Incorrect validation of root DNSSEC public keys in github.com/peterzen/goresolver

Vulnerability

Analysis

The goresolver library, a DNSSEC validating resolver, contains a critical flaw in its validation logic. The package does not properly verify the RRSIG header name against the queried domain, nor does it validate the root DNSSEC public keys [1][2]. This allows an attacker to present a self-signed root key and delegation chain, bypassing the chain of trust entirely.

Attack

Vector

An attacker can exploit this by forging an RRSIG record for any domain, using a valid domain they control. The library fails to check that the RRSIG's header name matches the queried domain name, instead using the header name directly for chain-of-trust verification [3]. For example, when a victim queries for example.com, an attacker who owns pwn.com can generate a valid RRSIG for a fake response set and attach it with the header name pwn.com. The library then queries for the DNSKEY of pwn.com and verifies the forged response, incorrectly accepting it as valid for example.com.

Impact

Successful exploitation allows an attacker to cause the library to report successful DNSSEC validation for invalid, attacker-controlled records. This effectively enables DNS spoofing and man-in-the-middle attacks, compromising the integrity of DNS responses validated by the library.

Mitigation

Status

As of the latest advisory, all versions of goresolver are affected, and no fix has been released [4]. Users of the library should consider it insecure for DNSSEC validation until a patch is applied, and may need to implement additional validation checks or switch to a different resolver library.