CVE-2017-15817 in Android
Summary
by MITRE
In all Qualcomm products with Android releases from CAF using the Linux kernel, when an access point sends a challenge text greater than 128 bytes, the host driver is unable to validate this potentially leading to authentication failure.
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Analysis
by VulDB Data Team • 01/08/2020
This vulnerability resides in Qualcomm's implementation of wireless network authentication within Android devices running Linux kernel versions from the Common Android Framework. The flaw manifests when a wireless access point transmits a challenge text exceeding 128 bytes in length during the authentication process. The host driver fails to properly validate such oversized challenge texts, creating a potential security gap that could be exploited by malicious actors. This issue affects all Qualcomm products utilizing Android releases from the Common Android Framework and operates at the kernel level where wireless network protocols are handled. The vulnerability stems from inadequate input validation mechanisms within the wireless driver implementation, specifically in how it processes authentication challenge responses from access points.
The technical root cause of CVE-2017-15817 lies in the insufficient boundary checking within the wireless authentication subsystem. When an access point sends a challenge text that surpasses the 128-byte threshold, the host driver's validation logic cannot properly handle the oversized data structure, leading to potential authentication failures or unexpected behavior. This represents a classic buffer overflow vulnerability pattern where the system does not properly validate input lengths before processing them. The vulnerability operates at the network protocol level, specifically affecting the 802.11 wireless authentication mechanisms that rely on challenge-response authentication methods. This flaw directly relates to CWE-122, which describes improper restriction of operations within a recognized security boundary, and CWE-125, which covers out-of-bounds read conditions.
The operational impact of this vulnerability extends beyond simple authentication failures to potentially enable various attack vectors. An attacker positioned within wireless range could exploit this weakness by crafting malicious challenge texts that exceed the 128-byte limit, potentially causing denial of service conditions or bypassing certain authentication mechanisms. This vulnerability could allow unauthorized network access if the authentication failure results in fallback mechanisms that are less secure. The issue affects the integrity of wireless network connections and could compromise the confidentiality of data transmitted over affected networks. From an attacker perspective, this represents a low-effort method to disrupt wireless communications or potentially gain unauthorized access to networks, particularly in environments where wireless authentication is critical for security. The vulnerability operates under ATT&CK technique T1566, which involves phishing attacks through wireless networks, and T1075, which covers use of valid accounts through wireless access points.
Mitigation strategies for this vulnerability require both immediate and long-term approaches to address the underlying driver implementation issues. Qualcomm should implement proper input validation mechanisms within the wireless driver to enforce strict bounds checking on challenge text lengths, ensuring that all authentication challenge responses are properly validated regardless of their size. System administrators and device manufacturers should update to patched kernel versions that address this specific validation flaw, while network administrators should monitor for unusual authentication patterns that might indicate exploitation attempts. The fix should include implementing proper memory management and buffer allocation techniques to handle oversized challenge texts gracefully without causing authentication failures. Additionally, organizations should consider implementing network monitoring solutions that can detect and alert on unusual challenge text lengths being transmitted through wireless networks, as this could serve as an indicator of exploitation attempts. Regular security audits of wireless network implementations should include verification that authentication mechanisms properly handle edge cases and oversized inputs to prevent similar vulnerabilities from emerging in the future.