CVE-2023-7008 in systemd-resolved
Summary
by MITRE • 12/23/2023
A vulnerability was found in systemd-resolved. This issue may allow systemd-resolved to accept records of DNSSEC-signed domains even when they have no signature, allowing man-in-the-middles (or the upstream DNS resolver) to manipulate records.
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Analysis
by VulDB Data Team • 05/08/2025
The vulnerability identified as CVE-2023-7008 resides within systemd-resolved, a critical component of the systemd suite responsible for managing DNS resolution on Linux systems. This flaw represents a significant security weakness in the DNS security infrastructure that could undermine the integrity of DNS responses. The issue specifically affects how systemd-resolved processes DNS responses from authoritative servers, creating a potential pathway for malicious actors to compromise the DNS resolution process without proper authentication or validation.
The technical flaw manifests when systemd-resolved accepts DNS records from domains that are signed with DNSSEC but fails to properly validate that these records actually contain valid signatures. This condition allows for a scenario where DNS responses can be manipulated by either man-in-the-middle attackers or compromised upstream DNS resolvers. The vulnerability stems from insufficient validation logic that should ensure DNSSEC-signed records possess valid cryptographic signatures before accepting them as trustworthy. When DNSSEC is properly implemented, signed records must contain valid signatures that can be verified against the zone's public key, but this validation mechanism has been bypassed in the affected implementation.
The operational impact of CVE-2023-7008 extends beyond simple DNS resolution failures, potentially enabling sophisticated attacks such as DNS cache poisoning or more targeted man-in-the-middle operations. Attackers could exploit this weakness to redirect users to malicious websites by manipulating DNS responses without detection, particularly affecting systems that rely on DNSSEC for security validation. The vulnerability is especially concerning in enterprise environments where DNSSEC is implemented as part of security policies, as it effectively neutralizes the security benefits provided by DNSSEC validation. This weakness could allow attackers to bypass DNS security controls and gain unauthorized access to systems or data.
Systems utilizing systemd-resolved version 252 or earlier are vulnerable to this issue, making it particularly widespread across Linux distributions that have not yet updated their systemd packages. The vulnerability aligns with CWE-310, which addresses cryptographic weaknesses in the validation of digital signatures and authentication mechanisms. From an adversary perspective, this vulnerability maps to ATT&CK technique T1071.004 for DNS tunneling and T1566 for phishing attacks, as it enables attackers to manipulate DNS responses to redirect traffic to malicious endpoints. Organizations should prioritize patching this vulnerability immediately, as it provides attackers with a straightforward method to compromise DNS security. The recommended mitigation includes updating to systemd version 253 or later, which contains the necessary fixes to properly validate DNSSEC signatures. Additionally, system administrators should implement network monitoring to detect anomalous DNS behavior that might indicate exploitation attempts, and consider implementing additional DNS security measures such as DNS Firewall or DNS over HTTPS to provide layered protection against DNS-based attacks.