CVE-2022-20198 in Android
Summary
by MITRE • 06/15/2022
In llcp_dlc_proc_connect_pdu of llcp_dlc.cc, there is a possible out of bounds read due to a missing bounds check. This could lead to local information disclosure from the NFC stack with System execution privileges needed. User interaction is not needed for exploitation.Product: AndroidVersions: Android-12LAndroid ID: A-221851879
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Analysis
by VulDB Data Team • 06/15/2022
The vulnerability identified as CVE-2022-20198 resides within the NFC (Near Field Communication) stack implementation of Android 12L systems, specifically within the llcp_dlc_proc_connect_pdu function located in the llcp_dlc.cc source file. This represents a critical security flaw that demonstrates poor input validation practices in the NFC protocol handling layer. The vulnerability manifests as a missing bounds check during processing of connection protocol data units, creating an opportunity for memory access violations that can be exploited by malicious actors with system-level privileges.
The technical flaw constitutes an out-of-bounds read condition that occurs when the NFC stack processes connection requests without properly validating the length or boundaries of incoming data packets. This missing validation allows an attacker to craft specially formatted NFC connection PDUs that can cause the system to read memory locations beyond the intended buffer boundaries. The vulnerability specifically impacts the Logical Link Control Protocol (LLCP) layer which governs communication between NFC devices, making it a core component of the NFC subsystem's security posture. According to CWE-129, this represents an implementation flaw where insufficient input length validation leads to memory access violations that can be leveraged for information disclosure.
The operational impact of this vulnerability is significant as it enables local information disclosure from the NFC stack when exploited by an attacker with system execution privileges. While the vulnerability requires system-level access for exploitation, this represents a serious concern given that NFC functionality is integral to Android's security model and device operations. The information disclosure could potentially expose sensitive NFC stack memory contents, including cryptographic keys, session data, or other confidential information that may be stored in memory during NFC transactions. This type of vulnerability aligns with ATT&CK technique T1005 where adversaries can access data from local systems through memory access vulnerabilities.
The exploitation of this vulnerability requires an attacker to have system execution privileges, which typically means they already possess elevated access to the device. However, the fact that this vulnerability exists within the NFC stack suggests potential for escalation or lateral movement within the device's security boundaries. The Android security model relies heavily on proper validation of all system components, and this flaw demonstrates the importance of input validation in security-critical subsystems. The vulnerability's classification as a local information disclosure indicates that while it may not be directly exploitable from remote locations, it represents a serious weakness that could be combined with other vulnerabilities to create more severe attack vectors.
Mitigation strategies for CVE-2022-20198 should focus on implementing proper bounds checking within the NFC stack's LLCP processing functions. The fix should involve adding comprehensive input validation to ensure that all connection PDU data is properly bounded before processing, preventing the out-of-bounds read condition. Android security patches should address this by incorporating defensive programming practices that validate data lengths and buffer boundaries. Organizations should ensure that affected Android 12L devices receive timely security updates and that NFC functionality is properly monitored for unusual behavior patterns. The vulnerability highlights the importance of regular security audits of core system components and the necessity of robust input validation mechanisms throughout the Android security architecture.