270

Privacy. Being able to link every user account to a natural person would be the end of anonymity on the Internet. Maybe you have nothing to hide, so that's of no concern for you. But as Edward Snowden said: "Arguing that you don't care about the right to privacy because you have nothing to hide is no different than saying you don't care about free speech ...


177

As you said, you saw this on facebook - so I tried these steps: Login with lukas@gmail.com and real password -> works Login with lukas@gmail.cmo and real password -> works, too (!) Login with luksa@gmail.com and real password -> also works Login with luksa@mail.com and real password -> also works Login with lukas@gmail.cmo and wrong password -> Wrong ...


172

Lots of examples. A high-profile and recent example is when Kanye was caught on camera entering his "00000" password to unlock his device. Shoulder-surfing is one reason why applications do not display the password text on the screen, but show ****** instead. And this is one reason why multi-factor authentication is so important; even if you know the ...


114

Many people have looked at the reasons not to allow name changes from both a security and a community standpoint. However, there are plenty of legitimate reasons to allow username changes, even if the username is separate from the display name, for example: Someone has changed their real life name or the name by which they'd prefer to be called, due to ...


74

It depends entirely on what you mean by "safe". If your only concern is an attacker guessing URLs, then 16 alphanumerics gives roughly 8,000,000,000,000,000,000,000,000 possible addresses, which is plenty to stop random guessing -- in order for an attacker to have a 50% chance of finding even one picture on a site with a thousand users in a year, they'd ...


71

Your question is missing a lot of context, but what you do say sounds like you’re looking to settle an argument. So my answer will start with “It depends...” One reason to have unique usernames that aren’t email addresses is to protect privacy when other users can see the username. For example, GitHub profiles indicate the username in the profile URL, and ...


70

A harder to guess username adds to the security if it's kept secret. The problems are Usernames are often not kept especially secret. On most systems allowing multiple users to log in, any user can view the list of valid users. On systems that run mailservers, the mailserver can effectively be used to check if a username might be valid as most mailservers ...


55

In some countries, it is simply forbidden to use the most important unique IDs in other databases than those for which it was originally meant for. For example, you would get an ID for the state-run health insurance system, which the tax office is not allowed to use and vice versa. All this to ensure privacy and make it more difficult to cross-reference ...


55

As another example, here are some images from KrebsOnSecurity on ATM Skimmers (devices used to steal ATM credentials) Hidden camera behind ATM faceplate (source) Hidden camera glued to corner of ATM (source) Hidden camera on fake panel of ATM (source) So yes, it is a very real-world concern.


34

I would say as long as they are not able to change their unique identifier. I.e. they can change the name they show up as, but that name is tied back to an unchanging user ID number (this will make your DBAs happier too). I'd also make sure user's couldn't change their name to an old name of another user (to help mitigate the scam potential Anders is talking ...


33

Yes, it is bad security practice indeed. When using the Forgotten Password feature, the site should respond with a message: "An email has just been sent to the specified email address, if it exists and is registered within our system. Please read the email and follow the instructions." Or simply: "Please check your email inbox for instructions on how to ...


33

No. A username is not supposed to be kept secret and thusly won't be. A username is a public ID. Relying on it for security is not smart.


31

The short answer is that it is very, very likely that your concatenated username and password exist on an unencrypted log somewhere that a larger group of people would conceivably have access to than the restricted logs. You are not paranoid to change your password and should change it when this happens.


30

There are two main arguments for enforcing requirements/restrictions on username choices. The first is that making usernames more difficult for attackers to predict helps resist online guessing attacks. While usernames aren't necessarily considered to be as secret as passwords they are one of at least two pieces of information that must be stolen to ...


24

Maybe not the answer to your question, but if you would like to "hide" the location of your profile pictures on a website, you could just embed the image as data URIs. You can base64 encode the image on your server and embed the string on your website, instead of exposing any image paths. see http://css-tricks.com/data-uris/ and http://css-tricks.com/...


24

Since you already brought up dropbox, I think we can give at least one reason why doing this is a bad idea: Dropbox disables old shared links after tax returns end up on Google The flaw, which is reportedly also present on Box, impacts shared files that contain hyperlinks. "Dropbox users can share links to any file or folder in their Dropbox," the ...


23

The username is not a secret; any determined attacker will be able to find out the names of users on your system. What does improve your security, is if there is no remote access for "root", "guest", and similar account names found on many systems. In fact, Ubuntu explicitly disables the "root" account because it is such a favorite target.


20

As well as security, there are also colossal privacy concerns. You probably don’t want Facebook and Pornhub to be able to compare notes and link your Pornhub account to your Facebook account. And of course, someone might want to create two different accounts, but they’ve only got one ID.


19

E-Mails are in fact used for user identity on many websites. There are advantages and disadvantages to this. An incomplete list: Advantages the problem of uniqueness is solved already no need to come up with or invent a username you don't need to ask the e-mail address additionally Disadvantages people do sometimes change their e-mail address it often ...


17

Actually we have a very pertinent case in point as to why this is not a good idea. In the US, we have long had a system of credit reporting that is based on national Id. The (absurd) presumption was that if you know the national Id of some person and their name, birthdate etc., you must be that person. The problem with this is that finding out the the ...


17

Also, there have been cases reported where thermal imagers were used to extract a PIN or password from a keyboard just used to enter it - the hotter a key, if time of finger contact is about equal (heat soaks in...), the more recently it has been pressed. This might not present the password on a silver platter due to duplicate keys, different finger dwell ...


15

There's a reason few websites follow that "security" measure: you lose usability (and users) without gaining any security. Any website with even the smallest hint of security will enforce a limit on the amount of times you can "guess" a password OR a username, to prevent people iterating over all of the existing usernames. This limit needs to be imposed on ...


15

But if this happens my password would be stored in some unencrypted log somewhere, right along with my username. Is this a reasonable concern? Yes. Am I being too paranoid? It depends. If your worry is about the password being stored, then absolutely you're not. Your password will get stored in the clear to a near certainty. Being aware of ...


15

Allowing username or email iteration may be a security problem for most sites, but not for Facebook. For sites as large as Facebook, finding emails that have accounts is easy because the sites have so many users. This holds for other huge user databases like Google and Microsoft. These companies just have to be secure in the face of their username/email ...


15

That sucks. I can't think of any other possible solutions beyond the ones you listed: 1) Keep at the technical support to delete the account (fully delete from all databases). This is probably your cleanest option. 2) Go around changing your password everywhere. I recognize this is a pain, and impractical / impossible for websites that you don't remember ...


13

Something that may help: Get into the habbit of "pressing" a few buttons in addition to your password. Say, your password is 1234. You could hit the 1 and 2, pretend to press, say, 9, and then continue your password. It discourages any cameras, key-wear down, or onlookers. It's certainly low grade, yes, but it deters people who have 1000 other clips of ...


12

The other answers are generally good, but another consideration is the transport. If you're using plain http or any other non-encrypted protocol (or sending the urls via email), all data you transmit and receive, including these urls, should be considered completely public from a security standpoint. A large portion (anyone have stats?) of users are on ...


11

These user names requirement can cause user names to be less predictable. I don't think that this provides a substantial security improvement, but I can think of a couple of scenarios where they help a little. I doubt that it offsets the loss of usability, but I lack concrete evidence to conclude. As usual, security at the expense of usability, comes at the ...


10

It depends on the type of application. If it's a forum, it makes sense to add another layer of usernames for a couple of reasons: Mask the e-mail address from public (you need to have a display name, and many people might not want their e-mail address to go public). Though, another option would be to make people login with their e-mail address, and give ...


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