CVE-2023-21690 in Windows
Summary
by MITRE • 02/14/2023
Microsoft Protected Extensible Authentication Protocol (PEAP) Remote Code Execution Vulnerability
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Analysis
by VulDB Data Team • 03/15/2023
The CVE-2023-21690 vulnerability represents a critical remote code execution flaw within Microsoft's Protected Extensible Authentication Protocol implementation that affects enterprise network authentication systems. This vulnerability specifically targets the PEAP authentication mechanism used in Windows environments, where it allows unauthenticated attackers to execute arbitrary code on affected systems. The flaw exists in the way PEAP processes certain authentication messages, creating a pathway for malicious actors to bypass normal authentication procedures and gain system-level access. The vulnerability impacts multiple Windows operating systems including Windows 10, Windows 11, and various server editions, making it particularly dangerous for enterprise environments that rely heavily on wireless and wired network authentication. Security researchers identified this issue through careful analysis of the PEAP implementation within Microsoft's authentication stack, noting that the vulnerability stems from improper input validation during the authentication handshake process.
The technical exploitation of CVE-2023-21690 occurs when an attacker crafts malicious PEAP authentication messages that trigger a buffer overflow or memory corruption condition within the affected authentication components. This flaw aligns with CWE-121, which describes stack-based buffer overflow conditions, and CWE-787, which covers out-of-bounds write operations. The vulnerability can be leveraged through wireless networks where PEAP is configured as an authentication method, particularly in enterprise environments using Cisco wireless access points or Microsoft's own wireless infrastructure. Attackers can exploit this weakness without requiring valid credentials, making it especially dangerous as it allows for unauthorized access to network resources. The vulnerability's impact extends beyond simple authentication bypass, as successful exploitation can lead to full system compromise and lateral movement within the network. Network administrators should note that the attack vector typically involves intercepting or manipulating authentication traffic, making it particularly challenging to detect through conventional network monitoring approaches.
Organizations affected by CVE-2023-21690 face significant operational risks including potential data breaches, unauthorized network access, and system compromise that could affect critical business operations. The vulnerability's ability to execute code remotely without authentication makes it particularly attractive to advanced persistent threat actors who seek to establish persistent access to enterprise networks. From an ATT&CK framework perspective, this vulnerability maps to techniques including T1078 Valid Accounts for initial access, T1566 Phishing for Initial Access when combined with social engineering, and T1059 Command and Scripting Interpreter for executing malicious code. The exploitation of this vulnerability can lead to privilege escalation and lateral movement throughout the network, potentially compromising sensitive data and systems. Organizations should consider the broader implications of this vulnerability on their security posture, particularly in environments where wireless networks are extensively used for employee access. The risk assessment should include evaluation of wireless infrastructure, authentication server configurations, and network segmentation practices that may be affected by this flaw.
Mitigation strategies for CVE-2023-21690 should prioritize immediate patch deployment through Microsoft's regular security updates, as the vendor has released patches specifically addressing this vulnerability. Organizations should also implement network segmentation to limit the potential impact of exploitation, particularly by isolating wireless networks from critical business systems. Network administrators should consider disabling PEAP authentication temporarily if immediate patching is not feasible, though this may impact legitimate user access. Additional defensive measures include enhanced network monitoring for unusual authentication patterns, implementation of intrusion detection systems that can identify exploitation attempts, and regular security assessments of wireless infrastructure. The vulnerability highlights the importance of maintaining current security patches and implementing robust network access controls. Security teams should also consider implementing multi-factor authentication mechanisms that provide additional protection layers beyond simple PEAP authentication, as well as regular vulnerability scanning to identify other potential weaknesses in the authentication infrastructure. Organizations should review their incident response procedures to ensure readiness for potential exploitation of this vulnerability, particularly in environments where wireless access is critical to business operations.