Browser cross-site scripting filter disabled
Summary: PortSwigger Research describes applications that set the response header X-XSS-Protection: 0, which tells browsers with built-in cross-site scripting filters, including Internet Explorer, to turn those filters off. The text notes this is not a vulnerability by itself, since XSS filters can sometimes be used to attack application users, but that the header's presence should be reviewed for its effect on the application's security posture.
What's compelling: The recommended alternative, X-XSS-Protection: 1; mode=block, makes a browser render a blank page on detecting an XSS attack instead of trying to sanitize the injected script, which the text says is considerably less likely to introduce new security issues. Any application still sending X-XSS-Protection: 0 has given up that basic layer of protection for its users.
Read the original at PortSwigger Research ↗
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