CVE-2021-28443 in Windows
Summary
by MITRE • 04/14/2021
Windows Console Driver Denial of Service Vulnerability This CVE ID is unique from CVE-2021-28438.
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Analysis
by VulDB Data Team • 04/16/2021
The Windows Console Driver Denial of Service Vulnerability CVE-2021-28443 represents a critical security flaw within the Windows operating system's console subsystem that specifically affects the condrv.sys driver component. This vulnerability resides in the Windows Console Driver which is responsible for managing console input and output operations across various applications and system processes. The issue manifests when the console driver fails to properly handle certain malformed input sequences or memory allocation scenarios, leading to system instability and potential denial of service conditions. The vulnerability is particularly concerning because console drivers are fundamental components that support numerous system functions including command prompt operations, PowerShell execution, and various console-based applications that form the backbone of system administration and user interaction.
The technical flaw underlying CVE-2021-28443 stems from improper validation of input parameters within the console driver's memory management routines and input processing logic. When malicious or malformed input sequences are processed by the condrv.sys driver, the system encounters memory corruption or buffer overflow conditions that cause the driver to crash or become unresponsive. This vulnerability is classified under CWE-125 as an out-of-bounds read condition and potentially CWE-787 as an out-of-bounds write condition, depending on the specific exploitation vector. The flaw occurs during the processing of console input/output operations where the driver does not adequately validate the size or content of incoming data streams, allowing attackers to craft specific inputs that trigger memory corruption within the driver's execution context.
The operational impact of this vulnerability extends beyond simple denial of service conditions as it can severely disrupt system functionality and user productivity across affected Windows environments. Systems running vulnerable versions of Windows 10, Windows Server 2016, and Windows Server 2019 are at risk of experiencing complete console driver failures, which can render command line interfaces unusable and potentially affect automated processes that depend on console operations. Attackers could exploit this vulnerability to create persistent denial of service conditions against targeted systems, particularly in enterprise environments where console-based administrative tasks are common. The vulnerability also presents risks for privilege escalation scenarios since console driver access can sometimes be leveraged to gain deeper system access, making this issue particularly dangerous in multi-user or server environments.
Mitigation strategies for CVE-2021-28443 should prioritize immediate deployment of Microsoft security updates and patches released through Windows Update channels. Organizations should implement comprehensive monitoring of console driver behavior and system stability metrics to detect potential exploitation attempts. Network segmentation and access controls should be strengthened to limit potential attack vectors, particularly in environments where console-based applications are frequently used. System administrators should also consider implementing Application Control policies to restrict execution of potentially malicious console input sequences and establish baseline system behavior monitoring to detect anomalous console driver activity. The vulnerability aligns with ATT&CK technique T1489 which covers denial of service attacks, and may also map to T1059 for command and scripting interpreter usage patterns that could be exploited to trigger the vulnerability. Regular security assessments and vulnerability scanning should include verification of console driver integrity to ensure patched systems remain secure against potential variant exploits or related vulnerabilities.