How badly should I try to prevent a user from XSSing themselves?
Let's say a user can store some data in a web app. I'm now only talking about that sort of data the user can THEMSELVES view, not that is intended to be viewed by other users of the webapp. (Or if other users may view this data then it is handled to them in a more secure way.)
How horrible would it be to allow some XSS vulnerability in this data?
Of course, a purist's answer would clearly be: "No vulnerabilities are allowed". But honestly - why?
Everything that is allowed is the user XSSing THEMSELVES. What's the harm here? Other users are protected. And I can't see a reason why would someone mount an attack against themselves (except if it is a harmless one, in which case - again - no harm is done).
My gut feelings are that the above reasoning will raise some eyebrows... OK, then what am I failing to see?
xss attacks
asked 9 hours ago
gaazkamgaazkam
1,3312819
add a comment |
Let's say a user can store some data in a web app. I'm now only talking about that sort of data the user can THEMSELVES view, not that is intended to be viewed by other users of the webapp. (Or if other users may view this data then it is handled to them in a more secure way.)
How horrible would it be to allow some XSS vulnerability in this data?
Of course, a purist's answer would clearly be: "No vulnerabilities are allowed". But honestly - why?
Everything that is allowed is the user XSSing THEMSELVES. What's the harm here? Other users are protected. And I can't see a reason why would someone mount an attack against themselves (except if it is a harmless one, in which case - again - no harm is done).
My gut feelings are that the above reasoning will raise some eyebrows... OK, then what am I failing to see?
xss attacks
asked 9 hours ago
gaazkamgaazkam
1,3312819
How can you limit the scope of an XSS vuln to just some data? This is asking to open the door to everything getting compromised. Don't be lazy with it
– Crumblez
9 hours ago
add a comment |
Let's say a user can store some data in a web app. I'm now only talking about that sort of data the user can THEMSELVES view, not that is intended to be viewed by other users of the webapp. (Or if other users may view this data then it is handled to them in a more secure way.)
How horrible would it be to allow some XSS vulnerability in this data?
Of course, a purist's answer would clearly be: "No vulnerabilities are allowed". But honestly - why?
Everything that is allowed is the user XSSing THEMSELVES. What's the harm here? Other users are protected. And I can't see a reason why would someone mount an attack against themselves (except if it is a harmless one, in which case - again - no harm is done).
My gut feelings are that the above reasoning will raise some eyebrows... OK, then what am I failing to see?
xss attacks
asked 9 hours ago
gaazkamgaazkam
1,3312819
Let's say a user can store some data in a web app. I'm now only talking about that sort of data the user can THEMSELVES view, not that is intended to be viewed by other users of the webapp. (Or if other users may view this data then it is handled to them in a more secure way.)
How horrible would it be to allow some XSS vulnerability in this data?
Of course, a purist's answer would clearly be: "No vulnerabilities are allowed". But honestly - why?
Everything that is allowed is the user XSSing THEMSELVES. What's the harm here? Other users are protected. And I can't see a reason why would someone mount an attack against themselves (except if it is a harmless one, in which case - again - no harm is done).
My gut feelings are that the above reasoning will raise some eyebrows... OK, then what am I failing to see?
xss attacks
xss attacks
asked 9 hours ago
gaazkamgaazkam
1,3312819
asked 9 hours ago
gaazkamgaazkam
1,3312819
asked 9 hours ago
gaazkamgaazkam
1,3312819
asked 9 hours ago
gaazkamgaazkam
1,3312819
asked 9 hours ago
gaazkamgaazkam
1,3312819
1,3312819
How can you limit the scope of an XSS vuln to just some data? This is asking to open the door to everything getting compromised. Don't be lazy with it
– Crumblez
9 hours ago
add a comment |
How can you limit the scope of an XSS vuln to just some data? This is asking to open the door to everything getting compromised. Don't be lazy with it
– Crumblez
9 hours ago
How can you limit the scope of an XSS vuln to just some data? This is asking to open the door to everything getting compromised. Don't be lazy with it
– Crumblez
9 hours ago
How can you limit the scope of an XSS vuln to just some data? This is asking to open the door to everything getting compromised. Don't be lazy with it
– Crumblez
9 hours ago
add a comment |
2 Answers
2
active
oldest
votes
This is actually a real concept, "Self XSS" which is sufficiently common that if you open https://facebook.com and then open the developer tools, they warn you about it 
Obviously Facebook is a specific type of target and whether this issue matters to you or not, would depend on the exact nature of your site, but you may not be able to discount the idea of one user using social engineering techniques to get another user to attack themselves.
answered 9 hours ago
Rоry McCuneRоry McCune
52.8k13113188
add a comment |
Although you are right in that it might not matter so much from an attack point of view. From a usability point of view, the user might come across some 'unexpected behavior'. A while ago I used to have to work with software that had an obvious SQL injection problem (contractors couldn't/wouldn't fix it). This meant that unexpecting users would enter in something seemingly harmless such as their name "O'Brien", which would trigger an SQL injection and for computer illiterate people it was unexpected behavior. It is probably less likely with XSS, however consider the following if a user uses <> instead of () the data might seem to disappear. A proof of concept is below:
<html>
<head><title>HI</title></head>
<body>
<h1>WEBSITE</h1>
Hey my name is <travis>.
</body>
</html>
Note that when this website is rendered, the word 'travis', is not rendered.
answered 8 hours ago
meowcatmeowcat
1634
add a comment |
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2 Answers
2
active
oldest
votes
2 Answers
2
active
oldest
votes
active
oldest
votes
active
oldest
votes
This is actually a real concept, "Self XSS" which is sufficiently common that if you open https://facebook.com and then open the developer tools, they warn you about it
Obviously Facebook is a specific type of target and whether this issue matters to you or not, would depend on the exact nature of your site, but you may not be able to discount the idea of one user using social engineering techniques to get another user to attack themselves.
answered 9 hours ago
Rоry McCuneRоry McCune
52.8k13113188
add a comment |
This is actually a real concept, "Self XSS" which is sufficiently common that if you open https://facebook.com and then open the developer tools, they warn you about it
Obviously Facebook is a specific type of target and whether this issue matters to you or not, would depend on the exact nature of your site, but you may not be able to discount the idea of one user using social engineering techniques to get another user to attack themselves.
answered 9 hours ago
Rоry McCuneRоry McCune
52.8k13113188
add a comment |
This is actually a real concept, "Self XSS" which is sufficiently common that if you open https://facebook.com and then open the developer tools, they warn you about it
Obviously Facebook is a specific type of target and whether this issue matters to you or not, would depend on the exact nature of your site, but you may not be able to discount the idea of one user using social engineering techniques to get another user to attack themselves.
answered 9 hours ago
Rоry McCuneRоry McCune
52.8k13113188
This is actually a real concept, "Self XSS" which is sufficiently common that if you open https://facebook.com and then open the developer tools, they warn you about it
Obviously Facebook is a specific type of target and whether this issue matters to you or not, would depend on the exact nature of your site, but you may not be able to discount the idea of one user using social engineering techniques to get another user to attack themselves.
answered 9 hours ago
Rоry McCuneRоry McCune
52.8k13113188
answered 9 hours ago
Rоry McCuneRоry McCune
52.8k13113188
answered 9 hours ago
Rоry McCuneRоry McCune
52.8k13113188
answered 9 hours ago
Rоry McCuneRоry McCune
52.8k13113188
52.8k13113188
add a comment |
add a comment |
Although you are right in that it might not matter so much from an attack point of view. From a usability point of view, the user might come across some 'unexpected behavior'. A while ago I used to have to work with software that had an obvious SQL injection problem (contractors couldn't/wouldn't fix it). This meant that unexpecting users would enter in something seemingly harmless such as their name "O'Brien", which would trigger an SQL injection and for computer illiterate people it was unexpected behavior. It is probably less likely with XSS, however consider the following if a user uses <> instead of () the data might seem to disappear. A proof of concept is below:
<html>
<head><title>HI</title></head>
<body>
<h1>WEBSITE</h1>
Hey my name is <travis>.
</body>
</html>
Note that when this website is rendered, the word 'travis', is not rendered.
answered 8 hours ago
meowcatmeowcat
1634
add a comment |
Although you are right in that it might not matter so much from an attack point of view. From a usability point of view, the user might come across some 'unexpected behavior'. A while ago I used to have to work with software that had an obvious SQL injection problem (contractors couldn't/wouldn't fix it). This meant that unexpecting users would enter in something seemingly harmless such as their name "O'Brien", which would trigger an SQL injection and for computer illiterate people it was unexpected behavior. It is probably less likely with XSS, however consider the following if a user uses <> instead of () the data might seem to disappear. A proof of concept is below:
<html>
<head><title>HI</title></head>
<body>
<h1>WEBSITE</h1>
Hey my name is <travis>.
</body>
</html>
Note that when this website is rendered, the word 'travis', is not rendered.
answered 8 hours ago
meowcatmeowcat
1634
add a comment |
Although you are right in that it might not matter so much from an attack point of view. From a usability point of view, the user might come across some 'unexpected behavior'. A while ago I used to have to work with software that had an obvious SQL injection problem (contractors couldn't/wouldn't fix it). This meant that unexpecting users would enter in something seemingly harmless such as their name "O'Brien", which would trigger an SQL injection and for computer illiterate people it was unexpected behavior. It is probably less likely with XSS, however consider the following if a user uses <> instead of () the data might seem to disappear. A proof of concept is below:
<html>
<head><title>HI</title></head>
<body>
<h1>WEBSITE</h1>
Hey my name is <travis>.
</body>
</html>
Note that when this website is rendered, the word 'travis', is not rendered.
answered 8 hours ago
meowcatmeowcat
1634
Although you are right in that it might not matter so much from an attack point of view. From a usability point of view, the user might come across some 'unexpected behavior'. A while ago I used to have to work with software that had an obvious SQL injection problem (contractors couldn't/wouldn't fix it). This meant that unexpecting users would enter in something seemingly harmless such as their name "O'Brien", which would trigger an SQL injection and for computer illiterate people it was unexpected behavior. It is probably less likely with XSS, however consider the following if a user uses <> instead of () the data might seem to disappear. A proof of concept is below:
<html>
<head><title>HI</title></head>
<body>
<h1>WEBSITE</h1>
Hey my name is <travis>.
</body>
</html>
Note that when this website is rendered, the word 'travis', is not rendered.
answered 8 hours ago
meowcatmeowcat
1634
answered 8 hours ago
meowcatmeowcat
1634
answered 8 hours ago
meowcatmeowcat
1634
answered 8 hours ago
meowcatmeowcat
1634
1634
add a comment |
add a comment |
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How can you limit the scope of an XSS vuln to just some data? This is asking to open the door to everything getting compromised. Don't be lazy with it
– Crumblez
9 hours ago