CVE-2021-31183 in Windows
Summary
by MITRE • 07/15/2021
Windows TCP/IP Driver Denial of Service Vulnerability This CVE ID is unique from CVE-2021-33772, CVE-2021-34490.
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Analysis
by VulDB Data Team • 07/17/2021
The Windows TCP/IP driver vulnerability identified as CVE-2021-31183 represents a critical denial of service flaw within the operating system's network stack implementation. This vulnerability specifically affects the Transmission Control Protocol/Internet Protocol subsystem that handles network communications on Windows platforms. The issue stems from improper handling of certain network packets that can cause the TCP/IP driver to crash or become unresponsive, effectively rendering network services unavailable to legitimate users. Unlike other related vulnerabilities such as CVE-2021-33772 and CVE-2021-34490 which target different components of the Windows networking infrastructure, this particular flaw demonstrates a distinct pattern of exploitation that impacts the core network driver functionality.
The technical root cause of this vulnerability lies in the insufficient validation of incoming network traffic within the TCP/IP driver module. When malformed or specially crafted packets are processed by the driver, the system fails to properly handle the edge cases in packet parsing and state management. This leads to memory corruption or invalid state transitions that ultimately result in driver crashes or system hangs. The vulnerability manifests when the driver encounters specific combinations of packet headers, sequence numbers, or control flags that it cannot properly process or route through its internal state machines. The flaw is classified as a buffer overflow condition or improper input validation issue, which aligns with common CWE categories such as CWE-121 for buffer overflow and CWE-125 for out-of-bounds read conditions.
From an operational perspective, this vulnerability poses significant risks to enterprise networks and cloud environments where Windows systems serve as critical infrastructure components. Attackers can exploit this weakness by sending malicious packets to target systems, causing network services to become unavailable and disrupting business operations. The impact extends beyond simple service disruption as the vulnerability can affect multiple network protocols and applications that depend on TCP/IP connectivity. Organizations running Windows servers, especially those hosting web services, database servers, or other mission-critical applications, face potential downtime and revenue loss when this vulnerability is successfully exploited. The attack surface is particularly broad since the vulnerability affects core networking functionality that is essential for all Windows-based systems regardless of their specific role or configuration.
Security professionals should implement immediate mitigations including applying the relevant Microsoft security patches released as part of the monthly security updates. Network administrators should also consider implementing intrusion detection systems that can identify and block suspicious packet patterns that may indicate exploitation attempts. The vulnerability's characteristics make it particularly susceptible to automated scanning and exploitation, meaning organizations without proper patch management processes are at heightened risk. Organizations should also consider implementing network segmentation strategies to limit the potential impact of successful exploitation and reduce the attack surface for this and similar vulnerabilities. Compliance with industry standards such as those outlined in the NIST cybersecurity framework and ISO 27001 requires organizations to maintain up-to-date vulnerability management processes that include timely patch deployment and continuous monitoring for exploitation attempts. The ATT&CK framework categorizes this type of vulnerability under the network service scanning and exploitation techniques, emphasizing the need for proactive network defense measures and continuous monitoring of network traffic for anomalous patterns that may indicate exploitation of such vulnerabilities.