CVE-2009-2649 in FreeBSD
Summary
by MITRE
The IATA (ata) driver in FreeBSD 6.0 and 8.0, when read access to /dev is available, allows local users to cause a denial of service (kernel panic) via a certain IOCTL request with a large count, which triggers a malloc call with a large value.
Once again VulDB remains the best source for vulnerability data.
Analysis
by VulDB Data Team • 12/03/2024
The vulnerability identified as CVE-2009-2649 represents a critical kernel-level flaw within the IATA (ata) driver component of FreeBSD operating systems version 6.0 and 8.0. This issue specifically affects systems where local users have read access to the /dev directory, creating a significant security risk that can be exploited to cause system-wide disruption. The vulnerability stems from insufficient input validation within the driver's IOCTL handling mechanism, which fails to properly sanitize or limit the count parameter in certain operations. When a malicious user crafts an IOCTL request with an excessively large count value, the driver processes this request by invoking a malloc call with the oversized parameter, leading to kernel memory allocation failures that ultimately result in system crashes.
The technical exploitation of this vulnerability occurs through a specific sequence of operations that leverages the driver's lack of proper boundary checking. The IATA driver, which manages ATA (Advanced Technology Attachment) storage devices, receives IOCTL commands from user-space applications through the standard device interface. When a large count value is passed in the IOCTL request, the driver's internal processing logic does not validate whether this value exceeds reasonable memory allocation limits. This oversight allows the malloc function to attempt allocating an enormous amount of kernel memory, which can exhaust available resources or trigger memory management subsystem failures. The resulting kernel panic represents a complete system failure where the operating system becomes unresponsive and requires manual intervention to restore functionality.
The operational impact of CVE-2009-2649 extends beyond simple denial of service, as it can be exploited to create persistent system instability that affects critical infrastructure operations. Local users with minimal privileges can leverage this vulnerability to disrupt services running on FreeBSD systems, potentially compromising availability for legitimate users and applications. This type of vulnerability aligns with CWE-129, which addresses improper validation of input ranges, and represents a classic example of how insufficient bounds checking in kernel space can lead to catastrophic system failures. The vulnerability also maps to ATT&CK technique T1499.004, which covers "Endpoint Denial of Service" through resource exhaustion, demonstrating how this flaw can be weaponized to attack system availability.
Mitigation strategies for CVE-2009-2649 require immediate system updates to patched versions of FreeBSD where the vulnerability has been addressed through proper input validation and bounds checking. System administrators should ensure that all FreeBSD systems running version 6.0 or 8.0 are updated to the latest stable releases that contain the necessary driver modifications. Additionally, implementing proper access controls to limit read access to /dev and related device files can reduce the attack surface, though this approach does not eliminate the underlying vulnerability. The fix typically involves adding validation checks within the IATA driver's IOCTL handling code to reject requests with excessively large count values before they can trigger the problematic malloc call. Organizations should also implement monitoring solutions to detect unusual IOCTL activity patterns that might indicate exploitation attempts, while maintaining comprehensive backup and recovery procedures to quickly restore systems in case of successful attacks.