Impact

Skipper prior to version v0.13.236 is vulnerable to server-side request forgery (SSRF). An attacker can exploit a vulnerable version of proxy to access the internal metadata server or other unauthenticated URLs by adding an specific header (X-Skipper-Proxy) to the http request.

Patches

The problem was patched in version https://github.com/zalando/skipper/releases/tag/v0.13.237.
Users need to upgrade to skipper >=v0.13.237.

Workarounds

Use dropRequestHeader("X-Skipper-Proxy") filter

References

https://github.com/zalando/skipper/releases/tag/v0.13.237

For more information

If you have any questions or comments about this advisory:

• Open an issue in https://github.com/zalando/skipper/issues/new/choose
• Chat with us in slack: https://app.slack.com/client/T029RQSE6/C82Q5JNH5

References

• GHSA-f2rj-m42r-6jm2
• https://nvd.nist.gov/vuln/detail/CVE-2022-38580
• https://gist.github.com/Fadavvi/9fffcfa4aaa9e25b77cfe7b3044b2857#file-cve-2022-38580
• https://pastebin.com/dXxpgPAK
• http://skipper.com
• http://zalando.com
• zalando/skipper#2058
• https://github.com/zalando/skipper/releases/tag/v0.13.237
• https://pkg.go.dev/vuln/GO-2022-1086
• zalando/skipper@8426343
• http://packetstormsecurity.com/files/171546/X-Skipper-Proxy-0.13.237-Server-Side-Request-Forgery.html