SMS 2FA is not a solution to phishing, as the tokens themselves can be phished.
2FA requires you to have 2 factors at the same time. e.g. When I log onto amazon from a new browser with valid username+password it additionally requires me to confirm via my phone number.
1or1FA (e.g. reset your password via SMS if you forget your password) is just increasing the attack area on 1FA (would be more secure without it).
Problem it's trying to solve, is that it's conventionally unacceptable to lock people out of their accounts.
Under what circumstances does the phone number prompt prevent the attacker from accessing your account?
Perhaps they used phishing? Then they can just phish the SMS code as well.
Perhaps they're a MITM over an insecure channel? Then they can just wait for you to enter the SMS code.
Perhaps you installed their malware? Then they can just inject some code into the browser.
TL;DR: don't.
Feels like some kind of spammy PageRank manipulation going on. I'm happy to be wrong about this, but I wanted to see if anyone else has noticed. Maybe I'm just smoking crack waffles again.
It's a single-purpose domain name, so the Name of the domain is the same as the Name of the content on the domain.