CVE-2017-18126 in Android
Summary
by MITRE
In Android before security patch level 2018-04-05 on Qualcomm Snapdragon Mobile and Snapdragon Wear MDM9206, MDM9607, MDM9640, MDM9650, QCA6174A, QCA6574, QCA6574AU, QCA6584, QCA6584AU, QCA9377, QCA9379, SD 210/SD 212/SD 205, SD 410/12, SD 425, SD 427, SD 430, SD 435, SD 450, SD 615/16/SD 415, SD 625, SD 650/52, SD 808, SD 810, SD 820, SD 835, SD 845, SDM630, SDM636, SDM660, Snapdragon_High_Med_2016, the original mac spoofing feature does not use the following in probe request frames: (a) randomized sequence numbers and (b) randomized source address for cfg80211 scan, vendor scan and pno scan which may affect user privacy.
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Analysis
by VulDB Data Team • 01/24/2020
The vulnerability CVE-2017-18126 represents a significant privacy flaw in Qualcomm-based Android devices that affects numerous Snapdragon chipsets including MDM9206, MDM9607, MDM9640, MDM9650, and various QCA and SD series processors. This issue resides in the original mac spoofing implementation within the wireless networking stack, specifically within the cfg80211 subsystem that handles 802.11 scanning operations. The flaw manifests in probe request frames sent during network discovery processes, where the system fails to properly randomize critical identifiers that could be used to track user movements and device activities across networks.
The technical root cause of this vulnerability stems from improper implementation of privacy-preserving mechanisms within the wireless scanning framework. When devices perform background scans for available networks, they construct probe request frames containing source MAC addresses and sequence numbers that remain static or predictably generated rather than being randomized. This behavior violates fundamental privacy principles and creates persistent identifiers that can be exploited by malicious actors or surveillance systems to correlate device activities over time and location. The vulnerability specifically impacts three distinct scanning modes: standard cfg80211 scan, vendor-specific scan operations, and predictive network optimization (pno) scans, each representing different contexts where wireless devices actively seek network information.
From an operational perspective, this vulnerability creates substantial privacy risks for users of affected devices, as it enables passive tracking of device movements and network usage patterns without user knowledge or consent. The lack of sequence number randomization and source address randomization means that network observers can potentially identify specific devices across different networks and time periods, undermining the intended privacy protections of MAC address randomization features. This weakness particularly affects users in environments where wireless monitoring is prevalent, such as public spaces, corporate networks, or areas with malicious actors who may be actively collecting wireless traffic data. The vulnerability's impact extends beyond simple location tracking to potentially enable more sophisticated profiling activities that could compromise user anonymity and behavioral privacy.
Organizations and device manufacturers should implement immediate mitigations including firmware updates that properly randomize sequence numbers and source addresses in probe request frames, ensuring compliance with established privacy standards. The vulnerability aligns with CWE-384, which addresses the use of predictable identifiers in security-sensitive contexts, and relates to ATT&CK technique T1566 for social engineering through wireless network monitoring. Users should ensure their devices receive security patches promptly, and network administrators should consider implementing additional monitoring controls to detect and respond to suspicious scanning activities. The remediation process must address all affected Snapdragon chipsets mentioned in the vulnerability description to ensure comprehensive protection against persistent tracking mechanisms that could be exploited for malicious purposes.