Envoy vulnerable to crash for scoped ip address during DNS

Summary

Calling Utility::getAddressWithPort with a scoped IPv6 addresses causes a crash. This utility is called in the data plane from the original_src filter and the dns filter.

Details

The crashing function is Utility::getAddressWithPort. The crash occurs if a string containing a scoped IPv6 address is passed to this function.

This vulnerability affects:

1. The original src filter: If the filter is configured and the original source is a scoped IPv6 address, it will cause a crash.
2. DNS response address resolution: If a DNS response contains a scoped IPv6 address, this will also trigger the crash.

PoC

To reproduce the vulnerability:

1. Method A (Original Src Filter): Configure the original src filter in Envoy and provide a scoped IPv6 address as the original source.
2. Method B (DNS Resolution): Trigger a DNS resolution process within Envoy where the DNS response contains a scoped IPv6 address.

Impact

This is a Denial of Service (DoS) vulnerability. It impacts users who have the original src filter configured or whose Envoy instances resolve addresses from DNS responses that may contain scoped IPv6 addresses.