CVE-2017-11056 in Android
Summary
by MITRE
In Android for MSM, Firefox OS for MSM, QRD Android, with all Android releases from CAF using the Linux kernel, while doing sha and cipher operations, a userspace buffer is directly accessed in kernel space potentially leading to a page fault.
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Analysis
by VulDB Data Team • 01/16/2021
The vulnerability identified as CVE-2017-11056 represents a critical kernel-space memory access flaw affecting multiple Android variants and Firefox OS implementations. This issue manifests within the Linux kernel subsystems used by Qualcomm Android Framework and related platforms, where userspace buffers are directly accessed from kernel space during cryptographic operations including SHA and cipher processing. The fundamental technical flaw occurs when the kernel attempts to reference user-provided buffer addresses without proper validation or sanitization, creating an exploitable condition that can be leveraged by malicious actors.
The operational impact of this vulnerability extends beyond simple memory corruption, as it creates a potential pathway for privilege escalation and system compromise. When cryptographic operations are performed, the kernel directly accesses user-space memory regions that may contain malformed or malicious data, leading to potential page fault conditions that can be exploited to gain unauthorized system access. This flaw aligns with CWE-125, which describes out-of-bounds read vulnerabilities, and represents a classic example of improper input validation in kernel space. The vulnerability is particularly concerning because it affects multiple platform variants including Android for MSM, Firefox OS for MSM, and QRD Android, indicating a widespread exposure across Qualcomm-based devices.
Attackers can exploit this vulnerability by crafting malicious inputs that, when processed through cryptographic functions, cause the kernel to access invalid memory addresses, potentially leading to denial of service conditions or more severe exploitation scenarios. The ATT&CK framework categorizes this as a privilege escalation technique through kernel vulnerabilities, where adversaries leverage kernel memory management flaws to execute code with elevated privileges. The vulnerability demonstrates a critical failure in kernel memory protection mechanisms, specifically in how kernel space handles user-provided data during cryptographic operations, making it a prime target for sophisticated exploitation campaigns targeting mobile platforms.
Mitigation strategies should focus on implementing proper kernel memory validation procedures and ensuring that all user-space buffer accesses are properly sanitized before kernel processing. System administrators should prioritize updating affected platforms to versions containing kernel patches that address the direct userspace buffer access issue. The fix typically involves implementing proper bounds checking and memory validation routines within the cryptographic subsystems, ensuring that kernel space operations cannot directly reference unvalidated user-provided memory addresses. Additionally, enabling kernel security features such as stack canaries and address space layout randomization can provide additional protection layers against exploitation attempts targeting this vulnerability.