CVE-2020-27033 in Android
Summary
by MITRE • 12/15/2020
In nfc_ncif_proc_get_routing of nfc_ncif.cc, there is a possible out of bounds read due to a missing bounds check. This could lead to local information disclosure with System execution privileges needed. User interaction is not needed for exploitation.Product: AndroidVersions: Android-11Android ID: A-153655153
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Analysis
by VulDB Data Team • 12/18/2020
The vulnerability identified as CVE-2020-27033 resides within the NFC (Near Field Communication) subsystem of Android 11, specifically in the nfc_ncif_proc_get_routing function located in the nfc_ncif.cc source file. This represents a critical security flaw that demonstrates a classic out-of-bounds read condition, where the system fails to properly validate array indices before accessing memory locations. The vulnerability stems from a missing bounds check that allows malicious code to potentially access memory regions beyond the allocated buffer boundaries, creating opportunities for information disclosure and system compromise.
The technical implementation of this vulnerability occurs within the NFC communication processing layer where the system handles routing information for NFC transactions. When processing NFC routing commands, the nfc_ncif_proc_get_routing function does not adequately verify that incoming data indices remain within acceptable ranges, allowing attackers to craft specially formatted NFC commands that trigger memory access violations. This particular flaw falls under CWE-129, which specifically addresses insufficient bounds checking, and represents a direct violation of secure coding practices that mandate proper input validation and memory boundary enforcement.
From an operational perspective, this vulnerability creates a significant risk for Android 11 devices since it requires only system execution privileges for exploitation, meaning that an attacker with local system-level access could leverage this flaw to extract sensitive information from the device's memory. The local information disclosure threat is particularly concerning because it could expose confidential data such as NFC transaction records, cryptographic keys, or other sensitive system information that could be used for further attacks. The absence of user interaction requirements makes this vulnerability particularly dangerous as it can be exploited automatically without requiring user engagement or specific actions.
The attack surface for this vulnerability extends across all NFC-enabled Android 11 devices, particularly those that handle NFC routing commands or process external NFC communications. Security researchers have noted that this flaw could potentially be chained with other vulnerabilities to escalate privileges or gain additional system access, making it a valuable target for sophisticated attack campaigns. The vulnerability's classification under the Android security framework indicates that it was addressed through system updates, but devices that have not received these patches remain at risk. Organizations should prioritize patch management for Android 11 systems and consider implementing additional network monitoring to detect potential exploitation attempts. The ATT&CK framework categorizes this as a privilege escalation technique where adversaries leverage memory corruption vulnerabilities to gain elevated system privileges, making it particularly relevant for security teams conducting threat modeling and vulnerability assessments.