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Unicode 202E vuln fix #382

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Unicode 202E vuln fix #382

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8039ed0
Unicode 202E vuln fix
Gilgahex Aug 2, 2022
eb5845e
Merge pull request #1 from gregjacobs/master
Aug 23, 2022
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3 changes: 3 additions & 0 deletions src/match/url-match.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -170,6 +170,9 @@ export class UrlMatch extends Match {
getAnchorHref() {
let url = this.getUrl();

//Strip malicious Unicode SNYK-AUTOLINKER-2438289
url.replace('\u202E', '');
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@bassammaged bassammaged Aug 10, 2022 •
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Also, I suggest Strip the most RTLO common format U+202E and %E2%80%AE beside \u202E

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it should also be replaced globally with /\u202E/g

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would that be immune to ReDoS?

https://en.wikipedia.org/wiki/ReDoS

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@gregjacobs gregjacobs Aug 17, 2022 •
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Hey, not sure how this would actually fix the issue because the code isn't re-assigning the replacement result back to url. The code would need to be:

url = url.replace(/\u202E/g, '');

Does your new test pass even without this new line of code?

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@xfournet xfournet Sep 6, 2022 •
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even after correction of the test (see remark in autolinker-url.spec.ts) the test is failing whatever the changes here:

  • with this line
  • with the update line according greg comment
  • without this line

in my observation the \u202e char is never reaching this method because of parseHtml


return url.replace(/&/g, '&'); // any &'s in the URL should be converted back to '&' if they were displayed as & in the source html
}

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9 changes: 8 additions & 1 deletion tests/autolinker-url.spec.ts
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Expand Up @@ -1203,8 +1203,15 @@ describe('Autolinker Url Matching -', () => {
);
});

describe('unicode exploits', () => {
it('should strip out Right-To-Left Override Unicode characters for security', () => {
var result = autolinker.link('https://legit.ok/files\u202E4pm.asia');
expect(result).toBe('<a href="https://legit.ok/files4pm.asia"></a>');
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the expected result should be '<a href="https://legit.ok/files4pm.asia">legit.ok/files4pm.asia</a>'

});
});

describe('combination example', () => {
it(`should automatically link all of the URLs of many different forms`, () => {
it('should automatically link all of the URLs of many different forms', () => {
let inputStr = `
Joe went to http://yahoo.com and http://localhost today along with http://localhost:8000.
He also had a path on localhost: http://localhost:8000/abc, and a query string: http://localhost:8000?abc
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