Skip to Content [alt-c]


In reply to Preventing Server Side Request Forgery in Golang

Reader Arkadiy Tetelman on 2019-12-21 at 19:21:

I was googling how to prevent SSRF in Golang and found this article published only yesterday - very serendipitous for me!

Your IPv6 blocking is missing a few other reserved addresses though - in particular it's missing the ipv4-mapped and ipv4-compatible ipv6 addresses. For instance I could make a request to the ipv6 address ::ffff: and access your cloud provider metadata service.

If it's helpful here's the ipv6 denylist I use in my SSRF ruby gem:

In any case this post / the network hooking was extremely helpful for me - thank you!


Post a Reply

Your comment will be public. To contact me privately, email me. Please keep your comment polite, on-topic, and comprehensible. Your comment may be held for moderation before being published.

(Optional; will be published)

(Optional; will not be published)

(Optional; will be published)

  • Blank lines separate paragraphs.
  • Lines starting with > are indented as block quotes.
  • Lines starting with two spaces are reproduced verbatim (good for code).
  • Text surrounded by *asterisks* is italicized.
  • Text surrounded by `back ticks` is monospaced.
  • URLs are turned into links.
  • Use the Preview button to check your formatting.