CVE-2015-9289 in Linux
Summary
by MITRE
In the Linux kernel before 4.1.4, a buffer overflow occurs when checking userspace params in drivers/media/dvb-frontends/cx24116.c. The maximum size for a DiSEqC command is 6, according to the userspace API. However, the code allows larger values such as 23.
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Analysis
by VulDB Data Team • 11/13/2023
The vulnerability identified as CVE-2015-9289 represents a critical buffer overflow condition within the Linux kernel's digital video broadcasting subsystem, specifically affecting the cx24116 driver used for satellite communications. This flaw exists in kernel versions prior to 4.1.4 and stems from an improper validation of user-supplied parameters during the processing of DiSEqC (Digital Satellite Equipment Control) commands. The DiSEqC protocol is widely used in satellite receiver systems to communicate with external devices such as switches and tone burst generators, making this vulnerability particularly significant for systems relying on satellite-based media delivery.
The technical implementation of this vulnerability occurs within the drivers/media/dvb-frontends/cx24116.c file where the kernel fails to properly enforce the documented maximum size limit for DiSEqC commands. According to the userspace API specification, DiSEqC commands should be restricted to a maximum of six bytes, which aligns with standard satellite communication protocols and hardware limitations. However, the kernel code permits command sizes up to 23 bytes, creating a scenario where user-space applications can provide oversized data structures that exceed the allocated buffer boundaries. This discrepancy between the documented API limits and the actual kernel implementation creates a classic buffer overflow condition that can be exploited by malicious actors.
The operational impact of this vulnerability extends beyond simple memory corruption, as it provides potential attack vectors for privilege escalation and system compromise. An attacker capable of executing code in user-space can leverage this buffer overflow to overwrite adjacent memory locations, potentially leading to arbitrary code execution with kernel privileges. The vulnerability is particularly concerning because it affects the core kernel subsystem responsible for handling satellite communications, which means that exploitation could result in complete system compromise or denial of service conditions. The attack surface is further expanded by the widespread use of satellite-based media systems in consumer electronics, telecommunications infrastructure, and industrial applications where kernel-level vulnerabilities can have cascading effects across multiple systems.
From a cybersecurity perspective, this vulnerability aligns with CWE-121, which describes buffer overflow conditions in stack-based buffers, and represents a clear example of improper input validation in kernel space. The ATT&CK framework categorizes this type of vulnerability under privilege escalation techniques, specifically targeting the kernel execution environment through improper parameter handling. The vulnerability demonstrates how seemingly minor API specification discrepancies can lead to severe security implications, particularly when dealing with kernel-level drivers that handle hardware-specific protocols. Organizations using Linux-based systems for satellite communications, broadcast equipment, or any application relying on the cx24116 driver should immediately implement mitigation strategies including kernel updates, parameter validation enforcement, and monitoring for anomalous DiSEqC command patterns to prevent exploitation attempts that could compromise system integrity and data confidentiality.