DSpace is vulnerable to XML External Entity injection during archive imports

• The most severe practical impact is a case where an attacker obtains DSpace administrator credentials and uses the Batch Import feature with a malicious SAF archive to expose sensitive local files readable by the Tomcat user, or secrets and access tokens from an authenticated service via request forgery.
• An attacker without administrative credentials might use some other tactic to convince an administrator to import a malicious SAF archive they have supplied.

The Import from External Sources feature has a narrower attack vector. While this feature is usable by any DSpace Submitter, the malicious payload must be provided by the external source (e.g. arXiv, Crossref, OpenAIRE, or Creative Commons). No known method exists for an attacker to inject XXE via content uploads. Instead, the service itself would need to be compromised in such a way that it would inject a malicious payload into its API response.

Patches

The fix is included in DSpace 7.6.4, 8.2 and 9.1. Please upgrade to one of these versions.

If you cannot upgrade immediately, it is possible to manually patch your DSpace backend. (No changes are necessary to the frontend.) A pull request exists which can be used to patch systems running DSpace 7.6.x, 8.x or 9.0. This pull request provides central methods to retrieve Java XML, SAX, JAXB XML document builders with safe default settings, including XXE protection.

• Pull request for 7.x: https://github.com/DSpace/DSpace/pull/11032 (Downloadable patch file)
• Pull request for 8.x: https://github.com/DSpace/DSpace/pull/11034 (Downloadable patch file)
• Pull request for 9.0: https://github.com/DSpace/DSpace/pull/11035 (Downloadable patch file)

Apply the patch to your DSpace

If at all possible, we recommend upgrading your DSpace site based on the upgrade instructions. However, if you are unable to do so, you can manually apply the above patches to your DSpace backend as follows:

1. Download the appropriate patch file to the machine where DSpace backend is running
2. From the [dspace-src] folder, apply the patch, e.g. git apply [name-of-file].patch
3. Now, update your DSpace site (based loosely on the Upgrade instructions). This generally involves three steps:
   1. Rebuild DSpace, e.g. mvn -U clean package (This will recompile all DSpace backend code)
   2. Redeploy DSpace, e.g. ant update (This will copy all newly built code to your installation directory). Depending on your setup you also may need to copy the updated "server" webapp over to your Tomcat webapps folder.
   3. Restart Tomcat (or runnable JAR)

Workarounds

Patching the system is the recommended fix. It is not possible to fully protect your system via workarounds.

That said, until you are able to patch your system or upgrade, you can apply these best practices:

• Administrators must carefully inspect any SAF archives (they did not construct themselves) before importing. If SAF archives are too large to manually inspect, you should avoid importing them until your site is patched.
• As necessary, affected external services can be disabled (see documentation) to mitigate the ability for a malicious payload to be delivered via external service APIs.

Credits

Discovered & reported by Pablo Picurelli Ortiz (@superpegaso2703) Code fix developed by Kim Shepherd (@kshepherd) of The Library Code

For more information

• XXE Cheat Sheet / Explanations
• If you have any questions or comments about this advisory, please contact us at [email protected]