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Why isn't this XSS working?
The Next CEO of Stack OverflowPHP: if charset mismatches (htmlentities UTF-8) viewed by client as ISO-8859-1 (or vice versa)How is this XSS attack working?Why doesn't this XSS attack work?XSS - Bypass this RegExpWhy do ID attributes need stricter validation?XSS via JSON: Why does a web application not sanitize either its incoming params hash or its outgoing JSON values of malicious tags like Script?Why isn't this code running?Why does this XSS challenge require %0A to work?BeEF XSS - internal workingWhy this XSS payload doesn't work?
I'm learning DOM XSS and I have this code :
<html>
<body>
Select your language:
<select>
<script>
document.write("<OPTION value=1>"+document.location.href.substring(document.location.href.indexOf("default=")+8)+"</OPTION>");
document.write("<OPTION value=2>English</OPTION>");
</script>
</select>
</body>
</html>
but I don't understand why this payload doesn't trigger any XSS :
t.html?default=test</option><img src=x onerror=alert(1)/>
It looks like the symbols are encoded and I don't understand why...
I took the script from https://www.owasp.org/index.php/DOM_Based_XSS so I guess it's vulnerable but I don't know how to exploit it...
xss
edited Mar 25 at 10:07
Alex Probert
3641216
asked Mar 25 at 5:06
NeolexNeolex
10219
add a comment |
I'm learning DOM XSS and I have this code :
<html>
<body>
Select your language:
<select>
<script>
document.write("<OPTION value=1>"+document.location.href.substring(document.location.href.indexOf("default=")+8)+"</OPTION>");
document.write("<OPTION value=2>English</OPTION>");
</script>
</select>
</body>
</html>
but I don't understand why this payload doesn't trigger any XSS :
t.html?default=test</option><img src=x onerror=alert(1)/>
It looks like the symbols are encoded and I don't understand why...
I took the script from https://www.owasp.org/index.php/DOM_Based_XSS so I guess it's vulnerable but I don't know how to exploit it...
xss
edited Mar 25 at 10:07
Alex Probert
3641216
asked Mar 25 at 5:06
NeolexNeolex
10219
add a comment |
I'm learning DOM XSS and I have this code :
<html>
<body>
Select your language:
<select>
<script>
document.write("<OPTION value=1>"+document.location.href.substring(document.location.href.indexOf("default=")+8)+"</OPTION>");
document.write("<OPTION value=2>English</OPTION>");
</script>
</select>
</body>
</html>
but I don't understand why this payload doesn't trigger any XSS :
t.html?default=test</option><img src=x onerror=alert(1)/>
It looks like the symbols are encoded and I don't understand why...
I took the script from https://www.owasp.org/index.php/DOM_Based_XSS so I guess it's vulnerable but I don't know how to exploit it...
xss
edited Mar 25 at 10:07
Alex Probert
3641216
asked Mar 25 at 5:06
NeolexNeolex
10219
I'm learning DOM XSS and I have this code :
<html>
<body>
Select your language:
<select>
<script>
document.write("<OPTION value=1>"+document.location.href.substring(document.location.href.indexOf("default=")+8)+"</OPTION>");
document.write("<OPTION value=2>English</OPTION>");
</script>
</select>
</body>
</html>
but I don't understand why this payload doesn't trigger any XSS :
t.html?default=test</option><img src=x onerror=alert(1)/>
It looks like the symbols are encoded and I don't understand why...
I took the script from https://www.owasp.org/index.php/DOM_Based_XSS so I guess it's vulnerable but I don't know how to exploit it...
xss
xss
edited Mar 25 at 10:07
Alex Probert
3641216
asked Mar 25 at 5:06
NeolexNeolex
10219
edited Mar 25 at 10:07
Alex Probert
3641216
asked Mar 25 at 5:06
NeolexNeolex
10219
edited Mar 25 at 10:07
Alex Probert
3641216
edited Mar 25 at 10:07
Alex Probert
3641216
edited Mar 25 at 10:07
Alex Probert
3641216
3641216
asked Mar 25 at 5:06
NeolexNeolex
10219
asked Mar 25 at 5:06
NeolexNeolex
10219
asked Mar 25 at 5:06
NeolexNeolex
10219
10219
add a comment |
add a comment |
1 Answer
1
active
oldest
votes
It doesn't work because the payload is URL-encoded.
If you navigate to
https://example.com/?foo=<>"
you will see the literal characters <>" in your URL bar, but the browser has actually requested
https://example.com/?foo=%3C%3E%22
. That is, your browser always URL-encodes some characters in the query string, including quotes and angle brackets.
So, if you access location.href via JS, the payload in your example will be returned as
test%3C/option%3E%3Cimg%20src=x%20onerror=alert(1)/%3E
. This does not produce any HTML tags unless you URL-decode it first.
Note: As far as I know, all modern browsers now behave that way, but historically, some implementations have implicitly URL-decoded values for the location interface. In these browsers, your attack would have worked.
answered Mar 25 at 5:47
ArminiusArminius
37.9k13123120
Oh I see... Ok ! Thank you so much ! So this webpage is not vulnerable anymore ?
– Neolex
Mar 25 at 5:53
2
There may still be browsers that let you sneak literal quotes and angle brackets somewhere in the URL where they don't get URL-encoded. But I believe your example isn't vulnerable in modern Chrome and Firefox.
– Arminius
Mar 25 at 5:58
Ok ! Thanks a lot !
– Neolex
Mar 25 at 6:05
add a comment |
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1 Answer
1
active
oldest
votes
1 Answer
1
active
oldest
votes
active
oldest
votes
active
oldest
votes
It doesn't work because the payload is URL-encoded.
If you navigate to
https://example.com/?foo=<>"
you will see the literal characters <>" in your URL bar, but the browser has actually requested
https://example.com/?foo=%3C%3E%22
. That is, your browser always URL-encodes some characters in the query string, including quotes and angle brackets.
So, if you access location.href via JS, the payload in your example will be returned as
test%3C/option%3E%3Cimg%20src=x%20onerror=alert(1)/%3E
. This does not produce any HTML tags unless you URL-decode it first.
Note: As far as I know, all modern browsers now behave that way, but historically, some implementations have implicitly URL-decoded values for the location interface. In these browsers, your attack would have worked.
answered Mar 25 at 5:47
ArminiusArminius
37.9k13123120
Oh I see... Ok ! Thank you so much ! So this webpage is not vulnerable anymore ?
– Neolex
Mar 25 at 5:53
2
There may still be browsers that let you sneak literal quotes and angle brackets somewhere in the URL where they don't get URL-encoded. But I believe your example isn't vulnerable in modern Chrome and Firefox.
– Arminius
Mar 25 at 5:58
Ok ! Thanks a lot !
– Neolex
Mar 25 at 6:05
add a comment |
It doesn't work because the payload is URL-encoded.
If you navigate to
https://example.com/?foo=<>"
you will see the literal characters <>" in your URL bar, but the browser has actually requested
https://example.com/?foo=%3C%3E%22
. That is, your browser always URL-encodes some characters in the query string, including quotes and angle brackets.
So, if you access location.href via JS, the payload in your example will be returned as
test%3C/option%3E%3Cimg%20src=x%20onerror=alert(1)/%3E
. This does not produce any HTML tags unless you URL-decode it first.
Note: As far as I know, all modern browsers now behave that way, but historically, some implementations have implicitly URL-decoded values for the location interface. In these browsers, your attack would have worked.
answered Mar 25 at 5:47
ArminiusArminius
37.9k13123120
Oh I see... Ok ! Thank you so much ! So this webpage is not vulnerable anymore ?
– Neolex
Mar 25 at 5:53
2
There may still be browsers that let you sneak literal quotes and angle brackets somewhere in the URL where they don't get URL-encoded. But I believe your example isn't vulnerable in modern Chrome and Firefox.
– Arminius
Mar 25 at 5:58
Ok ! Thanks a lot !
– Neolex
Mar 25 at 6:05
add a comment |
It doesn't work because the payload is URL-encoded.
If you navigate to
https://example.com/?foo=<>"
you will see the literal characters <>" in your URL bar, but the browser has actually requested
https://example.com/?foo=%3C%3E%22
. That is, your browser always URL-encodes some characters in the query string, including quotes and angle brackets.
So, if you access location.href via JS, the payload in your example will be returned as
test%3C/option%3E%3Cimg%20src=x%20onerror=alert(1)/%3E
. This does not produce any HTML tags unless you URL-decode it first.
Note: As far as I know, all modern browsers now behave that way, but historically, some implementations have implicitly URL-decoded values for the location interface. In these browsers, your attack would have worked.
answered Mar 25 at 5:47
ArminiusArminius
37.9k13123120
It doesn't work because the payload is URL-encoded.
If you navigate to
https://example.com/?foo=<>"
you will see the literal characters <>" in your URL bar, but the browser has actually requested
https://example.com/?foo=%3C%3E%22
. That is, your browser always URL-encodes some characters in the query string, including quotes and angle brackets.
So, if you access location.href via JS, the payload in your example will be returned as
test%3C/option%3E%3Cimg%20src=x%20onerror=alert(1)/%3E
. This does not produce any HTML tags unless you URL-decode it first.
Note: As far as I know, all modern browsers now behave that way, but historically, some implementations have implicitly URL-decoded values for the location interface. In these browsers, your attack would have worked.
answered Mar 25 at 5:47
ArminiusArminius
37.9k13123120
edited Mar 25 at 5:53
answered Mar 25 at 5:47
ArminiusArminius
37.9k13123120
answered Mar 25 at 5:47
ArminiusArminius
37.9k13123120
answered Mar 25 at 5:47
ArminiusArminius
37.9k13123120
37.9k13123120
Oh I see... Ok ! Thank you so much ! So this webpage is not vulnerable anymore ?
– Neolex
Mar 25 at 5:53
2
There may still be browsers that let you sneak literal quotes and angle brackets somewhere in the URL where they don't get URL-encoded. But I believe your example isn't vulnerable in modern Chrome and Firefox.
– Arminius
Mar 25 at 5:58
Ok ! Thanks a lot !
– Neolex
Mar 25 at 6:05
add a comment |
Oh I see... Ok ! Thank you so much ! So this webpage is not vulnerable anymore ?
– Neolex
Mar 25 at 5:53
2
There may still be browsers that let you sneak literal quotes and angle brackets somewhere in the URL where they don't get URL-encoded. But I believe your example isn't vulnerable in modern Chrome and Firefox.
– Arminius
Mar 25 at 5:58
Ok ! Thanks a lot !
– Neolex
Mar 25 at 6:05
Oh I see... Ok ! Thank you so much ! So this webpage is not vulnerable anymore ?
– Neolex
Mar 25 at 5:53
Oh I see... Ok ! Thank you so much ! So this webpage is not vulnerable anymore ?
– Neolex
Mar 25 at 5:53
2
2
There may still be browsers that let you sneak literal quotes and angle brackets somewhere in the URL where they don't get URL-encoded. But I believe your example isn't vulnerable in modern Chrome and Firefox.
– Arminius
Mar 25 at 5:58
There may still be browsers that let you sneak literal quotes and angle brackets somewhere in the URL where they don't get URL-encoded. But I believe your example isn't vulnerable in modern Chrome and Firefox.
– Arminius
Mar 25 at 5:58
Ok ! Thanks a lot !
– Neolex
Mar 25 at 6:05
Ok ! Thanks a lot !
– Neolex
Mar 25 at 6:05
add a comment |
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