the PayPal pot calling the Apple Pay kettle black

so if you haven't heard yet, PayPal took out a full page ad in the New York Times trying to drag Apple Pay's name through the mud based on Apple's unfortunate celebrity nude selfie leak. This despite the fact that PayPal happily hands out your email address to anyone you have a transaction with. In essence, PayPal has been leaking email addresses for years and not doing anything about it, so they shouldn't get to criticize others for leaking personal information.

what's the big deal about email addresses? while it's true that we often have to give every site we do a transaction on an email address, we don't have to give them all the same address. in fact, giving each site a different email address happens to be a pretty good way to avoid spam, but more importantly it's a good way to avoid phishing emails, and that's important where PayPal is concerned because PayPal one of the most phished brands in existence.

unfortunately, because PayPal wants all parties in a transaction to be able to communicate with each other, they do the laziest, most brain-dead thing one can imagine to accomplish this: they hand out your PayPal email address to others, which is pretty much the worst email address to do that with. i have actually had to change the disposable email address i use with PayPal because they are apparently incapable of keeping that address out of the hands of spammers, phishers, and other email-based miscreants. furthermore, i also use their service less because i don't want to have to clean up after their mess.

at some point i may have to start creating disposable PayPal accounts and use prepaid debt cards with them. certainly if i were trying to hide from massive spy agencies then that would be the way to go, but if i'm only concerned with mitigating email-borne threats i really shouldn't have to go to that much trouble. there are other, more intelligent things that PayPal could, even should be doing.

• they could share the email address of your choosing, rather than the one you registered with their service unconditionally. that way you could provide the same address you probably already provided that other party when you created an account on their site. it shouldn't be too difficult for them to verify that address before sharing it with the other party since they already verify the one you register with.
• they could offer their own private messaging service so that communication could be done through their servers (which would no doubt aid in conflict resolution).
• they could provide a disposable email forwarding service such that the party you're interacting with gets a unique {something}@paypalmail.com address that forwards the mail on to the email address you registered on PayPal with, and once the transaction is completed to everyone's satisfaction the address is deactivated.

they don't do anything like that, however. here's what you can do right now with the facilities PayPal makes available. it's a more painful and less intuitive process than anything proposed above, but it does work.

1. before you choose to pay for something with PayPal, log into PayPal and add an email address (the one you want shared with the party you're doing a transaction with) to your profile. PayPal limits you to 8 addresses.
2. confirm the address by opening the confirmation link that was sent to that address
3. make that address the primary email address for your account
4. confirm the change in primary email address (if you have a card associated with your PayPal account, PayPal may ask you to enter the full card number)
5. at this point you can use PayPal to pay for something and the email address that will be shared with the other party is the one you just added to your PayPal account
6. once you've paid with PayPal you will probably want to log back into PayPal, change the primary email address back to what it originally was (and confirm the change once again) and then remove the address you added for the purposes of your purchase. the reason you'll likely want to do this is because PayPal sends emails to every address it has on record for you, and those duplicate emails will get old fast.

most people aren't even going to be aware that they can do this to keep their real PayPal email address a secret from 3rd parties. as a result all manner of email-borne threats can and eventually will wind up in what would otherwise have been a trusted email inbox. make no mistake, this isn't PayPal providing a way to keep that email address private, this is a way of manipulating PayPal's features to achieve that effect. there are too many unnecessary steps involved for this to be the intended use scenario.

as such, PayPal is leaking a valuable email address by default every time you pay for something. yes Apple's selfie SNAFU was embarrassing to people, and yes if Apple doesn't do something about that now that they're becoming a payment platform it could be not just embarrassing but financially costly for victims, but PayPal is already assisting in similarly costly outcomes right now (not to mention potential malware outcomes) so they really have no right to be criticizing Apple. Apple, at least, is taking steps to correct their problems - what is PayPal doing?

economics of 2 factor man-in-the-middle phishing

by now i would hope that most people reading this blog are aware that 2 factor authentication doesn't protect against phishing...

over on the symantec security response weblog, zulfikar ramzan concedes very much the same thing, that man-in-the-middle phishing can compromise even 2 factor authentication schemes, but puts it into a broader context and states that the 2 factor authentication still changes the economics of the attack and effectively makes it less profitable...

you see, the world of cybercrime is one where information is frequently bought and sold and the one-time passcodes generated by security tokens used in 2 factor authentication schemes are supposed to prevent your credentials from being traded like a black-market commodity... as such, the theory goes that the phishers, rather than having a salable good that they can pawn off on someone prepared to actually use the information, are only able to access the compromised account login sessions directly and so have to be prepared to get their money from the victims directly... this is a riskier proposition and therefore seemingly less valuable to the phishers...

although it may seem like the credentials the phisher captures are useless for resale, i'm not entirely convinced they are - credential re-use being what it is and with the heightened sense of security that the tokens offer, i'm sure those usernames and passwords will often be useful on sites other than the ones using the 2 factor authentication systems... moreover, i'm not convinced that the economics of the attack are changed as much as one might think, or that there isn't a comparable salable good to be offered here... if pornographers can monetize live video feeds of young women in various states of undress then i don't see why phishers can't sell real-time access to the login sessions they've compromised, perhaps even by setting up their customers as mirrors for the phishing page(s) and using load balancing to direct the appropriate proportion of phishing page requests to those customers' mirrors depending on how much the customer paid (and those customers could in turn resell the sessions in exactly the same way their provider sells them)...

2 factor authentication certainly changes the phishing landscape, but to say that it will reduce profitability assumes the bad guys can't innovate (which is a pretty bad assumption to make)... one simply has to imagine new ways to do things, and criminals are already familiar with imagining new ways to make money...

security tokens don't protect against phishing

you never know when you're going to come across a train of thought so thoroughly wrong it deserves to be debunked... that's what i learned today (hey, i haven't gone to sleep yet, it's still officially today) when i read david maynor's blog entry where he mentions thinking that with a paypal security token he won't have to worry about where he enters his paypal credentials anymore...

gold star if you're shaking your head just thinking about that... security tokens, generally part of a 2 factor authentication system (where you prove who you are using something you know, like a password, and something you have, like a token), won't protect you against phishing - at least not completely... the simplistic phishing attempts that we're familiar with right now would be thwarted by 2 factor authentication but not only can the practice of phishing adapt to 2 factor authentication it's already started to do so...

phishing schemes using man-in-the-middle attacks have already been spotted in the wild and some specifically support 2 factor authentication...

the reason phishing is possible is the same reason man-in-the-middle attacks are possible - one end of the communication (in this case the phish site) hasn't been authenticated... you can strengthen your own authentication until you're blue in the face - even 3 factor authentication won't help you if you don't know for sure that the person you're talking to really is who they claim to be...

site authentication is a hard problem, though, a lot harder than people give it credit for... as i've said before, site authentication schemes that work by placing something on an authentic site to prove it's authentic won't work very well because we just aren't all that good at noticing when something is missing (which it theoretically would be for a fake site)... i also don't understand what's so special about things like site authentication images that prevents them from being spoofed by a man-in-the-middle attack as well - the attacker's system should be able to pull the proper image from the real site so long as it sends the same identifying information to it that the client normally would have...

sender authentication isn't quite as hard a problem, though... perhaps david should read my post about avoiding phishing emails the easy way so that he can harden up that soft spot he has for paypal phish...

why 'safe site' indicators fail

there's been some interest lately in a study on the efficacy of various 'safe site' indicators such as HTTPS and website authentication images... these are indicators that are supposed to help the user determine that it's safe for them to enter their credentials, that it isn't a phishing site, but according to the study those indicators don't work (or rather their absence isn't enough to tell people that a site isn't safe)...

let's look at why... website authentication images (where you select an image to be shown on future visits to prove that the site is the same one you initially visited - essentially a visual shared secret authentication protocol) are a pretty new development, their use (and their significance) has probably not yet reached the mainstream among users... as such slip ups might be forgiven (if you could attribute a near 100% failure rate to mere slip ups)... maybe websites are just too unreliable when it comes to displaying images - perhaps we've come to expect images to be absent on occasion...

HTTPS indicators (that indicates you're visiting a secure site, that your session is encrypted with SSL or TLS) on the other hand have been around for quite some time... they've become about as mainstream in the publics awareness as they're going to get so their complete failure can't be blamed on it's novelty - perhaps they're just too unobtrusive?

the only one that had a significant impact was actually an unsafe site indicator (a warning that came up when visiting a site that wasn't safe)... now, aside from the interesting implications all this may have for why humans seem to more naturally lean towards blacklists, the relative success of these 2 types of indicators (safe or unsafe) brought to mind a little tidbit about human perception i heard some time ago... it seems that we're much better at noticing when something that shouldn't be there is there than we are at noticing when something that should be there isn't...

put another way:

The opposite to this effect is a situation where the brain perceives something that is not actually there. On being presented with an incomplete object, the brain automatically fills in the missing pieces according to our previous memory and experience. There are many examples available of common optical illusions to illustrate this.

this more than adequately explains why the absence of safe site indicators would be ignored by people, and in so doing shows why such human-interpreted safe site indicators aren't (and won't be) effective at warning people away from phishing sites...

(and yes, i realize the implications this has for my manual phishing email detection method - i can only hope that our tendency to pay attention to who sends the emails we receive makes share secret authentication as a way to weed out phish more workable in an email context than it is on the web...)

phishing alarmism

there's a new post over on the securiteam blog that seems to be just a little too concerned about a bank of america suggestion to add an email address to customer's address books... the author seems to believe that following the suggestion will make customers more vulnerable to phishing, that the bank is asking them to lower their defenses...

now, it's not like they're telling people to lower the security settings on their browsers in order to view the bank's website (though perhaps they do that too, i don't know), they're just telling their customers to whitelist them so that their emails don't get rejected by spam filters... the author's contention is that phishers will then start using the same address the customers whitelist as the From: address on their own phishy emails and because the address is whitelisted the customers will be exposed to each and every one of those phishing emails...

but here's the thing, even if bank of america didn't advise their customers to whitelist the email address, the phishers would have used it anyways... phishers posing as bank of america will use any address bank of america uses, regardless of what customers do with that address... there's nothing bank of america can do to stop that and there's nothing customers can do to stop that so it makes little difference whether the customers whitelist it or not... whitelisting the address doesn't mean they can start implicitly trusting email apparently sent from that address, it just means that bank of america's legitimate correspondence won't get lost in the junk mail folder...

of course the phishing emails won't get lost there either, perhaps that's the problem? unfortunately, spam filters aren't really any good at stopping phishing emails... the phishers work hard to make their emails look legit (otherwise they wouldn't fool anyone) so they should be equally affected or equally immune to spam filters as the legitimate bank of america emails are... if the legit emails get through then so will the phishing emails, and if the legit emails don't get through then the users will have to look in their junk mail folders for them and then wind up being exposed to the phishing emails anyways...

basically it's a zero-sum situation as far as phishing goes - nothing the legitimate sender or the receiver do with the From: address can increase or decrease the exposure to phishing so the bank of america customers might as well whitelist bank of america's email address - and security folks might as well wake up to the fact that just because something can be used to a phisher's advantage doesn't mean the user is put at greater risk... spam filtering and anti-phishing are not the same, even though we don't want to see either spam or phishing emails in our inboxes, defenses against one are not necessarily appropriate or applicable towards the other... the officially whitelisted email address just means the phishers don't have to work so hard to figure out what email address to forge on their phishing emails - their convenience does not equal lower security for others...

(and if you're wondering why this isn't a comment on the securiteam blog, it's because i can't leave comments there anymore... they've been consistently rejected as spam for months regardless of content, email address used, or the presence of a url - and the blog admin who's supposed to be alerted to the comment in order to correct the issue if it was misclassified never does, nor is there any obvious way to follow the directions which say to contact him/her about it... they sure know how to make a guy feel welcome...)

how to recognize phishing emails the easy way

perhaps you've seen this phishing iq test before... if not, that's ok - it's basically a bunch of examples of legitimate emails and phishing emails and you have to try and figure out which are which... the root concept is that there are these heuristics or rules of thumb that you can apply so as to determine whether a particular email is phishy just by looking at it...

the fact that browsers now come with anti-phishing technology built in that tries to identify a phishing site just by looking at the URL is strong evidence that those rules of thumb for detecting phishing emails are a failure but take the test and look at some of those rules at the end and see if you can determine why those rules aren't going to work... if you ask me, those rules are just too complex for the average person to remember or apply... add to that the fact that the characteristics of a legitimate email are possible in phishing emails (for example, ebay starts their emails to you with your ebay user name but anyone who has interacted with you on ebay knows that user name and thus has the information necessary to make a convincing fake ebay email)... finally take into account that legitimate emails often display phishy characteristics (both in the test, where only one of the emails was completely free of phishy characteristics, and in this real world example) and it becomes clear that not only are the rules complex but they're pretty much completely unreliable too...

after getting through that test, if you're like me you're probably saying to yourself "there must be an easier way"... so you can imagine how glad i am that i don't need to try to remember and follow those screwy rules... instead, i do something i touched on in my spam avoidance article - i use disposable email addresses... now, while the spam avoidance techniques actually apply to pretty much all forms of email annoyance (if the bad guys don't know your email address they can't send you bad email), i'm actually talking about more than just keeping my email address out of the hands of phishers, something that works even when your real email address is known to the bad guys... i use unique (a different one for each site) unguessable disposable email addresses provided by sneakemail.com and then when i get an email from ebay or paypal or my bank i check and make sure that it was sent to the right address for that organization...

here's how the magic works - let's say i create an address like mgbwklw02@sneakemail.com and give that address to ebay and no one else... the address is a secret that only ebay and myself know and no one else can guess so when i get an ebay email sent to that address i'll know that it was sent by ebay because they proved who they were by using a secret known only to ebay and myself... it's like knowing the secret passphrase or handshake to get into an exclusive club (or, more technically, it's like a shared secret authentication protocol)... alternatively, if i get an email supposedly from ebay but sent to some other email address i'll know it's fake because it was sent to some address that i never gave to ebay in the first place... if someone really, really wanted to send me a convincing fake ebay email they would have to either guess exactly the right email address to send to or guess the label i gave my ebay address (sneakemail.com allows you to label your disposable addresses and includes the that label in the From: field to help you determine which address the email was sent to) and try to forge a sneakemail.com header...

could using unique unguessable disposable email addresses for sites/organizations and ignoring emails sent to the wrong address for the site/organization in question qualify as an anti-phishing safe hex rule? i think so... although it requires a little more work up front (creating a new address each time you create an account somewhere), it's conceptually simpler than the multitude of rules currently being suggested and it's a lot more reliable too since it doesn't depend on questionable criteria such as how the email was composed...

what is pharming?

pharming is a phishing enhancement technique that manipulates domain resolution (by changing the victim's hosts file or by DNS cache poisoning) in order to make it impossible to recognize a phishing site just by looking at the URL...

by this i mean that when the victim visits the phishing site it will have the domain name of the site that the phishing site is impersonating... in fact, when the victim tries to go to the legitimate site, whether by typing in the URL from memory or using bookmarks or other legitimate links they will be redirected to the phishing site instead...

while some of the simpler phishing attacks may disguise the phishy nature of a site by using URL tricks (such as URLs with @ symbols in them, or URLs that are simply close to the legitimate URL or contain the legitimate organization's name in them), pharming disguises it at the network level so that even anti-phishing toolbars and technology are unlikely to detect the attack... that said, pharming is a more difficult form of disguise to pull off than simple URL trickery...


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what is phishing?

phishing is a form of identity theft where the victim is enticed (typically by means of a message of some sort) to use what appears to be a legitimate logon page for some service (like online banking or paypal or ebay) but is actually a fake page designed to capture identifying information (like credit card numbers or login credentials) that enable the perpetrators to fraudulently pose as the owners of that information...

like email scams, phishing is usually about getting your money; however, unlike email scams where you are convinced to hand over your money, phishing just tricks you into revealing the information necessary for the phisher to take your money him/herself...

also like email scams, phishing is a form of social engineering - usually you're given some compelling reason to visit their fake logon page such as giving you the chance to undo a transaction that you never actually made or making mandatory updates to your account information...

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