NLnet Labs Unbound, up to and including version 1.16.1 is vulnerable to a novel type of the ghost domain names attack. The vulnerability works by targeting an Unbound instance. Unbound is queried for a subdomain of a rogue domain name. The rogue nameserver returns delegation information for the subdomain that updates Unbounds delegation cache. This action can be repeated before expiry of the delegation information by querying Unbound for a second level subdomain which the rogue nameserver provides new delegation information. Since Unbound is a child-centric resolver, the ever-updating child delegation information can keep a rogue domain name resolvable long after revocation. From version 1.16.2 on, Unbound checks the validity of parent delegation records before using cached delegation information.
According to WASC, “Insufficient Session Expiration is when a web site permits an attacker to reuse old session credentials or session IDs for authorization.”
| Name | Vendor | Start Version | End Version |
|---|---|---|---|
| Unbound | Nlnetlabs | * | 1.16.2 (excluding) |
| Red Hat Enterprise Linux 8 | RedHat | unbound-0:1.16.2-2.el8 | * |
| Red Hat Enterprise Linux 8.6 Extended Update Support | RedHat | unbound-0:1.7.3-17.el8_6.5 | * |
| Red Hat Enterprise Linux 9 | RedHat | unbound-0:1.16.2-2.el9 | * |
| Unbound | Ubuntu | bionic | * |
| Unbound | Ubuntu | devel | * |
| Unbound | Ubuntu | esm-infra-legacy/trusty | * |
| Unbound | Ubuntu | esm-infra/xenial | * |
| Unbound | Ubuntu | focal | * |
| Unbound | Ubuntu | jammy | * |
| Unbound | Ubuntu | kinetic | * |
| Unbound | Ubuntu | lunar | * |
| Unbound | Ubuntu | mantic | * |
| Unbound | Ubuntu | noble | * |
| Unbound | Ubuntu | trusty | * |
| Unbound | Ubuntu | trusty/esm | * |
| Unbound | Ubuntu | upstream | * |
| Unbound | Ubuntu | xenial | * |