Directory Traversal Affecting org.dspace:dspace-api package, versions [,7.6.7)[8.0-rc1,8.4)[9.0-rc1,9.3)[10-rc1,10.0)

org.dspace:dspace-api is a DSpace core data model and service APIs.

Affected versions of this package are vulnerable to Directory Traversal through the initCurator reporter output handling in dspace-api/src/main/java/org/dspace/curate/Curation.java. An attacker can overwrite or create files in arbitrary writable locations by supplying a crafted -r reporter path when running a curation task through the web UI. The vulnerable code passed this.reporter directly to new PrintStream(...) without restricting it to a configured base directory, so a DSpace collection, community, or site administrator could direct curation output into unexpected paths such as configuration files or webapp resources. This can break the site or, in chained scenarios, support privilege escalation by placing attacker-controlled content where the server later reads or executes it.

Workarounds

• Temporarily disable all Curation Tasks by commenting out every plugin.named.org.dspace.curate.CurationTask entry in dspace/config/modules/curate.cfg; this prevents the web UI and dspace curate from accepting the -r reporter output path and blocks the traversal/write attack path.
• If you rely on scheduled dspace curate jobs, stop or rework those cron jobs before disabling the curation task plugins; this avoids breaking legitimate automated curation runs while you remove the vulnerable feature.

A Directory Traversal attack (also known as path traversal) aims to access files and directories that are stored outside the intended folder. By manipulating files with "dot-dot-slash (../)" sequences and its variations, or by using absolute file paths, it may be possible to access arbitrary files and directories stored on file system, including application source code, configuration, and other critical system files.

Directory Traversal vulnerabilities can be generally divided into two types:

• Information Disclosure: Allows the attacker to gain information about the folder structure or read the contents of sensitive files on the system.

st is a module for serving static files on web pages, and contains a vulnerability of this type. In our example, we will serve files from the public route.

If an attacker requests the following URL from our server, it will in turn leak the sensitive private key of the root user.

curl http://localhost:8080/public/%2e%2e/%2e%2e/%2e%2e/%2e%2e/%2e%2e/root/.ssh/id_rsa

Note %2e is the URL encoded version of . (dot).

• Writing arbitrary files: Allows the attacker to create or replace existing files. This type of vulnerability is also known as Zip-Slip.

One way to achieve this is by using a malicious zip archive that holds path traversal filenames. When each filename in the zip archive gets concatenated to the target extraction folder, without validation, the final path ends up outside of the target folder. If an executable or a configuration file is overwritten with a file containing malicious code, the problem can turn into an arbitrary code execution issue quite easily.

The following is an example of a zip archive with one benign file and one malicious file. Extracting the malicious file will result in traversing out of the target folder, ending up in /root/.ssh/ overwriting the authorized_keys file:

2018-04-15 22:04:29 .....           19           19  good.txt
2018-04-15 22:04:42 .....           20           20  ../../../../../../root/.ssh/authorized_keys

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