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Sanitise XSS #10586

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merged 1 commit into from
Nov 21, 2022
Merged

Sanitise XSS #10586

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4 changes: 2 additions & 2 deletions src/Forms/HTMLEditor/HTMLEditorSanitiser.php
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Original file line number Diff line number Diff line change
Expand Up @@ -347,9 +347,9 @@ public function sanitise(HTMLValue $html)
}

// Matches "javascript:" with any arbitrary linebreaks inbetween the characters.
$regex = '/^\s*' . implode('\v*', str_split('javascript:')) . '/i';
$regex = '/^\s*' . implode('\s*', str_split('javascript:')) . '/i';
// Strip out javascript execution in href or src attributes.
foreach (['src', 'href'] as $dangerAttribute) {
foreach (['src', 'href', 'data'] as $dangerAttribute) {
if ($el->hasAttribute($dangerAttribute)) {
if (preg_match($regex, $el->getAttribute($dangerAttribute))) {
$el->removeAttribute($dangerAttribute);
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24 changes: 24 additions & 0 deletions tests/php/Forms/HTMLEditor/HTMLEditorSanitiserTest.php
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Original file line number Diff line number Diff line change
Expand Up @@ -104,6 +104,30 @@ public function testSanitisation()
'<iframe></iframe>',
'Mixed case javascript in the src attribute of an iframe is completely removed'
],
[
'iframe[src]',
"<iframe src=\"java\tscript:alert(0);\"></iframe>",
'<iframe></iframe>',
'Javascript with tab elements the src attribute of an iframe is completely removed'
],
[
'object[data]',
'<object data="OK"></object>',
'<object data="OK"></object>',
'Object with OK content in the data attribute is retained'
],
[
'object[data]',
'<object data=javascript:alert()>',
'<object></object>',
'Object with dangerous content in data attribute is completely removed'
],
[
'img[src]',
'<img src="https://owasp.org/myimage.jpg" style="url:xss" onerror="alert(1)">',
'<img src="https://owasp.org/myimage.jpg">',
'XSS vulnerable attributes starting with on or style are removed via configuration'
],
];

$config = HTMLEditorConfig::get('htmleditorsanitisertest');
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