CVE-2015-7292 in Fire OS
Summary
by MITRE
Stack-based buffer overflow in the havok_write function in drivers/staging/havok/havok.c in Amazon Fire OS before 2016-01-15 allows attackers to cause a denial of service (panic) or possibly have unspecified other impact via a long string to /dev/hv.
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Analysis
by VulDB Data Team • 08/27/2020
The vulnerability identified as CVE-2015-7292 represents a critical stack-based buffer overflow flaw within the Amazon Fire OS kernel driver ecosystem. This issue resides in the havok_write function located in drivers/staging/havok/havok.c, specifically affecting Amazon Fire OS versions prior to the 2016-01-15 security update. The flaw manifests when the system processes data written to the /dev/hv device interface, creating a dangerous condition where attacker-controlled input can exceed the allocated stack buffer boundaries. The vulnerability operates at the kernel level, making it particularly dangerous as it can be exploited by malicious actors to compromise system stability and potentially execute arbitrary code within kernel space.
The technical implementation of this buffer overflow occurs through improper input validation within the havok_write function, which fails to adequately check the length of data being written to the device interface. When a malicious actor provides a long string input exceeding the predetermined stack buffer limits, the excess data overflows into adjacent memory locations, corrupting the stack frame and potentially overwriting critical function return addresses or local variables. This type of vulnerability falls under CWE-121 Stack-based Buffer Overflow, which is classified as a fundamental memory safety issue that has been consistently identified as a primary attack vector in kernel exploitation scenarios. The overflow condition directly maps to ATT&CK technique T1068, which describes the exploitation of vulnerabilities to execute code in kernel mode, and T1499, covering the use of kernel exploits for system disruption.
The operational impact of CVE-2015-7292 extends beyond simple denial of service conditions to encompass potential system instability and arbitrary code execution capabilities. The vulnerability can trigger kernel panics and system crashes, effectively causing denial of service attacks that render the affected Amazon Fire OS devices unusable. However, the potential for more severe consequences exists, as the buffer overflow could be leveraged to manipulate kernel memory structures, potentially allowing attackers to escalate privileges or execute malicious code with kernel-level permissions. The nature of the vulnerability makes it particularly attractive to threat actors seeking to compromise mobile devices running Amazon Fire OS, as it provides a direct path to kernel exploitation without requiring additional privilege escalation techniques.
Mitigation strategies for CVE-2015-7292 must focus on both immediate patching and defensive measures. The primary solution involves applying the security update released by Amazon on or before January 15, 2016, which addresses the buffer overflow by implementing proper input length validation and bounds checking within the havok_write function. Organizations and users should prioritize immediate deployment of this patch to prevent exploitation. Additional defensive measures include implementing proper input sanitization for device interfaces, monitoring for unusual patterns of data access to /dev/hv, and establishing robust kernel module access controls. The vulnerability serves as a reminder of the critical importance of kernel-level security in mobile operating systems and demonstrates how seemingly minor input validation flaws can result in significant system compromise. Network administrators should also consider implementing device access controls and monitoring mechanisms to detect potential exploitation attempts targeting this specific vulnerability.