Impact
---
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
---
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
---
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
---
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
---
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
---
https://github.com/hedgedoc/hedgedoc/security/advisories/GHSA-p528-555r-pf87
Signed-off-by: Christoph (Sheogorath) Kern <sheogorath@shivering-isles.com>
This reuses the `realtime.getStatus` method to get the state of the
application state on every prometheus scrape cycle.
Signed-off-by: David Mehren <git@herrmehren.de>
The previous error message stated that the version of Node or
Yarn is "outdated", which might be accurate coincidentally,
but is not what the script checks.
This commit changes the wording to use "not supported", which
is more accurate to the true check in the script.
Signed-off-by: David Mehren <git@herrmehren.de>
As Node 10 will be EOL at April 30th, we should stop supporting
and/or promoting the usage of that version.
See also https://endoflife.date/nodejs
Signed-off-by: David Mehren <git@herrmehren.de>
This reverts the documentation changes of bf0a7ebee7. This is necessary as the omitted remarks about `.sequlizerc` can't be omitted until 1.8 is released.
Signed-off-by: Philip Molares <philip.molares@udo.edu>
This dependency is outdated anyway (it still uses the old imgur api) and for our purposes we can substitute it with a simple POST request via note-fetch.
Signed-off-by: Philip Molares <philip.molares@udo.edu>
The dark theme is mostly built on top of the mkdocs slate theme.
Signed-off-by: Philip Molares <philip.molares@udo.edu>
Co-Authored-by: Tilman Vatteroth <git@tilmanvatteroth.de>
To make it easier to get started, this commit adds a minimal
`config.json` snipped to the manual setup instruction.
Signed-off-by: David Mehren <git@herrmehren.de>
Build instructions are not relevant for most users.
Contact info can already be found on the 'Home' page.
Signed-off-by: David Mehren <git@herrmehren.de>
Directing users to use the container repo to install
HedgeDoc has caused upgrade-trouble in the past, after we made
incompatible changes to the docker-compose.yml in the repo.
This commit inserts a minimal docker-compose snipped in the
docs, which can be used to get started. Upgrading can then
be performed by just incrementing the referenced image version.
Signed-off-by: David Mehren <git@herrmehren.de>
