CVE-2016-10743 in Hostapd
Summary
by MITRE
hostapd before 2.6 does not prevent use of the low-quality PRNG that is reached by an os_random() function call.
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Analysis
by VulDB Data Team • 08/04/2023
The vulnerability identified as CVE-2016-10743 affects hostapd versions prior to 2.6, representing a significant weakness in the wireless access point daemon's cryptographic randomness implementation. This flaw resides in the os_random() function call which is responsible for generating cryptographically secure random numbers required for various security operations within the wireless authentication process. The issue stems from the use of a low-quality pseudo-random number generator that fails to provide adequate entropy for cryptographic operations, creating predictable sequences that can be exploited by attackers.
The technical implementation flaw occurs when hostapd invokes the os_random() function to generate random values for critical security parameters such as session keys, nonces, and other cryptographic elements used during wireless authentication. This weakness directly violates the fundamental principles of cryptographic security where random number generation must meet strict entropy requirements to prevent attackers from predicting future values or reconstructing past cryptographic operations. The vulnerability is classified under CWE-330, which specifically addresses insufficient entropy in random number generation, making it a direct violation of cryptographic best practices.
The operational impact of this vulnerability extends beyond simple predictability issues, as it fundamentally undermines the security of wireless networks managed by affected hostapd versions. Attackers who can predict the random values generated by the flawed PRNG can potentially impersonate legitimate access points, intercept wireless communications, or perform man-in-the-middle attacks against wireless clients. The vulnerability affects wireless authentication protocols including WPA and WPA2, where predictable random numbers can lead to session key recovery attacks and complete compromise of wireless network security. This weakness aligns with ATT&CK technique T1046, which involves network service scanning, as attackers may leverage predictable randomness to identify and exploit vulnerable wireless networks more effectively.
Mitigation strategies for this vulnerability require immediate upgrade to hostapd version 2.6 or later, which includes proper implementation of cryptographic random number generation. Organizations should also implement comprehensive network monitoring to detect unusual authentication patterns that might indicate exploitation attempts. Additional security measures include regular security audits of wireless infrastructure, implementation of robust key management practices, and consideration of alternative wireless security protocols that are less susceptible to random number generation weaknesses. The fix addresses the underlying cryptographic implementation by ensuring that the os_random() function properly interfaces with high-quality entropy sources, thereby restoring the cryptographic integrity of wireless authentication processes.