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In the past I have completed an 'anonymous' survey at work only to find that my employer was able to garner a lot of not-anonymous information from this survey. Location, name of manager, etc. None of this information was provided in the survey. This leads me to believe that somehow the website has been able to identify some form of user information.

Is there a way that a webpage can read user or other system related information? The site in question has aspx and js elements.

I cannot think of any other way they could identify the user. The link doesn't appear unique. Browser is IE, environment is Win7 on Citrix.

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36  
You do know when you do an "anonymous" survey, and the invite link kinda looks like a unique generated link, that it might not be 100% anonymous? or if you have to login or such, schools do that quite alot. – Lighty Mar 7 at 10:57
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Approximately 200 people got the same email with the same link. There is no login or any other form of identifying questions asked anywhere in the survey. – iShaymus Mar 7 at 11:00
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Was the survey hosted at your intranet or was it on a server of an external company? If external, did it use https? – Philipp Mar 7 at 11:51
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As a general rule of thumb you should assume that nothing you for a company will be anonymous. – David Grinberg Mar 7 at 14:14
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If there are free-form textboxes then the amount of detail which you provide in your answers can easily identify you. "What do you like least about your job?"..."I really find it irritating that so many people abuse the smoke-break policy."..."Hmm, lets pull up a list of everyone that has complained about smoke-break abuse in the past year.".."Hmm, this person also mentions their contribution to the Penske file."..."Must be Constanza!" – MonkeyZeus Mar 7 at 15:36
up vote 89 down vote accepted

If the site is based on ASPX files, then it is more than likely that this is a ASP.NET application - most probably hosted on IIS.

IIS has a very simple checkbox to enable Windows Integrated Authentication.

IE, on Windows 7, will by default send your credentials to any web server in the local intranet. (This is not your password, don't worry, but it is Windows based authentication - either Kerberos or NTLM).

This is very straightforward to associate your Windows Domain account with your survey answers...

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and that is even besides the fact that it is rather easy to deanonymize you based on your answers and knowledge of you personally... – AviD Mar 7 at 11:32
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This seems very much the likely answer. Several intranet webapps automatically detect you as a user without a logon requirement. – iShaymus Mar 7 at 12:35
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@iShaymus I really hate when "smart apps" cross into the "smartier (sic) than thou" territory. Because most often than not, they aren't. – Mindwin Mar 7 at 12:54
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@Mindwin I really hate it when someone says something is anonymous but in reality it's anything but... – iShaymus Mar 7 at 13:03
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@iShaymus that says a lot more about your company, than about any specific app... Trust is hard earned, and easily lost. Once broken, near impossible to repair. – AviD Mar 7 at 13:42

That's incredible simple, and a really old trick.

Create a different survey for each department, even if the surveys have the same questions.

  • Everyone that answers to Survey X is from Department A.
  • Everyone that answers to Survey Y is from Department B.

Then, you just need to mash up the results and you're done!

That alone is enough to do a lot of information gathering, without any special tricks.

Brazillian banks did something similar, on paper surveys - each manager was to distribute to his subordinates copies of the survey. However, each manager got his copies on paper of a different color - so everyone that answered the yellow copy was from RH, everyone that answered the blue copy was from Finances, everyone that answered the pink copy was from Sales, and so on. Even if you didn't ask for the employee department, name or registry number, you knew from where he was and in what department he worked.

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20  
I doubt you need to even go to that much trouble. How many African Americans do you have working for you? If the answer is 1 and ethnicity is a survey question, then you broken anonymity. If you have a large number of African-American employees, then how many African-American, female employees working in the Finance Department? – emory Mar 7 at 14:05
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In support of @emory's point, for several years I was the only female Computer Science PhD student over age 50 at UCSD. I looked at a lot of surveys and found I would be in a group of size one. – Patricia Shanahan Mar 7 at 17:45
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Shameless plug for a research group in the same department as my old graduate group: privacy.cis.upenn.edu They are doing research on formal guarantees of differential privacy, to prevent people in @Patricia situation from being identified. Nice observation from cis.upenn.edu/~aaroth/privacybook.html : "the Fundamental Law of Information Recovery states that overly accurate answers to too many questions will destroy privacy in a spectacular way." – Ben Voigt Mar 7 at 19:58
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@PatriciaShanahan if the surveys were released monthly and one month there was exactly one 50-54 female CS PhD student and the next month there was exactly one 55-59 female CS PhD student, then a careful observer could determine your birthday to the nearest month. There is a tremendous amount of leaked information. – emory Mar 7 at 21:32

The website will record your IP address. The Company's network assigns your IP address. Just associate the two ...

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I think the answer would be stronger with some more text. Perhaps saying that this is one possibility? – Neil Smithline Mar 8 at 4:07
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This only works if the application is internally based. If the survey is done using something like SurveyMonkey, the external IP address of the company will be used. If the application is internal and something like DHCP reservations is used this answer would work as you could trace the DHCP reservations to each computer and then the user who works with that computer. – Danny Klatt Mar 8 at 14:58
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Depends, some workplaces (universities especially) use public IPs everywhere. Some places force their traffic through proxies which can add x-forwarded-for headers which external sites can record. – Peter Green Mar 8 at 23:53

De-identification from surveys is a big issue in statistics, as what people think of as anonymous data usually isn't when aggregated.

Even if you have a completely secure way of anonymously inputing data, and someone can't access the logs of who entered what, the responses in the survey are often enough to identify you.

Consider this example survey:

  1. What is your gender? Male / Female
  2. What is your age bracket?
    • < 25
    • 25 - <35
    • 35 - <45
    • > 45
  3. What is your work area?
    • HR
    • Management
    • IT Support
    • Sales
  4. On a scale of 1-10 how much to you like working here? ____

Individually every question is quite useless, but using the first 3, at even a large company you can pretty easily figure out what everyone thinks of the organisation.

Consider: Bob (Male, 37 in HR) and Jane (Female, 37 in HR), using just our fields above we can already clearly de-identify their responses.

Additionally, since HR already has access to a list of gender, age and work area they could just cross-reference both datasets to directly get each individuals score. There is always a possibility of clashes, but as the number of identity like questions goes up, then the chances of collision decreases dramatically.

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An even more specific-to-user way is to create the surveys from a list. The list would include employee names, emails, id, etc. You can then send out a survey with a unique link to each email address for the employee and call it anonymous. While this is unethical (saying a survey is anonymous when it really isn't), I have seen it done in a few different instances and have also done it using PHP/JS.

An example would be your email receiving a link such as https://example.com/survey.php/id=bm90LWFub255bW91cy1zdXJ2ZXk=. The id variable can hold encoded information that is found in the list and unique to the employee. Companies also use this to gather information on what specific people say in said surveys.

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To add since it was mentioned the link was sent via mass-email: My last work-place would send out batched emails akin to this, but would forge extra "CC" headers. It would still send to every recipient, but with a different email per person (or whatever our email admin wanted). Thus looking like everyone got the same email link but in fact did not. (I probably am missing some details, our email admin was the wizard who did the work for this system.) – admalledd Mar 7 at 16:48
    
@admalledd Yes. When I read that the link was mass-emailed and had no identifier, I thought, "Not necessarily". Sure "example.com/survey/user=FredSmith" is a dead giveaway. But if you wanted to me subtle, you could send one person "example.com/marketingsurvey" and another "mktgsurvey" and another "marketing-survey" and another "marketing", etc. If there's a number or meaningless codes in there, "survey1329B", that MAY just identify which survey, but it may well identify the recipient. – Jay Mar 9 at 14:51

If you are concerned about your IP address you might want to fill in the survey in the Tor Browser. Of course, you might need to enable Javascript, which might give you out.

Additionally, since the survey is anonymous, you might even just want to ignore it if you feel like you the survey is not truly anonymous. Ideally, they would not be able to know you have not filled out the survey if the survey URLs are not unique, and no login is required.

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Ignoring the survey will get your name on the "didn't fill out the survey" list. – Bob Jarvis Mar 9 at 12:42
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@BobJarvis Yes, but only if they are able to isolate you from all the other employees taking the survey. Nonetheless, they will still not gather this data, unless they do a new survey or they confront you directly. If they do happen to confront you directly about not taking the survey, you'll know for sure they are not playing by the rules. – Frederik A. Mikkelsen Mar 9 at 13:35

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