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Security controls bypass or absence - Cloudflare

Description

It is possible to make requests directly to the servers IP and thus bypass Cloudflare.

Impact

  • Extract technical information that Cloudflare masks and thus expand the attack surface.
  • Make malicious requests that are rejected by Cloudflare.
  • Perform DDoS attacks by evading the service that protects against them.

Recommendation

Redirect any request to the server to the security service.

Threat

Unauthorized user from the Internet.

Expected Remediation Time

⌚ 60 minutes.

Score

Default score using CVSS 3.1. It may change depending on the context of the vulnerability.

Base

  • Attack vector: N
  • Attack complexity: L
  • Privileges required: N
  • User interaction: N
  • Scope: U
  • Confidentiality: L
  • Integrity: N
  • Availability: L

Temporal

  • Exploit code madurity: U
  • Remediation level: X
  • Report confidence: R

Result

  • Vector string: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:L/E:U/RL:X/RC:R
  • Score:
    • Base: 6.5
    • Temporal: 5.7
  • Severity:
    • Base: Medium
    • Temporal: Medium

Code Examples

Compliant code

The cloudfare is securely configured

tunnel: The tunnel UUID
credentials-file: /path/credentials.json
warp-routing:
enabled: true
ingress:
- hostname: yourhost
service: http://localhost:80
- service: http_status:404

Non compliant code

The cloudfare uses the server as the default ingress

tunnel: The tunnel UUID
credentials-file: /path/credentials.json
warp-routing:
enabled: true
ingress:
- hostname: gitlab.widgetcorp.tech
service: http://localhost:80

Requirements