I'm always concerned about the security of services I use. I'm even more concerned since security breaches have been happening more and more lately, and they always generate a lot of noise in the media.

Now I'm already trying to secure my accounts to the maximal amount possible, like using 2FA wherever possible and using a strong password manager. However these measures won't protect upon security breaches.

Is there a somewhat reliable method to detect security breaches before they are announced so I can act and don't have to react?

Optional bonus question: What steps can I take to ensure security of my data in case there's an unannounced breach?

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    Today we are expecting a shower of unsalted passwords. Tomorrow is partly cloudy with a 5% chance of SQL-injections. No but seriously if it would be easy to forecast companies would be doing it already.
    – John
    Commented Mar 3, 2016 at 14:07
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    @John, I want the forecast in between when the attack has taken place and when it has been announced by the company. Not forecast it three days ahead.
    – SEJPM
    Commented Mar 3, 2016 at 14:08
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    I see. Using different email-addresses per account from a provider that allows you to monitor attempted logins could be useful.
    – John
    Commented Mar 3, 2016 at 14:10
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    @SEJPM This isn't answer-worthy so I'm posting as a comment. I use a site for detection for some of my free emails called: haveibeenpwned.com. While this won't give you that "magic" detection you're seeking, it will help show you if you've registered on a site and they've had a security breach. I know it's after the fact, but what I use it for is to see if some site I registered for years ago and forgot about or haven't used since registration has been hacked and my creds therefore compromised. If you're practicing good security and not repeating passwords and using randomly... Commented Mar 3, 2016 at 15:58
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    @DeerHunter or you could be proactive and hack all the sites. Then you will know they have been breached.
    – emory
    Commented Mar 3, 2016 at 17:44

5 Answers 5


You can't detect it with 100% certainty because not everyone who steals your data wants to phish you, or sell it. But for those who do want to phish you - and that's a large portion of them - there are some tricks you can apply.

In most places, you cannot provide fake details. You need to enter your name, physical address, credit card information, social security number, etc. You don't really have much control over the real details.

However, what you do have control over is your email address. You can always provide a dummy email account to anyone, for any reason, even if the rest of your details are required to be legitimate.

Roving Email Address Method

Let's call this REAM. I like REAM.

Here's what I do: I buy a few domains and create unlimited amounts of email addresses, then use a different email address for each website on which I have an account. I also use Gmail, Yahoo, etc.

Buy 2-3 reasonable domain names, and give the accounts reasonable, unique names like [email protected], [email protected], etc. You can also use free email providers, but having to repeatedly enter your phone number might cause you some issues.

It's a lot of work, but it pays off in the long run. When you're asked for your email address at a retailer, give them one of those emails, and use it ONLY for them. Make sure you use each email address only once. Carry a list of email addresses in your wallet.

Now why would we want to detect phishing, instead of sending it to the spam folder? Because a phishing attempt on these emails may indicate a breach.

I've found that, with astounding regularity, without even providing my email address to additional companies beyond the first one, that I get phished on a regular basis on each account. In fact, I've seen dozens of such breaches.

Here's a small list of some notable phishing attacks I've found:

  1. OPM (2011, undisclosed until 2015)
  2. IRS (2015, undisclosed until late 2015)
  3. IRS (2016. Repeat of 2015? Undisclosed until recently)
  4. Pizza Hut (early 2015, breach still undisclosed)
  5. Target (2013?)

In most of the emails, the attackers usually have bad English. In some, they do not. They'll also google a location near the provided address, and say they have a job opportunity, etc.

In some cases, I will even get phone calls from them in the same area code as me! It's actually very easy to get a burner phone at Wal-Mart and have it set to the same area code as your victim. If you're clever enough, and they're in the same country, then you can quickly lead them down the path of the damned.

In nearly every case, they try to get me to click on an infected website. I will go there anyway (on a dummy+virtual machine, obviously) because I am a masochistic security researcher who revels in reverse-engineering malware, and making attackers suffer. Suffer mortals as your pathetic magic betrays you! You may not want to visit them, however.

The Multiple Phone Number Method

Some like to try and use multiple phone numbers. I would not do this. It's neither reliable, nor effective because:

  1. Phone numbers can be enumerated very easily, and auto-dialed/texted.
  2. It costs a lot of money to have multiple phone numbers.
  3. You'll likely get calls from people who knew the person who knew the previous owner.

Therefore, REAM is a much better way than this.

The Plus Email Address Method

I guess we can call this PEAM.

Others have suggested the plus email address method. Gmail supports this. For example, if your email address is [email protected], it's recommended to use [email protected] instead. Google will apparently discard the plus side of the email address.

Using this method could be good for a lot of reasons. However, very few - if any - of those reasons would apply to actual skilled phishers. I would not recommend using this method because it may only work against run-of-the-mill spammers, not actual skilled phishers. Here's why:

  1. Phishers are more intelligent than the average spammer. They are targeting you personally. If you respond, they will build a profile on you, or maybe they already have a profile built on you based on stolen data sets.
  2. Spammers are willy-nilly sending spam to everyone they can. Your plus addressing still gets delivered to your inbox. And you just know you want those lengthening pills... so you end up buying them anyway, and they don't work, and all the women laugh at you. [sobbing uncontrollably] Ahem...
  3. This method can be easily circumvented with code. I'll demonstrate:

    List<String> possiblyIntelligentTargetList = new List<String>();
    foreach (string email in emailAddressCollection)
        // We might've found a plus-size individual
        if (email.Contains("+"))
            // Ignore the plus email address
            string realEmailAddress = email.Split("+")[0] + "@" + email.Split("@")[1];
            // Phish user's actual email address.
            // Add their provided email to a new list so we can analyze later

    Of course, this could be made much better, but this is a rough example of how easy it would be do to this. It only took me like 0.05 miliseconds to write this.

With the above code snippet, the plus side of the email address is discarded. Now how will you know where the breach came from? Because of this, I would recommend that you get REAMed.

Trawling the "Deep Web"

bmargulies brings up an interesting, and very good point: your data may sometimes appear on the Deep Web. However, this information is usually for sale.

While yes, it may be possible to detect a breach before it's announced by visiting the Deep Web or using an Identity Protection Service that does, this method has it's drawbacks as well. Here are a few problems I see with looking on the Deep Web:

  1. While some Identity Protection services are excellent, they may cost a fair bit of money. Identity protection services may be provided for free, but they usually come after the breach announcement, and the protection only lasts for a limited time, usually around 1-2 years.
  2. You usually have to buy this information from attackers, unless they released it for the Lulz.
  3. The breached data simply may not appear on the Deep Web at all.

As you can see, there are a lot of pros and cons of every single method here. No method is perfect. It's impossible to get 100% perfection.

REAM also detects individual breaches

This method doesn't just detect breaches to companies. It detects breaches to individuals. You may find that, after giving someone your email address, they send you phishing attacks several months later. It may come from them, or it may come from someone else who hacked them.

Now that my data has been stolen, what do I do?

If you have a strong suspicion that your sensitive information has been stolen, you should do the following:

  1. Shut down and replace all credit and debit cards associated with the aforementioned email address.
  2. Put a freeze on your credit so they can't do anything with the details.
  3. Inform the company/individual that they've likely been hacked, so they can take the appropriate steps.
  4. Read about Virtual Credit Cards in the answer provided by emory for the bonus question below.
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    I respect your tinfoilery which in general is stronger than mine. However, there is room for improvement. I use shop safe which is a kind of virtual credit card. If I am making a purchase in October for $100, the credit limit on the card is $100 and the expiration date is November. After the payment is processed or November, the credit card info is no longer sensitive. I don't need to shut down and replace all cards associated with a hacked site.
    – emory
    Commented Mar 3, 2016 at 15:02
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    @MarkBuffalo my credit card company provides ShopSafe as a service to me. If they are breached, then I am hosed. It is one account, one physical card, and an unlimited number of credit card numbers with customizable credit limits and expiration dates. ShopSafe also records the first merchant to make a charge against the virtual card. If anyone else tries to charge against the card, they are rejected. ShopSafe is just the brand name my credit card company uses. The general concept is virtual credit card and your card may already be providing it.
    – emory
    Commented Mar 3, 2016 at 15:20
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    @mucaho With REAM, and if phished, you can tell if your personal information was breached or not. How else would the attackers know to phish that one single email, used in only one place, unless they had already dumped the database contents? This information helps you take appropriate steps to protecting your data before the companies release information on the breach. Some companies/agencies/universities/etc don't even know they've been breached, or they won't even disclose it years down the road. For example, with Pizza Hut, I'm still waiting for the announcement! Commented Mar 3, 2016 at 16:22
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    "Carry a list of email addresses in your wallet" -- or allow delivery to any address starting with "michael.duncan2017", and give out addresses like "michael.duncan2017.pizza.hut@", that you can improvise as needed (and later block if needed due to spam). This is a lot like using the feature "[email protected]", except that I benefit from a little bit of obscurity in that spammers and phishers know everything after the + in a gmail address is insignificant, whereas they don't know my mail delivery rules :-) Commented Mar 3, 2016 at 16:41
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    @MarkBuffalo "With REAM, and if phished, you can tell if your personal information was breached or not" - not true. With REAM you can tell if your personal information was breached. It will never tell you that your personal information was not breached. I still think it is a good idea.
    – emory
    Commented Mar 3, 2016 at 17:01

For the main question, I recommend Mark Buffalo's answer.

For the bonus question, my credit card company provides me a virtual credit card service they call ShopSafe. Other credit card companies provide their own virtual credit card services that will have different names and different details. Here are the ShopSafe features.

I can create a virtual credit card at will in a matter of seconds using their web portal. I can choose the credit limit and expiration date. Any charges against this virtual credit card will show up on my regular credit card bill as if they were against my regular credit card. I can query for charges against specific virtual credit cards.

When I need to provide credit card information, I create a virtual credit card with a chosen credit limit and expiration date. If I am buying a $100 item in October, the credit limit is $100 and the card expires in November. If the site is breached, most likely my credit card info is stale. This covers the majority of use cases.

Another use case is my transit pass. I have a transit pass that allows me to ride buses and metros. I have provided the transit agency with a virtual credit card. Every time my transit pass drops below $20, they auto-reload it (by charging my virtual credit card).

I gave the transit agency a virtual credit card with a $500 limit and 12 months until expiry because I want the card to auto-reload by itself. (When I am running for a train, I don't want to spend time adding money to the transit pass.)

ShopSafe records the first merchant to charge against a virtual credit card. Subsequent charges made by other merchants will be automatically rejected. If the transit agency is breached, my virtual credit card will not be expired and it will have credit left, but nonetheless the hackers will not be able to make charges against it. No one but the transit agency can charge against that virtual credit card.

Without a Virtual Credit Card If you do not have virtual credit cards, then you might make all purchases with the same credit card number. If a site gets breached (and even if you know about it) you will probably choose not to cancel the card because it would disrupt everything else. Instead you would probably rely on your credit card's fraud guarantees. As hackers put bogus charges on your card, you dispute them. The credit card company is exposed to financial risk.

So virtual credit cards are mostly a benefit to your credit card company. If they do not make it available to you, their heads are full of rocks.

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    Are you affiliated with "ShopSafe"'s issuer company? Commented Mar 3, 2016 at 17:11
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    @Mindwin I am affiliated as a user.
    – emory
    Commented Mar 3, 2016 at 17:23
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    I used to use a service like that. I loved it until a baseball team wouldn't let me pick up my tickets at Will Call because I couldn't show them a credit card matching the number I used to buy my tickets (it got sorted out eventually but took a while).
    – user15392
    Commented Mar 3, 2016 at 19:26
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    This is an excellent recommendation. I've completely stopped using my real credit card number for any online purchases. Any time I buy something, I quickly create a new virtual credit card with all the details, set the limit a few dollars above the purchase price and use that. This actually saved me on one occasion when one of my email accounts got breached - the thief only got an already-used / expired CC number.
    – xxbbcc
    Commented Mar 3, 2016 at 20:09
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    @E.P. I know similar services are available in the UK, Portugal, and Egypt. Other than that, I have no clue.
    – emory
    Commented Mar 4, 2016 at 17:17

Facebook scrapes popular pastebin type sites where hackers post stolen login info and checks for their users' account info. You could do the same (for your various email addresses or credit card numbers), though it'd be a lot of work!

To do this, we monitor a selection of different 'paste' sites for stolen credentials and watch for reports of large scale data breaches. We collect the stolen credentials that have been publicly posted and check them to see if the stolen email and password combination matches the same email and password being used on Facebook


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    Essentially this is one of the services haveibeenpwned.com provides. Commented Mar 4, 2016 at 21:26
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    @NeilMcGuigan I see now, I thought it was restricted to facebook. I took a second look at it and it is a very good service. I was not trying to be argumentative. I just did not see the value at the time.
    – emory
    Commented Mar 4, 2016 at 23:18

I like Mark Buffalo's REAM method, but in reality it's too cumbersome for most people, so I'll give a better alternative: plus addressing (aka address aliasing, virtual identities).

Instead of creating several email accounts, you can have a single account, but multiple email addresses.The best news is that, if you use Gmail, you already have everything you need.

In practice

Let's say your email is [email protected], and you want to give your email to SomeCompany.

You can provide [email protected], and it'll be routed to your account - anything after the + is ignored.

Some websites won't let you have a + in your address. Feel free to let them know that they are in violation of RFC5322 section 3.2.3 and the internet police will come and fine them. If they don't believe in you, for some reason, you'll have to resort to more...

Underhanded tactics

Provide them with [email protected] - still the same address (as far as Google's servers are concerned). If you know how to count in binary and have a email with 11 characters, you can get 1024 different addresses this way.

I can count in binary, but it's a pain

You might just as well invest a couple of bucks in your own domain, a book about Exim, and some caffeine. A lot, actually. Then, besides plus addressing, you can have minus addressing, multiply addressing, dollar addressing, or whatever suits your fancy.

Spammers / phishers are not stupid, they'll remove the plus

Please let the dozens of scammers hitting my domain know.

Some particularly bright chaps actually wrote a parser that thinks [email protected] is actually [email protected]. Truly genius.

If you are savvy enough to use a plus on your address, it's probably fair to say you won't fall for a mass scamming operation, so writing a parser to address it is likely a waste of resources for people doing that.

That is not to say, of course, that you won't get targeted specifically if you are a high-value target. If you're that concerned, just use your own domain. The way the address is parsed is entirely at the discretion of the MTA, so there's no way for the sender to actually know what they should parse out.

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    If I'm writing malware to phish people, the first thing I'm going to remove/filter everything that has plus addressing. ;-) Commented Mar 4, 2016 at 1:17
  • Do you think spammers are stupid enough not to know that [email protected] and [email protected] are the same address? Commented Mar 4, 2016 at 7:56
  • @DmitryGrigoryev - no, but I do think they're LAZY and are very unlikely to hand-sanitize a large stolen database of email addresses. Commented Mar 4, 2016 at 9:20
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    @JamesSnell hand-sanitize? I think it is safe to assume that spammers know at least some Perl. Commented Mar 4, 2016 at 10:13
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    Regarding sanitising addresses, it's pretty trivial to set up your email so that "sanitised" addresses won't work. Tell all your friends that [email protected] is your address, and funnel everything that comes to [email protected] into your spam folder. Spammers who know that this is possible realise that attempting to sanitise an address without knowing the recipient's mail rules might make it less likely to work. Commented Mar 4, 2016 at 14:38

There are various 'identity protection' services you can pay for. Amongst other things, they troll the dark web for your email, credit card, etc. Everyone exposed in the OPM breech gets one of these for free. If you are really concerned, you might decide that one of them is worth the cost to you.

Of course, as pointed out in a comment, there's no guarantee that your information will turn up where they look.

However, I'm a bit perplexed by the focus on email addresses in other answers here. It's not hard to avoid phishing. I've never seen a phishing email that even momentarily threatened to mislead me. I gave up on protecting my email address a long time ago; I find that Google correctly spam-folders 99% of the phishing I get, and the rest, as above, is not hard to spot.

If someone has a breech, they might leak your email. Your bigger worry is that some set of idiots failed the PCI test and have leaked your credit card number. You can invent email addresses all day long and it won't help you with these cases.

  • The identity protection services can be good, yes, but not everyone posts your data on the deep web, and those who do usually try to sell the info before providing it. Will the identity protection services purchase data from hackers? Different hackers have different motivations for that data, and if someone else contacts your fake email, then it's bad news. The focus on email addresses is shared as a way to detect phishing attempts, not avoid them: nobody should be emailing you at that email address to begin with except the company. If they do, it usually indicates something very suspicious. Commented Mar 5, 2016 at 15:46
  • The question asked, 'how to detect a breech'. Detecting a phishing attempt is interesting, and even useful, but its not quite the same thing in my jaundiced view.
    – bmargulies
    Commented Mar 5, 2016 at 16:13
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    I think you are misunderstanding the question. The OP wants to know how he can possibly detect a breach before the breached company announces it so he can protect himself instead of waiting for the company to tell him his data has been stolen. While yes, the Dark Web may contain information on these breaches eventually, and the information may only be available if someone pays for it, I've found that a lot of phishers attempt to attack my dummy emails before the information even ends up on the deep web, if it even does. Commented Mar 5, 2016 at 16:18
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    Even though I feel you missed some points, I'm giving you a +1 for your input. It's very welcome. The Deep Web / Identity Protection Services was a good addition, and I've now updated my answer to address it. Commented Mar 5, 2016 at 16:31

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