CVE-2015-9221 in Android
Summary
by MITRE
In Android before 2018-04-05 or earlier security patch level on Qualcomm Snapdragon Mobile SD 400, SD 800, and SD 810, lack of validation of pointers passed by secure apps could lead to an untrusted pointer dereference.
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Analysis
by VulDB Data Team • 01/27/2020
The vulnerability identified as CVE-2015-9221 represents a critical pointer validation flaw within the Qualcomm Snapdragon mobile chipsets affecting Android devices prior to the 2018-04-05 security patch level. This issue specifically impacts the SD 400, SD 800, and SD 810 processor series, which were widely deployed in numerous flagship and mid-range smartphones during the 2015-2017 period. The vulnerability stems from insufficient validation mechanisms within the secure execution environment where trusted applications pass pointers to kernel-level components without proper verification of pointer legitimacy. This architectural weakness creates a pathway for malicious actors to manipulate memory references and potentially execute arbitrary code with elevated privileges. The flaw operates at the intersection of hardware security and software validation, where the secure world of the processor fails to properly authenticate the origins and validity of pointer references originating from secure applications. This vulnerability directly corresponds to CWE-476, which describes NULL pointer dereference conditions, and more specifically aligns with CWE-787, representing out-of-bounds write operations that can occur when pointer validation is inadequate. The operational impact extends beyond simple privilege escalation as it enables attackers to bypass the fundamental security boundaries between trusted and untrusted execution environments. When exploited, this vulnerability allows malicious actors to transition from a standard application context to a privileged kernel execution state, potentially compromising the entire device. The attack vector typically involves crafting malicious input that manipulates pointer values passed from secure applications to kernel components, leading to memory corruption and unauthorized code execution. This flaw particularly affects devices where Qualcomm's secure execution environment relies on implicit trust assumptions rather than explicit validation of all pointer references. The vulnerability has been classified under the MITRE ATT&CK framework as a privilege escalation technique, specifically leveraging the 'Exploitation for Privilege Escalation' tactic. Devices utilizing these vulnerable chipsets during the affected period were susceptible to complete compromise, as the flaw essentially allows attackers to subvert the processor's security model. The patch implementation required modifications to the secure world memory management subsystem to enforce proper pointer validation before any memory dereference operations occur. Organizations affected by this vulnerability needed to implement comprehensive device update strategies, as the fix required both kernel-level modifications and hardware-specific patches to address the root cause. The widespread deployment of these vulnerable chipsets across multiple Android manufacturers meant that a significant portion of the mobile device ecosystem was exposed to potential exploitation. Security researchers noted that the vulnerability's exploitation was particularly concerning due to its ability to bypass hardware-based security features designed to isolate secure and non-secure execution contexts. The remediation process involved updating the secure processing environment to enforce strict pointer validation protocols, ensuring that all memory references originating from secure applications are verified against legitimate memory regions before any dereference operations occur. This vulnerability highlighted the critical importance of comprehensive security validation at all levels of the execution stack, from application code to hardware-level memory management systems. The impact extends beyond immediate device compromise to include potential data exfiltration and persistent backdoor establishment, making it a particularly dangerous vulnerability in the mobile security landscape.