CVE-2011-1970 in Windows
Summary
by MITRE
The DNS server in Microsoft Windows Server 2003 SP2 and Windows Server 2008 SP2, R2, and R2 SP1 does not properly initialize memory, which allows remote attackers to cause a denial of service (service outage) via a query for a nonexistent domain, aka "DNS Uninitialized Memory Corruption Vulnerability."
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Analysis
by VulDB Data Team • 03/19/2021
The DNS server implementation in Microsoft Windows Server 2003 SP2 and Windows Server 2008 SP2, R2, and R2 SP1 contains a critical memory initialization flaw that manifests as a vulnerability in the domain name resolution service. This vulnerability stems from improper memory handling during the processing of DNS queries for non-existent domains, creating a condition where uninitialized memory segments are accessed or manipulated. The flaw represents a classic memory corruption vulnerability that can be exploited by remote attackers without authentication, making it particularly dangerous in networked environments where DNS services are exposed to external traffic.
The technical nature of this vulnerability aligns with CWE-457: Use of Uninitialized Variable, where the DNS server fails to properly initialize memory structures before utilizing them during query processing. When a malicious actor sends a specially crafted DNS query for a nonexistent domain, the server's memory management routines do not adequately prepare the memory segments, leading to unpredictable behavior. The uninitialized memory may contain residual data from previous operations, causing the DNS service to behave erratically and ultimately crash. This memory corruption occurs within the core DNS server component, specifically during the handling of malformed or edge-case queries that would typically be processed without issue.
The operational impact of this vulnerability extends beyond simple service disruption, as it creates a reliable denial of service condition that can be triggered remotely. Attackers can repeatedly send queries for non-existent domains to cause the DNS server to crash and restart, effectively rendering the service unavailable to legitimate users. This vulnerability particularly affects enterprise environments where DNS servers are critical infrastructure components, as the service outage can cascade through network operations and potentially impact authentication services, email delivery, and other systems dependent on DNS resolution. The vulnerability's remote exploitability means that attackers do not need physical access or local network privileges to trigger the condition, making it a significant threat vector for network-based attacks.
Mitigation strategies for this vulnerability should include immediate deployment of Microsoft security patches that address the memory initialization issue in the DNS server implementation. Organizations should also implement network segmentation to limit exposure of DNS servers to untrusted networks, and consider deploying DNS server hardening measures such as query rate limiting and access control lists. From an operational perspective, monitoring systems should be configured to detect unusual DNS query patterns that might indicate exploitation attempts, and incident response procedures should be established to quickly address service outages. The vulnerability demonstrates the importance of proper memory management in server applications and highlights the need for regular security updates and vulnerability assessments to maintain network resilience against similar memory corruption threats. This vulnerability also underscores the broader ATT&CK technique of service stoppage and denial of service, where attackers target critical infrastructure services to disrupt normal operations and create opportunities for further exploitation.