Impact
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An attacker can read arbitrary `.md` files from the server's filesystem due to an [improper input validation](https://cwe.mitre.org/data/definitions/20.html), which results in the ability to perform a [relative path traversal](https://cwe.mitre.org/data/definitions/23.html).
CVSSv3 string: AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
PoC / Quicktest
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To verify if you are affected, you can try to open the following URL: `http://localhost:3000/..%2F..%2FREADME#` (replace `http://localhost:3000` with your instance's base-URL e.g. `https://demo.hedgedoc.org/..%2F..%2FREADME#`).
- If you see a README page being rendered, you run an affected version.
Analysis
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The attack works due the fact that [the internal router, passes the url-encoded alias](https://github.com/hedgedoc/hedgedoc/blob/master/lib/web/note/router.js#L26) to the `noteController.showNote`-function. This function passes the input directly to [`findNote()`](78a732abe6/lib/web/note/util.js (L10)) utility function, that will pass it on the the [`parseNoteId()`](78a732abe6/lib/models/note.js (L188-L258))-function, that tries to make sense out of the noteId/alias and check if a note already exists and if so, if a corresponding file on disk was updated.
If no note exists the [note creation-function is called](78a732abe6/lib/models/note.js (L240-L245)), which pass this unvalidated alias, with a `.md` appended, into a [`path.join()`-function](78a732abe6/lib/models/note.js (L99)) which is read from the filesystem in the follow up routine and provides the pre-filled content of the new note.
This allows an attacker to not only read arbitrary `.md` files from the filesystem, but also observes changes to them.
The usefulness of this attack can be considered limited, since mainly markdown files are use the file-ending `.md` and all markdown files contained in the hedgedoc project, like the README, are public anyway. If other protections such as a chroot or container or proper file permissions are in place, this attack's usefulness is rather limited.
Workarounds
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On a reverse-proxy level one can force a URL-decode, which will prevent this attack because the router will not accept such a path.
For more information
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If you have any questions or comments about this advisory:
* Open an topic on [our community forum](https://community.hedgedoc.org)
* Join our [matrix room](https://chat.hedgedoc.org)
Advisory link
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https://github.com/hedgedoc/hedgedoc/security/advisories/GHSA-p528-555r-pf87
Signed-off-by: Christoph (Sheogorath) Kern <sheogorath@shivering-isles.com>
Since the interface is not always in english, we mostly removed the lang attribute from all html tags. Since the error messages in error.ejs are not translated, but always in english, there the global lang="en" should be kept.
Also in the slide and editor template the div, which contains the user generated text, has the attribute translate="no" now, to avoid unwanted translations.
Since on the publish view (pretty.ejs) only the user generated content is shown, we set the lang to the language defined in yaml (or 'en') as a default, but that was also moved to the corresponding markdown div instead of html.
Fixes#881
See also #437
Signed-off-by: Philip Molares <philip.molares@udo.edu>
After https://github.com/hedgedoc/hedgedoc/pull/969 was merged,
a separate configuration file for the sequelize-cli is no longer
required.
Signed-off-by: David Mehren <git@herrmehren.de>
This commit removes the need for separate migrations with the sequelize-cli
by running them with umzug on application startup.
This is a port of #384
Co-authored-by: Sheogorath <sheogorath@shivering-isles.com>
Signed-off-by: David Mehren <git@herrmehren.de>
