Fetch-url-file-3a-2f-2f-2froot-2f.aws-2fconfig __exclusive__ -

app.get('/fetch-image', async (req, res) => const imageUrl = req.query.url; const response = await fetch(imageUrl); const buffer = await response.buffer(); res.set('Content-Type', 'image/jpeg'); res.send(buffer); );

After one decode: file%3A%2F%2F%2Froot%2F.aws%2Fconfig After second decode: file:///root/.aws/config

Note that the original keyword uses - instead of % – this might be a custom encoding scheme used by a specific framework or a mistake. In real attacks, percent-encoding is standard.

The following example demonstrates how a poorly configured back-end script allows this type of file fetching exploit to succeed: fetch-url-file-3A-2F-2F-2Froot-2F.aws-2Fconfig

from urllib.parse import urlparse

Do you use on your server, or are you utilizing IAM instance profiles ?

from pathlib import Path p = Path("/root/.aws/config") if p.exists(): print(p.read_text()) else: print("File not found") from pathlib import Path p = Path("/root/

[default] region = us-east-1 output = json

This payload typically targets two major classes of web vulnerabilities: Local File Inclusion (LFI)

?page=../../../../root/.aws/config

[profile prod] region = eu-west-1 output = json

Write in English, long form (1500+ words). Use headings, subheadings, code blocks. Be educational. The Hidden Danger of 'fetch-url-file-3A-2F-2F-2Froot-2F.aws-2Fconfig': Understanding Local File Inclusion and AWS Credential Theft