CVE-2019-13377 in hostapd
Summary
by MITRE
The implementations of SAE and EAP-pwd in hostapd and wpa_supplicant 2.x through 2.8 are vulnerable to side-channel attacks as a result of observable timing differences and cache access patterns when Brainpool curves are used. An attacker may be able to gain leaked information from a side-channel attack that can be used for full password recovery.
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Analysis
by VulDB Data Team • 11/25/2023
The vulnerability identified as CVE-2019-13377 affects the secure authentication implementations within hostapd and wpa_supplicant versions 2.x through 2.8, specifically targeting the Simultaneous Authentication of Equals and EAP-pwd protocols. This security flaw resides in the cryptographic operations performed during the authentication process, where the implementation does not properly abstract the underlying mathematical computations to prevent timing and cache-based side-channel leakage. The vulnerability becomes particularly pronounced when Brainpool elliptic curve cryptography is utilized, as the specific mathematical operations involved in these curves create observable patterns that can be exploited by attackers.
The technical flaw stems from the implementation's failure to provide constant-time execution of cryptographic operations, particularly during the elliptic curve point multiplication processes required for SAE and EAP-pwd authentication. When Brainpool curves are employed, the mathematical operations exhibit measurable timing variations and cache access patterns that correlate with the secret password bits being processed. This timing differential allows an attacker to perform side-channel analysis and recover the password through statistical correlation of the observed execution patterns. The vulnerability operates under the principle that the time required to perform cryptographic operations varies based on the input data, creating information leakage that can be exploited through repeated measurements.
The operational impact of this vulnerability is severe as it enables attackers to perform offline password recovery attacks against wireless networks secured with SAE or EAP-pwd protocols. The side-channel attack can be conducted from a relatively close proximity to the target system, potentially from within the same network segment, making it a practical threat to wireless security deployments. Attackers can leverage this vulnerability to compromise enterprise wireless networks, personal Wi-Fi networks, and any system relying on these authentication protocols, potentially gaining unauthorized access to sensitive corporate or personal data. The vulnerability affects both the access point implementation in hostapd and the client implementation in wpa_supplicant, creating a comprehensive attack surface.
Mitigation strategies for this vulnerability require immediate patching of affected hostapd and wpa_supplicant installations to versions that implement constant-time cryptographic operations and eliminate the timing and cache access patterns that reveal password information. Organizations should also consider implementing additional network segmentation and access controls to limit the impact of potential compromise. The implementation should be reviewed against CWE-388 guidelines for side-channel attack prevention, ensuring that cryptographic operations are designed to be independent of secret data. Network administrators should also consider disabling Brainpool curve usage in favor of more resistant elliptic curve implementations until proper constant-time cryptographic libraries are deployed. The ATT&CK framework categorizes this vulnerability under credential access techniques, specifically targeting the exploitation of weak cryptographic implementations to recover authentication credentials.