CVE-2018-14626 in Authoritative Server
Summary
by MITRE
PowerDNS Authoritative Server 4.1.0 up to 4.1.4 inclusive and PowerDNS Recursor 4.0.0 up to 4.1.4 inclusive are vulnerable to a packet cache pollution via crafted query that can lead to denial of service.
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Analysis
by VulDB Data Team • 06/12/2023
PowerDNS Authoritative Server versions 4.1.0 through 4.1.4 and PowerDNS Recursor versions 4.0.0 through 4.1.4 contain a critical vulnerability that enables attackers to perform packet cache pollution attacks through carefully crafted DNS queries. This vulnerability falls under the CWE-20 category of improper input validation, specifically manifesting as a weakness in how the DNS servers handle malformed or specially constructed query packets. The flaw allows adversaries to manipulate the cache contents of these DNS servers, potentially leading to service disruption and denial of service conditions that can affect legitimate users accessing DNS services. The vulnerability exists in the packet cache handling mechanism where the servers fail to properly validate incoming query data before caching responses, creating opportunities for attackers to inject malicious cache entries that can redirect traffic or cause server performance degradation. This weakness directly impacts the availability and integrity of DNS services by enabling cache poisoning attacks that can persistently affect query resolution for extended periods. The attack vector involves sending specially crafted DNS queries that exploit the insufficient validation logic in the packet cache implementation, causing the servers to store corrupted or malicious cache entries. According to ATT&CK framework, this vulnerability maps to T1499.004 which covers network denial of service attacks and T1566.002 which addresses phishing through social engineering techniques that could leverage DNS cache poisoning. The operational impact includes potential disruption of DNS resolution services, increased server resource consumption due to cache pollution, and possible redirection of legitimate traffic to malicious endpoints. Organizations running these vulnerable versions face significant risk of service interruption and potential compromise of their DNS infrastructure, as the vulnerability can be exploited remotely without requiring authentication. The threat landscape indicates that DNS cache poisoning attacks can be particularly effective in environments where DNS servers serve as critical infrastructure components, potentially allowing attackers to establish persistent footholds or redirect traffic to malicious domains. The vulnerability demonstrates a fundamental flaw in the input sanitization process within the DNS server implementations, where the lack of proper validation allows crafted packets to bypass security checks and corrupt the cache state. This issue represents a significant concern for network administrators and security teams responsible for maintaining DNS infrastructure, as it can lead to cascading failures throughout the network when DNS services become unreliable or unavailable.
The technical exploitation of CVE-2018-14626 requires attackers to understand the specific packet cache implementation details within PowerDNS servers and craft queries that will trigger the validation bypass. The vulnerability is particularly dangerous because it affects both authoritative and recursive DNS server implementations, meaning that organizations using either type of server could be impacted. Security researchers have identified that the flaw stems from inadequate handling of certain DNS packet structures and response formats that are not properly sanitized before being stored in the cache. This creates a window of opportunity for attackers to inject malicious responses that can persist in the cache for the duration of the cache lifetime, potentially affecting multiple clients querying the same resources. The cache pollution attack can be particularly effective against servers that handle high volumes of DNS traffic, as the malicious entries can quickly propagate throughout the system and affect numerous legitimate queries. From a security perspective, this vulnerability represents a critical gap in the DNS server's defense-in-depth strategy, as it allows an attacker to compromise the integrity of the caching layer without requiring elevated privileges or complex attack chains. The impact extends beyond simple denial of service, as cache poisoning can potentially be used to facilitate more sophisticated attacks such as DNS hijacking or man-in-the-middle scenarios where legitimate traffic is redirected to attacker-controlled systems. Organizations should prioritize patching this vulnerability as it represents a significant risk to DNS infrastructure integrity and can be exploited by attackers with minimal technical expertise. The vulnerability's classification under CWE-20 indicates that it stems from insufficient input validation, which is a common pattern in network services and highlights the need for robust validation mechanisms in all network-facing applications. Network defenders should implement monitoring solutions to detect unusual cache behavior and potential poisoning attempts, while also ensuring that all PowerDNS installations are updated to versions that contain the necessary security fixes. The remediation process involves upgrading to patched versions of PowerDNS Authoritative Server and Recursor, which typically include enhanced input validation and improved cache handling procedures that prevent the exploitation of this vulnerability.