https://github.com/bayotop/off-by-slash

Burp extension to detect alias traversal via NGINX misconfiguration at scale.
https://github.com/bayotop/off-by-slash

burpsuite nginx path-traversal

Last synced: 24 days ago
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Burp extension to detect alias traversal via NGINX misconfiguration at scale.

• Host: GitHub
• URL: https://github.com/bayotop/off-by-slash
• Owner: bayotop
• License: mit
• Created: 2018-10-20T19:37:25.000Z (about 6 years ago)
• Default Branch: master
• Last Pushed: 2021-11-18T15:08:36.000Z (about 3 years ago)
• Last Synced: 2024-11-09T18:25:12.948Z (about 1 month ago)
• Topics: burpsuite, nginx, path-traversal
• Language: Python
• Homepage:
• Size: 88.9 KB
• Stars: 253
• Watchers: 7
• Forks: 36
• Open Issues: 1
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

Awesome Lists containing this project

• awesome-bugbounty-tools - off-by-slash - Burp extension to detect alias traversal via NGINX misconfiguration at scale. (Exploitation / Directory Traversal)
• awesome-burp-extensions - off-by-slash - Burp extension to detect alias traversal via NGINX misconfiguration at scale. (Vulnerability Specific Extensions / Directory Traversal)

README

        
# off-by-slash

Burp extension to detect alias traversal via NGINX misconfiguration at scale. Requires Burp Professional.

![Issue](issue.png?raw=true "off-by-slash in Burp 2.0")

## Usage

1. git clone https://github.com/bayotop/off-by-slash/

2. Burp -> Extender -> Add -> find and select `off-by-slash.py`

The extension implements an active scanner check. Simply run a new scan, preferably with an "Audit checks - extensions only" configuration, on static resources identified via Burp's crawler. Alternatively, use `scrape.py` with a list of URLs to scrape static resources from. The results can be directly passed to a new Burp scan (Burp 2.0).

## Description

*https://i.blackhat.com/us-18/Wed-August-8/us-18-Orange-Tsai-Breaking-Parser-Logic-Take-Your-Path-Normalization-Off-And-Pop-0days-Out-2.pdf*

A server is assumed to be vulnerable if a request to an existing path like `https://example.com/static../` returns the same response as `https://example.com/`. To eliminate false positives the misconfiguration has to be confirmed by successfully requesting an existing resource via path traversal. This is done as follows:

For the URL https://example.com/folder1/folder2/static/main.css it generates the following links:

```

https://example.com/folder1../folder1/folder2/static/main.css

https://example.com/folder1../%s/folder2/static/main.css

https://example.com/folder1/folder2../folder2/static/main.css

https://example.com/folder1/folder2../%s/static/main.css

https://example.com/folder1/folder2/static../static/main.css

https://example.com/folder1/folder2/static../%s/main.css

```

Where `%s` are common directories used in alias paths based on around 9500 nginx configuration files from GH (thanks [@TomNomNom](https://twitter.com/TomNomNom)), see directories.txt.