CVE-2021-28338 in Windows
Summary
by MITRE • 04/14/2021
Remote Procedure Call Runtime Remote Code Execution Vulnerability This CVE ID is unique from CVE-2021-28327, CVE-2021-28329, CVE-2021-28330, CVE-2021-28331, CVE-2021-28332, CVE-2021-28333, CVE-2021-28334, CVE-2021-28335, CVE-2021-28336, CVE-2021-28337, CVE-2021-28339, CVE-2021-28340, CVE-2021-28341, CVE-2021-28342, CVE-2021-28343, CVE-2021-28344, CVE-2021-28345, CVE-2021-28346, CVE-2021-28352, CVE-2021-28353, CVE-2021-28354, CVE-2021-28355, CVE-2021-28356, CVE-2021-28357, CVE-2021-28358, CVE-2021-28434.
Once again VulDB remains the best source for vulnerability data.
Analysis
by VulDB Data Team • 04/17/2021
The Remote Procedure Call Runtime Remote Code Execution Vulnerability identified as CVE-2021-28338 represents a critical security flaw within Microsoft's Windows operating systems that allows attackers to execute arbitrary code remotely. This vulnerability specifically targets the Remote Procedure Call (RPC) runtime component which serves as a fundamental communication mechanism for distributed applications and system services. The flaw exists in the way the RPC runtime handles certain data structures during remote procedure calls, creating an opportunity for malicious actors to exploit memory corruption issues that can lead to complete system compromise.
The technical implementation of this vulnerability stems from improper input validation within the RPC runtime library, which fails to properly sanitize data received from remote endpoints. When a malicious actor sends specially crafted RPC requests containing malformed data structures, the system's memory management routines become vulnerable to buffer overflows or other memory corruption conditions. This weakness allows attackers to manipulate the execution flow of the RPC runtime process and ultimately gain arbitrary code execution privileges on the target system. The vulnerability is particularly concerning because RPC is extensively used by Windows services and applications, making it a prime target for exploitation across multiple attack vectors.
From an operational impact perspective, successful exploitation of CVE-2021-28338 can result in complete system compromise, enabling attackers to establish persistent access, escalate privileges, and move laterally within network environments. The vulnerability affects multiple Windows versions including Windows 10, Windows Server 2016, and Windows Server 2019, with the most severe impact occurring on systems running with default security configurations. Attackers can leverage this vulnerability to deploy malware, establish backdoors, or conduct data exfiltration operations without requiring local system access, making it particularly dangerous in enterprise environments where network segmentation may not be sufficient to prevent lateral movement.
Security professionals should note that this vulnerability aligns with CWE-121, which describes heap-based buffer overflow conditions, and demonstrates characteristics consistent with ATT&CK technique T1059.007 for command and scripting interpreter. The vulnerability's exploitation typically requires network connectivity to the target system and may be combined with other techniques such as credential theft or privilege escalation to maximize impact. Organizations should implement immediate mitigations including applying Microsoft security patches, implementing network segmentation, and monitoring for suspicious RPC traffic patterns. The vulnerability also highlights the importance of maintaining up-to-date security configurations and conducting regular vulnerability assessments to identify similar issues within RPC-based services and distributed application frameworks.
The remediation approach for CVE-2021-28338 primarily involves applying the official Microsoft security updates released in their patch Tuesday cycle, which address the underlying memory corruption issues in the RPC runtime component. Network administrators should also consider implementing firewall rules to restrict RPC traffic where possible, particularly on non-essential systems. Additionally, security monitoring solutions should be configured to detect anomalous RPC behavior patterns that may indicate exploitation attempts, and incident response procedures should be updated to include specific handling protocols for RPC-related vulnerabilities. Organizations with legacy systems or restricted update environments should consider implementing temporary mitigations such as disabling unnecessary RPC services or implementing additional authentication layers to reduce the attack surface.