DSpace Cross Site Scripting (XSS) via a deposited HTML/XML document
ImpactIn DSpace 7.0 through 7.6.1, when an HTML, XML or JavaScript Bitstream is downloaded, the user's browser _may_ execute any embedded JavaScript.  If that embedded JavaScript is malicious, there is a risk of an XSS attack.This attack may only be initialized by a user who already has Submitter privileges in the repository. The submitter must upload the malicious HTML/XML/JavaScript file themselves. The attack itself would not occur until a visitor or logged-in user downloads the file or clicks on a download link shared by the attacker.If your site is running the frontend and backend from separate domains, CORS and CSRF protection built into DSpace help to limit the impact of the attack.If the repository is configured to only download HTML / XML / JavaScript Bitstreams using the [`Content-Disposition: attachment`](https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Content-Disposition) header, then the attack is no longer possible.  See "Workarounds" below.PatchesThe fix is included in both 8.0 and 7.6.2.  Please upgrade to one of these versions, or manually apply one of the "Workarounds" below.If you are already running 7.6 or 7.6.1, then this vulnerability can be fixed via a configuration update in your `dspace.cfg` configuration file.  See details in below.Workarounds**DSpace sites running 7.6 or 7.6.1** can fix this issue by adding the following `webui.content_disposition_format` settings to their `dspace.cfg` (or `local.cfg`).  These settings force all HTML, XML, RDF & JavaScript files to always be downloaded to a user's machine, blocking the attack.  For more details see [PR #9638](https://github.com/DSpace/DSpace/pull/9638)These settings will take effect immediately. There is no need to restart Tomcat.To verify the settings are working: upload an HTML or XML file to an in-progress submission. Attempt to download the file. The file should *not* open in your browser window. Instead, it should download to your local computer.**DSpace sites running 7.0 through 7.5** will need to **either** (CHOOSE ONE):Upgrade to 7.6.2 or 8.0Or, upgrade to 7.6 or 7.6.1 and then apply the configuration change mentioned aboveOr, manually add the `webui.content_disposition_format` setting (which was first released in 7.6), and then apply the configuration changes mentioned above.The `webui.content_disposition_format` setting can be added by applying the changes in [PR #8891](https://github.com/DSpace/DSpace/pull/8891).  A [`patch` file](https://github.com/DSpace/DSpace/pull/8891.patch) is also available.Please be aware this patch may not apply cleanly to all prior versions of 7.x. In that scenario, you would need to find a way to manually apply the changes or consider a different workaround.Or, find a way in your Apache or NGinx proxy to force the `Content-Disposition: attachment` header to be sent for **all files** downloaded via `/server/api/core/bitstreams/[uuid]/content` in the REST API.NOTE: This workaround will patch the vulnerability. However, it does so by no longer allowing users to open _any_ downloaded files in their browser window. (This behavior may or may not be desirable in the long term, so you may wish to remove it in the future, once you have upgraded.)For example, in Apache, using "mod_headers", you may add a configuration similar to this in your `<VirtualHost>`:ReferencesDiscovered and reported by Muhammad Zeeshan ([Xib3rR4dAr](https://github.com/Xib3rR4dAr))For more informationIf you have any questions or comments about this advisory:Email us at [security@dspace.org](mailto:security@dspace.org)