CVE-2015-5230 in PowerDNS
Summary
by MITRE
The DNS packet parsing/generation code in PowerDNS (aka pdns) Authoritative Server 3.4.x before 3.4.6 allows remote attackers to cause a denial of service (crash) via crafted query packets.
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Analysis
by VulDB Data Team • 11/23/2024
The vulnerability identified as CVE-2015-5230 affects PowerDNS authoritative server version 3.4.x prior to 3.4.6, representing a critical denial of service flaw in DNS packet processing. This issue stems from inadequate validation within the DNS packet parsing and generation mechanisms that handle incoming query packets from remote attackers. The flaw specifically manifests when the server encounters malformed or specially crafted DNS query packets that exploit weaknesses in the packet handling code, leading to unexpected server crashes and complete service disruption. The vulnerability impacts the core functionality of authoritative DNS servers that rely on PowerDNS software, potentially affecting thousands of domains and services dependent on proper DNS resolution.
The technical root cause of this vulnerability lies in insufficient input validation during DNS packet processing within the PowerDNS codebase. When the authoritative server receives a malformed DNS query packet, the parsing routines fail to properly handle edge cases or invalid packet structures, causing the application to terminate unexpectedly. This represents a classic buffer over-read or improper state handling vulnerability that falls under CWE-129, which addresses improper validation of input ranges. The flaw demonstrates poor defensive programming practices where the code does not adequately validate packet headers, lengths, or content structures before processing them, creating an execution path that leads to memory corruption or invalid memory access patterns. Attackers can exploit this by sending specifically crafted DNS queries that trigger the vulnerable code path, causing the server process to crash and require manual restart to restore service availability.
The operational impact of CVE-2015-5230 extends far beyond simple service disruption, as authoritative DNS servers form the backbone of internet infrastructure. When exploited, this vulnerability can cause cascading failures across dependent services, as DNS resolution becomes unavailable for all domains hosted on the compromised server. Organizations relying on PowerDNS authoritative servers for critical operations face potential business disruption, customer service degradation, and increased operational overhead from manual intervention required to restore services. The vulnerability is particularly concerning in cloud environments and managed DNS services where multiple domains share the same authoritative server instances, amplifying the potential impact of a single exploit. From an attack perspective, this vulnerability aligns with ATT&CK technique T1499.004 for network denial of service, representing a straightforward exploitation method that requires minimal technical skill while delivering maximum operational impact.
Mitigation strategies for CVE-2015-5230 should prioritize immediate software updates to PowerDNS version 3.4.6 or later, which contain the necessary patches addressing the packet parsing flaws. Organizations should also implement network-level protections such as DNS query filtering and rate limiting to reduce the impact of potential exploitation attempts. Additionally, deploying intrusion detection systems that monitor for suspicious DNS query patterns can help identify exploitation attempts before they cause service disruption. The vulnerability highlights the importance of input validation and defensive programming practices, aligning with security best practices outlined in OWASP Top Ten and NIST cybersecurity frameworks. Regular security assessments and vulnerability scanning should be implemented to identify similar weaknesses in other DNS server implementations, as similar issues may exist in other software components handling network packet processing. Organizations should also consider implementing redundant DNS server configurations to minimize the impact of single points of failure, ensuring business continuity even when individual servers are compromised by such vulnerabilities.