CVE-2008-3217 in Recursor
Summary
by MITRE
PowerDNS Recursor before 3.1.6 does not always use the strongest random number generator for source port selection, which makes it easier for remote attack vectors to conduct DNS cache poisoning. NOTE: this is related to incomplete integration of security improvements associated with addressing CVE-2008-1637.
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Analysis
by VulDB Data Team • 08/01/2021
The vulnerability identified as CVE-2008-3217 affects PowerDNS Recursor versions prior to 3.1.6, specifically addressing weaknesses in the random number generation mechanism used for source port selection during DNS resolution processes. This flaw represents a significant security concern that directly impacts the integrity of DNS caching operations and creates exploitable conditions for malicious actors seeking to manipulate DNS responses.
The technical flaw stems from inadequate implementation of cryptographic randomness in the source port selection algorithm. When PowerDNS Recursor generates source ports for outgoing DNS queries, it fails to consistently utilize the strongest available random number generator, instead potentially falling back to weaker alternatives or less secure entropy sources. This inconsistency creates predictable patterns in port selection that adversaries can exploit to mount cache poisoning attacks. The vulnerability is particularly concerning because it represents incomplete remediation of a related issue, CVE-2008-1637, where security improvements were partially implemented but not fully integrated into the source port selection mechanism.
The operational impact of this vulnerability extends beyond simple cache poisoning attempts, as it fundamentally compromises the trustworthiness of DNS resolution processes. Attackers can leverage predictable source port patterns to inject malicious DNS responses into caches, potentially redirecting users to fraudulent websites or disrupting network services. This weakness particularly affects environments where DNS security is paramount, such as enterprise networks, internet service providers, and any infrastructure relying on accurate DNS resolution for critical operations. The vulnerability creates a persistent risk that can be exploited across multiple network segments and affects the overall security posture of systems dependent on PowerDNS Recursor.
Mitigation strategies should focus on immediate deployment of PowerDNS Recursor version 3.1.6 or later, which contains the complete remediation for both CVE-2008-3217 and CVE-2008-1637. Organizations should also implement additional network-level protections such as DNSSEC validation and consider deploying monitoring solutions to detect anomalous DNS traffic patterns that might indicate cache poisoning attempts. The vulnerability aligns with CWE-330, which addresses the use of insufficiently random values in security-sensitive contexts, and maps to ATT&CK technique T1071.004 for application layer protocol: DNS, specifically targeting the exploitation of DNS cache poisoning vulnerabilities. Network administrators should also review their existing security configurations and ensure proper entropy sources are available to support robust random number generation across all security-critical applications.
This vulnerability demonstrates the critical importance of comprehensive security patching and the dangers of partial remediation efforts that leave residual weaknesses in complex systems. The interdependence between related security issues highlights the need for thorough testing and validation of security improvements before deployment, as incomplete fixes can create more dangerous exposure than the original vulnerabilities themselves. Organizations must maintain rigorous security update procedures and conduct regular vulnerability assessments to prevent similar issues from compromising their DNS infrastructure security.