CVE-2006-1528 in Linux
Summary
by MITRE
Linux kernel before 2.6.13 allows local users to cause a denial of service (crash) via a dio transfer from the sg driver to memory mapped (mmap) IO space.
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Analysis
by VulDB Data Team • 06/19/2019
The vulnerability described in CVE-2006-1528 represents a critical flaw in the Linux kernel's handling of direct I/O operations within the SCSI generic (sg) driver subsystem. This issue affects Linux kernel versions prior to 2.6.13 and demonstrates a fundamental problem in memory management and I/O handling that can be exploited by local attackers to trigger system crashes. The vulnerability specifically manifests when the sg driver attempts to transfer data directly to memory-mapped I/O space, creating a scenario where improper memory access can lead to system instability.
The technical root cause of this vulnerability lies in the kernel's failure to properly validate memory addresses when processing direct I/O transfers from the sg driver to memory-mapped regions. When a local user executes a crafted I/O operation, the kernel's memory management subsystem does not adequately check the validity of the target memory addresses within the mmap IO space. This lack of proper validation allows the system to attempt operations on invalid memory locations, resulting in kernel panics and system crashes. The flaw is categorized under CWE-125 as an out-of-bounds read condition that can lead to arbitrary code execution or system denial of service, though in this specific case the primary impact is the crash rather than code execution.
From an operational perspective, this vulnerability presents significant risks to Linux systems that rely on SCSI storage devices and direct I/O operations. Local users with minimal privileges can exploit this flaw to cause system-wide denial of service, effectively rendering the affected system unusable until manual reboot occurs. The impact extends beyond simple service disruption as system administrators must respond to these crashes, potentially leading to extended downtime and service interruptions in production environments. This vulnerability aligns with ATT&CK technique T1499.001 for network denial of service and represents a classic example of how kernel-level flaws can be leveraged to compromise system availability, particularly in server environments where continuous uptime is critical.
The recommended mitigation strategy involves immediate patching of the Linux kernel to version 2.6.13 or later, which includes the necessary fixes to properly validate memory addresses during direct I/O transfers. System administrators should also implement monitoring solutions to detect potential exploitation attempts and consider implementing additional security controls such as restricting access to the sg driver and limiting direct I/O operations where possible. Organizations should also review their system configurations to ensure that unnecessary SCSI device access is restricted, as this reduces the attack surface for potential exploitation of similar vulnerabilities. The fix implemented in kernel version 2.6.13 specifically addresses the memory validation issue in the sg driver's direct I/O handling code, preventing the kernel from attempting invalid memory operations that previously led to system crashes.