CVE-2011-2700 in Linux
Summary
by MITRE
Multiple buffer overflows in the si4713_write_econtrol_string function in drivers/media/radio/si4713-i2c.c in the Linux kernel before 2.6.39.4 on the N900 platform might allow local users to cause a denial of service or have unspecified other impact via a crafted s_ext_ctrls operation with a (1) V4L2_CID_RDS_TX_PS_NAME or (2) V4L2_CID_RDS_TX_RADIO_TEXT control ID.
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Analysis
by VulDB Data Team • 11/18/2021
The vulnerability described in CVE-2011-2700 represents a critical buffer overflow condition within the Linux kernel's radio driver implementation specifically affecting the si4713 chipset used in Nokia N900 devices. This flaw exists in the si4713_write_econtrol_string function located in the drivers/media/radio/si4713-i2c.c source file, where insufficient input validation and bounds checking allows maliciously crafted control operations to overwrite adjacent memory regions. The vulnerability affects kernel versions prior to 2.6.39.4 and specifically targets the V4L2 (Video4Linux2) control interface used for radio frequency operations.
The technical implementation of this vulnerability stems from improper handling of user-supplied data within the kernel space radio control subsystem. When a local user executes a crafted s_ext_ctrls system call with either V4L2_CID_RDS_TX_PS_NAME or V4L2_CID_RDS_TX_RADIO_TEXT control IDs, the si4713_write_econtrol_string function fails to properly validate the length of incoming data before copying it into fixed-size buffers. This classic buffer overflow condition occurs because the function does not enforce maximum length constraints on the data being written, allowing attackers to write beyond the allocated buffer boundaries. The vulnerability is classified under CWE-121 as a stack-based buffer overflow, where the function's stack allocated buffers are overwritten with malicious data.
The operational impact of this vulnerability extends beyond simple denial of service scenarios to potentially enable more severe security consequences. Local users can leverage this flaw to cause system crashes through kernel memory corruption, leading to complete system instability and denial of service conditions. Additionally, the unspecified other impacts mentioned in the CVE description suggest potential privilege escalation or information disclosure possibilities that could allow attackers to gain unauthorized access to kernel memory spaces. The attack vector requires local access to the system, making it a local privilege escalation risk that could be exploited by malicious users with basic system access, though the potential for remote exploitation cannot be entirely ruled out depending on system configurations. The vulnerability directly relates to the ATT&CK technique T1068 which involves exploiting local privilege escalation opportunities within operating system components.
Mitigation strategies for CVE-2011-2700 primarily focus on kernel version updates and input validation improvements. The most effective immediate solution involves upgrading the Linux kernel to version 2.6.39.4 or later, where the buffer overflow conditions have been addressed through proper bounds checking and input validation mechanisms. System administrators should also implement kernel hardening measures such as stack canaries, address space layout randomization, and kernel compile-time protections to reduce the exploitability of similar buffer overflow conditions. Additionally, monitoring for unauthorized s_ext_ctrls system calls and implementing access controls for radio device interfaces can help detect and prevent exploitation attempts. The vulnerability highlights the importance of thorough input validation in kernel space drivers and demonstrates how seemingly benign control operations can become attack vectors when proper bounds checking is absent. Organizations should also consider implementing security patches and updates through established vulnerability management processes to ensure all affected systems receive timely remediation.