CVE-2016-2432 in Android
Summary
by MITRE
The Qualcomm TrustZone component in Android before 2016-05-01 on Nexus 6 and Android One devices allows attackers to gain privileges via a crafted application, aka internal bug 25913059.
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Analysis
by VulDB Data Team • 11/07/2018
The vulnerability identified as CVE-2016-2432 represents a critical privilege escalation flaw within the Qualcomm TrustZone security component that affected Android devices prior to the 2016-05-01 security patch release. This vulnerability specifically impacted Nexus 6 and Android One devices, creating a significant security risk that allowed malicious actors to bypass the hardware-based security protections typically provided by the TrustZone architecture. The flaw was classified as an internal bug with the identifier 25913059, indicating its origins within Qualcomm's proprietary security implementation rather than a standard open-source vulnerability.
The technical nature of this vulnerability stems from improper access control mechanisms within the TrustZone component that governs secure execution environments on Android devices. The TrustZone architecture is designed to provide a hardware-level secure processing environment that isolates sensitive operations from the main operating system, creating a trusted execution environment for functions such as fingerprint authentication, secure boot processes, and cryptographic operations. However, the flaw in the Qualcomm implementation allowed a crafted malicious application to exploit a weakness in the privilege separation mechanisms, potentially enabling attackers to escalate their privileges from regular application level to system-level access within the secure domain.
The operational impact of this vulnerability extends beyond simple privilege escalation, as it fundamentally undermines the security model that TrustZone was designed to protect. When exploited, the vulnerability could enable attackers to gain unauthorized access to secure elements of the device, potentially compromising biometric authentication data, encryption keys, and other sensitive security information stored within the TrustZone environment. This represents a direct violation of the principle of least privilege and could allow adversaries to perform actions such as extracting secure keys, modifying secure boot processes, or bypassing authentication mechanisms that rely on hardware security features. The vulnerability's classification under CWE-284 (Improper Access Control) highlights the fundamental flaw in authorization mechanisms that permitted unauthorized privilege elevation.
Attackers could leverage this vulnerability through a malicious application that would need to be installed on the target device, potentially via social engineering, phishing campaigns, or other delivery methods. The exploitation process would involve crafting specific code that could trigger the privilege escalation within the TrustZone environment, bypassing the normal security boundaries that separate trusted and untrusted code execution. This attack vector aligns with ATT&CK technique T1068 (Local Port Forwarding) and T1548.001 (Abuse Elevation Control Mechanism) as it exploits weaknesses in system privilege control mechanisms. The vulnerability's impact was particularly severe because it affected devices that were widely distributed and used in enterprise environments, where the compromise of a single device could potentially lead to broader network infiltration.
Mitigation strategies for this vulnerability required immediate deployment of the security patch released by Google on May 1, 2016, which addressed the TrustZone privilege escalation flaw in Qualcomm's implementation. Device manufacturers and carriers needed to ensure rapid distribution of the update to affected Nexus 6 and Android One devices. Additionally, security professionals recommended implementing application whitelisting policies and monitoring for suspicious privilege escalation attempts on affected devices. The vulnerability highlighted the importance of proper security testing for hardware security modules and underscored the need for continuous security validation of trusted execution environments. Organizations should have implemented network monitoring to detect potential exploitation attempts and established incident response procedures for handling compromised devices within their environments. The resolution of this vulnerability demonstrated the critical relationship between software updates and hardware security components, emphasizing that security patches must address both software and hardware-level vulnerabilities to maintain comprehensive protection.