CVE-2019-9497 in hostapd
Summary
by MITRE
The implementations of EAP-PWD in hostapd EAP Server and wpa_supplicant EAP Peer do not validate the scalar and element values in EAP-pwd-Commit. This vulnerability may allow an attacker to complete EAP-PWD authentication without knowing the password. However, unless the crypto library does not implement additional checks for the EC point, the attacker will not be able to derive the session key or complete the key exchange. Both hostapd with SAE support and wpa_supplicant with SAE support prior to and including version 2.4 are affected. Both hostapd with EAP-pwd support and wpa_supplicant with EAP-pwd support prior to and including version 2.7 are affected.
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Analysis
by VulDB Data Team • 08/29/2023
The vulnerability described in CVE-2019-9497 represents a critical flaw in the implementation of EAP-PWD (Extensible Authentication Protocol - Password) within widely used wireless authentication software components. This weakness specifically affects hostapd and wpa_supplicant implementations that support EAP-PWD authentication protocols, creating a potential pathway for unauthorized network access. The vulnerability stems from inadequate validation of cryptographic parameters during the EAP-pwd-Commit phase of the authentication process, which is a fundamental step in establishing secure wireless connections. The flaw exists in both the EAP Server implementation within hostapd and the EAP Peer implementation within wpa_supplicant, making it particularly concerning given the widespread deployment of these software components in enterprise and consumer wireless networks.
The technical nature of this vulnerability lies in the insufficient validation of scalar and element values within the EAP-pwd-Commit message structure. According to CWE-310, this represents a weakness in cryptographic implementation where proper input validation is missing, allowing malformed parameters to be processed without adequate security checks. The vulnerability specifically targets the elliptic curve cryptography components used in EAP-PWD, where attackers can manipulate the cryptographic parameters to bypass the normal authentication flow. While the authentication process may appear to complete successfully from the attacker's perspective, the fundamental cryptographic validation checks that should prevent such manipulation are absent. This creates a scenario where an attacker can potentially establish a valid authentication session without possessing the legitimate password, though the attack vector is not without its limitations.
The operational impact of this vulnerability extends beyond simple credential theft, as it fundamentally undermines the security assumptions of the EAP-PWD protocol. In the context of wireless network security, this weakness could enable attackers to gain unauthorized access to protected networks, potentially leading to data breaches, man-in-the-middle attacks, and lateral movement within network environments. The vulnerability affects versions of hostapd and wpa_supplicant that implement SAE (Simultaneous Authentication of Equals) support up to version 2.4 and EAP-PWD support up to version 2.7, indicating that a significant portion of wireless infrastructure software was potentially exposed. From an ATT&CK framework perspective, this vulnerability maps to T1566 (Phishing) and T1562 (Impairing Defenses) as it enables unauthorized access through manipulated authentication flows and weakens the cryptographic defenses of wireless networks.
Mitigation strategies for CVE-2019-9497 require immediate software updates to versions that properly implement cryptographic parameter validation for EAP-PWD. Organizations should prioritize patching both hostapd and wpa_supplicant installations, particularly in environments where wireless security is paramount. Network administrators should also consider implementing additional monitoring for unusual authentication patterns that might indicate exploitation attempts. The vulnerability highlights the importance of proper cryptographic implementation practices and adherence to standards such as NIST SP 800-56A for elliptic curve cryptography. Security teams should conduct comprehensive audits of wireless infrastructure to identify systems running vulnerable versions and ensure that all cryptographic parameters are properly validated before being accepted into the authentication process. The fix addresses the root cause by implementing proper validation checks that ensure scalar and element values fall within acceptable ranges for the elliptic curve operations, preventing attackers from manipulating the cryptographic parameters to bypass authentication requirements.