Directory Traversal Affecting pyload-ng package, versions [,0.5.0b3.dev75)


Severity

Recommended
0.0
high
0
10

CVSS assessment made by Snyk's Security Team. Learn more

Threat Intelligence

Exploit Maturity
Proof of concept
EPSS
0.05% (24th percentile)

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  • Snyk IDSNYK-PYTHON-PYLOADNG-6071706
  • published22 Nov 2023
  • disclosed21 Nov 2023
  • creditvergl4s

Introduced: 21 Nov 2023

CVE-2023-47890  (opens in a new tab)
CWE-22  (opens in a new tab)

How to fix?

Upgrade pyload-ng to version 0.5.0b3.dev75 or higher.

Overview

pyload-ng is a The free and open-source Download Manager written in pure Python

Affected versions of this package are vulnerable to Directory Traversal when the add_package and edit_package functions are used. An attacker can store files anywhere on the server and gain command execution by abusing scripts. This is only exploitable if a user creates a new package and then edits it to pick any arbitrary directory in the filesystem.

Details

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

References

CVSS Scores

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