In NLnet Labs Unbound 1.18.0 up to and including 1.25.1, when Unbound listens on a 'proxy-protocol-port' interface with 'answer-cookie: yes', the RFC 9018 server-cookie SipHash is computed over the proxy's wire address instead of the PROXYv2-declared client. One server cookie obtained through a given proxy node therefore validates for every PROXYv2-declared source behind that node. On a UDP+proxy-protocol front, an off-path attacker can harvest one cookie with a single legitimate query, then replay it under any spoofed source and pass DNS Cookie checks that were deployed to defeat this in the first place.

In NLnet Labs Unbound 1.18.0 up to and including 1.25.1, when Unbound listens on a 'proxy-protocol-port' interface with 'answer-cookie: yes', the RFC 9018 server-cookie SipHash is computed over the proxy's wire address instead of the PROXYv2-declared client. One server cookie obtained through a given proxy node therefore validates for every PROXYv2-declared source behind that node. On a UDP+proxy-protocol front, an off-path attacker can harvest one cookie with a single legitimate query, then replay it under any spoofed source and pass DNS Cookie checks that were deployed to defeat this in the first place.

libunbound8-1.25.2-1.1 on GA media

unbound: Unbound: Denial of Service via assertion failure in DNS-over-QUIC environments unbound: Unbound: Denial of Service via improper validation of DNS-over-QUIC client length unbound: Unbound: Denial of Service via crafted DNSCrypt query unbound: Unbound: Denial of Service via terminated DNS-over-QUIC queries unbound: Unbound: DNS cache integrity issue unbound: Unbound: Denial of Service due to 'harden-below-nxdomain' logic bypass unbound: Unbound: Cache poisoning via insufficient RRSIG.Labels validation and premature cache writes unbound: Unbound: Information disclosure via DNSSEC wildcard replay unbound: Unbound: Denial of Service via DNSSEC query amplification bypass unbound: Unbound: Denial of Service due to freed pointer dereference in DNS-over-TLS handling unbound: Unbound: Insecure DNS redirection via spoofed DNS answers unbound: Unbound: DNS response policy replacement via hostname spoofing unbound: NLnet Labs Unbound: Denial of Service via crafted DNS glue records unbound: Unbound: DNS cache poisoning via UDP source port predictability unbound: Unbound: Denial of service due to memory corruption under specific configurations. unbound: Unbound: DNS Cookie security bypass via incorrect server cookie calculation unbound: Unbound: Information disclosure due to local policy bypass via unbound-control unbound: Unbound: Denial of Service via crafted DNS responses with expired records unbound: Unbound: Denial of Service via malformed EDNS Report-Channel option unbound:…

Security update for unbound

Affected: Ubuntu:Pro:14.04:LTS: unbound, Ubuntu:Pro:16.04:LTS: unbound, Ubuntu:Pro:18.04:LTS: unbound, Ubuntu:Pro:20.04:LTS: unbound, Ubuntu:22.04:LTS: unbound, Ubuntu:24.04:LTS: unbound, Ubuntu:26.04:LTS: unbound

In NLnet Labs Unbound 1.18.0 up to and including 1.25.1, when Unbound listens on a 'proxy-protocol-port' interface with 'answer-cookie: yes', the RFC 9018 server-cookie SipHash is computed over the proxy's wire address instead of the PROXYv2-declared client. One server cookie obtained through a given proxy node therefore validates for every PROXYv2-declared source behind that node. On a UDP+proxy-protocol front, an off-path attacker can harvest one cookie with a single legitimate query, then replay it under any spoofed source and pass DNS Cookie checks that were deployed to defeat this in the first place.

Ein Angreifer kann mehrere Schwachstellen in Unbound ausnutzen, um einen Denial of Service Angriff durchzuführen, um Informationen offenzulegen, um Daten zu manipulieren, und um Sicherheitsvorkehrungen zu umgehen.