CVE-2022-30256 is a high-severity vulnerability affecting MaraDNS Deadwood versions up to 3.5.0021. The issue involves unintended domain name resolution behavior, specifically a variant V1 flaw where revoked domain names—such as expired domains or malicious domains that have been taken down—remain resolvable for an extended period. This persistence occurs despite existing mitigation patches aimed at addressing "Ghost" domain names, which are domains that should no longer resolve but continue to do so due to caching or DNS server misbehavior. The vulnerability exploits the way MaraDNS Deadwood handles domain revocation and caching, allowing these revoked domains to be resolved in DNS queries. Because the exploitation conforms to de facto DNS specifications and operational practices, it can bypass typical DNS security controls and patches. The CVSS 3.1 score of 7.5 (AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N) indicates that the vulnerability can be exploited remotely without authentication or user interaction, does not impact confidentiality or availability, but causes a high impact on integrity. Specifically, the integrity impact arises from the potential for DNS responses to be manipulated or spoofed by resolving revoked domains, which could lead to redirection to malicious sites, phishing, or man-in-the-middle attacks. No known exploits are currently reported in the wild, but the widespread use of MaraDNS Deadwood in DNS infrastructure means the vulnerability could have broad implications if weaponized. The vulnerability is linked to CWE-672, which relates to operations on resources after they have been invalidated or revoked, highlighting a logic flaw in domain resolution lifecycle management.

For European organizations, the impact of CVE-2022-30256 could be significant, especially for those relying on MaraDNS Deadwood as part of their DNS infrastructure, including ISPs, enterprises, and critical infrastructure providers. The ability to resolve revoked or malicious domains can facilitate phishing attacks, malware distribution, and redirection of legitimate traffic to attacker-controlled sites, undermining trust in DNS resolution and potentially leading to data integrity breaches or credential theft. Since DNS is foundational to internet operations, this vulnerability could disrupt secure communications and enable sophisticated supply chain or espionage attacks. Organizations in sectors such as finance, government, telecommunications, and energy—where DNS integrity is critical—are particularly at risk. The persistence of revoked domain resolution also complicates incident response and domain takedown efforts, potentially allowing attackers to maintain footholds or evade detection. Given the vulnerability does not require authentication or user interaction, attackers can exploit it remotely at scale, increasing the threat surface. Although no active exploits are reported, the potential for widespread misuse remains high, especially if attackers develop automated tools to leverage this flaw.

To mitigate CVE-2022-30256 effectively, European organizations should: 1) Immediately audit their DNS infrastructure to identify the use of MaraDNS Deadwood and assess the version in deployment. 2) Apply any available patches or updates from MaraDNS developers; if no official patch exists, consider upgrading to alternative DNS software with robust domain revocation handling. 3) Implement strict DNS response validation and monitoring to detect anomalous resolutions of revoked or expired domains, including deploying DNSSEC validation to ensure authenticity of DNS data. 4) Employ DNS filtering and threat intelligence feeds to block known malicious domains proactively, reducing the risk posed by unintended resolution. 5) Regularly clear DNS caches and reduce TTL values for sensitive zones to minimize the window during which revoked domains remain resolvable. 6) Enhance network-level monitoring for suspicious DNS queries and responses that could indicate exploitation attempts. 7) Coordinate with domain registrars and cybersecurity authorities to expedite domain revocation and takedown processes, ensuring that DNS infrastructure promptly reflects domain status changes. 8) Educate security teams about this vulnerability’s implications to improve detection and response capabilities. These steps go beyond generic advice by focusing on domain lifecycle management, DNS cache hygiene, and leveraging DNSSEC and threat intelligence integration.