Directory Traversal Affecting ait-core package, versions [,2.6.1)[3.1.0,3.1.1)

ait-core is a NASA JPL's Ground Data System toolkit for Instrument and CubeSat Missions

Affected versions of this package are vulnerable to Directory Traversal in the StreamCaptureManagerServer process when handling unauthenticated HTTP POST requests to the /NAME/start endpoint. An attacker can append arbitrary data to files outside the intended log directory by supplying crafted values for log_dir_path, path, or file_name_pattern fields, resulting in the creation or modification of files anywhere on the filesystem that the process has write access to. This can lead to data corruption, denial of service, or potentially remote code execution if executable files are modified and subsequently run by a user. The attack can be performed remotely over the network without authentication, either directly or via a browser on the same network sending crafted requests.

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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