CVE-2021-28182 in BMC
Summary
by MITRE • 04/06/2021
The Web Service configuration function in ASUS BMC’s firmware Web management page does not verify the string length entered by users, resulting in a Buffer overflow vulnerability. As obtaining the privileged permission, remote attackers use the leakage to abnormally terminate the Web service.
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Analysis
by VulDB Data Team • 04/10/2021
The vulnerability identified as CVE-2021-28182 resides within the Web Service configuration functionality of ASUS Baseboard Management Controller (BMC) firmware, specifically affecting the web management interface. This issue represents a classic buffer overflow vulnerability that occurs when the system fails to properly validate input string lengths during user data entry. The flaw manifests in the web management page's handling of user-provided data, where insufficient bounds checking allows malicious inputs to exceed allocated buffer space. The vulnerability is particularly concerning as it affects the BMC firmware which serves as a critical management interface for networked devices, providing administrators with remote access capabilities for system monitoring and configuration.
The technical implementation of this vulnerability stems from inadequate input validation mechanisms within the web service configuration component. When users enter data through the web interface, the system does not perform proper string length verification before processing the input, creating an opportunity for buffer overflow conditions. This type of flaw falls under CWE-121, which specifically addresses stack-based buffer overflow conditions, and represents a common weakness in software development practices where input sanitization is insufficient. The buffer overflow occurs in the web service configuration function, where user-supplied data is directly copied into fixed-length buffers without adequate bounds checking, allowing attackers to overwrite adjacent memory locations.
The operational impact of CVE-2021-28182 extends beyond simple service disruption to potentially enable privilege escalation and remote code execution. While the description indicates that remote attackers can use this vulnerability to abnormally terminate the web service, the broader implications suggest that an attacker with sufficient privileges could exploit this weakness to gain deeper system access. The BMC environment typically operates with elevated privileges, making successful exploitation potentially catastrophic for network security. The vulnerability's remote attack surface means that malicious actors can leverage this flaw from external networks without requiring physical access to the target systems, aligning with ATT&CK technique T1059 for command and script interpreter usage and T1071 for application layer protocol communication.
Mitigation strategies for this vulnerability should prioritize immediate firmware updates from ASUS to address the buffer overflow condition. Organizations should also implement network segmentation to limit access to BMC management interfaces, restricting access to trusted network segments only. Additional protective measures include implementing strict input validation on web application firewalls and monitoring for unusual traffic patterns that might indicate exploitation attempts. The vulnerability highlights the importance of proper software development practices including input validation, bounds checking, and regular security assessments. Security teams should also conduct vulnerability scans to identify affected devices and ensure that all BMC firmware versions are current with the latest security patches. Network administrators should consider disabling unnecessary web management services when not actively required, reducing the attack surface for potential exploitation of this and similar vulnerabilities.