CVE-2017-11059 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, setting the HMAC key by different threads during SHA operations may potentially lead to a buffer overflow.
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Analysis
by VulDB Data Team • 01/16/2021
This vulnerability exists within the Linux kernel implementation used in various Android and Firefox OS devices, specifically affecting systems built on Qualcomm Snapdragon platforms. The flaw manifests during cryptographic operations involving HMAC (Hash-based Message Authentication Code) calculations where multiple threads attempt to set or modify the HMAC key simultaneously while SHA (Secure Hash Algorithm) operations are in progress. The issue stems from inadequate thread synchronization mechanisms within the kernel's cryptographic subsystem, creating a race condition scenario where concurrent access to shared cryptographic resources results in improper memory management.
The technical implementation involves the kernel's handling of cryptographic contexts and key storage during HMAC computations. When multiple threads invoke HMAC operations concurrently, the system fails to properly serialize access to the underlying key buffers, potentially allowing one thread to overwrite or corrupt data structures that another thread is actively using. This race condition specifically impacts the SHA hashing operations that are fundamental to HMAC functionality, creating a scenario where buffer boundaries may be exceeded during key setting operations. The vulnerability is classified as a buffer overflow due to the potential for unauthorized memory access and data corruption that can occur when thread-safe mechanisms are bypassed during cryptographic processing.
The operational impact of this vulnerability extends beyond simple data corruption, as it can potentially enable privilege escalation attacks and compromise the integrity of cryptographic operations. An attacker exploiting this vulnerability could manipulate the HMAC key storage mechanisms to inject malicious data or cause system instability, potentially leading to complete system compromise. The vulnerability affects all Android releases from the Code Aurora Forum (CAF) that utilize the Linux kernel, representing a significant attack surface across multiple device manufacturers and platform versions. This weakness directly violates the principle of secure concurrent programming and undermines the fundamental security guarantees provided by cryptographic operations.
Mitigation strategies must address both the immediate kernel-level issues and broader system security posture. System administrators should implement kernel updates that include proper mutex locking mechanisms for HMAC key operations and ensure that all cryptographic contexts are properly synchronized across threads. The fix typically involves adding appropriate locking primitives around key setting operations during SHA processing to prevent concurrent access. Additionally, organizations should conduct thorough security assessments of their device firmware and ensure that all devices running affected kernel versions receive timely patches. This vulnerability aligns with CWE-362 (Concurrent Execution using Shared Resource with Unprotected Shared Resource) and could be leveraged by attackers following ATT&CK techniques related to privilege escalation and credential access. The remediation process requires careful consideration of performance implications while maintaining cryptographic security guarantees.