Directory Traversal Affecting openmage/magento-lts package, versions <20.17.0

openmage/magento-lts is a This repository is the home of an unofficial community-driven project.

Affected versions of this package are vulnerable to Directory Traversal through the files request parameter in the dataflow import parsers. An attacker with administrative privileges can read or overwrite arbitrary files by supplying a crafted files value in an import request. The parsers build the import path directly from user input under the temp import directory and only strip a narrow ../ pattern, which leaves alternate traversal encodings and dot-slash variants usable to escape the intended import path. This can let a remote attacker manipulate files on the server and disrupt or compromise import processing.

Workarounds

• Restrict Dataflow access to trusted administrators only, so only authenticated admins can reach the vulnerable import paths and trigger file reads.
• Disable the Dataflow module entirely if you do not use it, which removes the attack surface for the files parameter path traversal.
• Block requests containing path traversal patterns at your web application firewall, preventing crafted files values such as ..././ or ....// from reaching the import parsers.

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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