CVE-2017-15834 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, race condition in diag_dbgfs_read_dcistats(), while accessing diag_dbgfs_dci_data_index, causes potential heap overflow.
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Analysis
by VulDB Data Team • 02/22/2023
The vulnerability identified as CVE-2017-15834 represents a critical race condition flaw within the Linux kernel implementation used across various Android platforms including MSM, Firefox OS, and QRD Android releases. This issue manifests in the diag_dbgfs_read_dcistats() function which handles diagnostic data access through debug filesystem interfaces. The core problem emerges when multiple threads simultaneously access the diag_dbgfs_dci_data_index variable without proper synchronization mechanisms, creating a scenario where concurrent read and write operations can corrupt memory structures.
The technical exploitation of this vulnerability leverages a classic race condition pattern where the timing of concurrent operations creates unpredictable behavior in memory management. When the diag_dbgfs_read_dcistats() function processes diagnostic data, it accesses the diag_dbgfs_dci_data_index variable which serves as a critical data structure pointer. The lack of proper locking mechanisms or atomic operations during this access creates opportunities for heap-based memory corruption. This condition can be triggered through malicious diagnostic commands or legitimate system operations that concurrently access the same memory regions, potentially leading to memory corruption that affects the stability and security of the entire system.
The operational impact of this vulnerability extends beyond simple system instability to potentially enable privilege escalation and arbitrary code execution within the kernel space. Attackers who can control the timing of concurrent access patterns or manipulate diagnostic interfaces may exploit this race condition to overwrite critical kernel memory structures, leading to system crashes, data corruption, or more severe consequences including complete system compromise. The vulnerability affects all Android releases from CAF (Code Aurora Forum) that utilize the Linux kernel, making it particularly widespread across mobile device implementations. This race condition specifically aligns with CWE-362, which identifies concurrent execution issues that can result in security vulnerabilities, and may map to ATT&CK technique T1068 related to exploiting vulnerabilities in the kernel or operating system.
Mitigation strategies for CVE-2017-15834 require immediate kernel-level patches that implement proper synchronization mechanisms around the diag_dbgfs_dci_data_index variable access. System administrators should prioritize applying security updates from device manufacturers and kernel maintainers that address the race condition through mutex locks, atomic operations, or other thread-safe programming constructs. Additionally, implementing monitoring solutions to detect abnormal diagnostic access patterns and restricting access to diagnostic interfaces can help reduce the attack surface. Organizations should also conduct thorough security assessments of their Android implementations to identify other potential race conditions in kernel modules and ensure proper thread synchronization mechanisms are in place throughout the system architecture. The fix typically involves adding appropriate locking mechanisms to ensure exclusive access to shared data structures during concurrent operations, thereby preventing the heap overflow conditions that could otherwise be exploited by malicious actors.