CVE-2007-6151 in Linux
Summary
by MITRE
The isdn_ioctl function in isdn_common.c in Linux kernel 2.6.23 allows local users to cause a denial of service via a crafted ioctl struct in which iocts is not null terminated, which triggers a buffer overflow.
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Analysis
by VulDB Data Team • 08/04/2019
The vulnerability identified as CVE-2007-6151 represents a critical buffer overflow flaw within the Linux kernel's ISDN subsystem, specifically affecting versions up to and including 2.6.23. This issue resides in the isdn_ioctl function located in the isdn_common.c source file, which handles ioctl operations for ISDN (Integrated Services Digital Network) communication protocols. The flaw occurs when processing crafted ioctl structures that lack proper null termination, creating a condition where kernel memory can be overwritten beyond intended boundaries.
The technical implementation of this vulnerability stems from inadequate input validation within the kernel's ISDN driver interface. When a local user submits an ioctl command with a malformed structure where the iocts field is not null terminated, the kernel's processing routine fails to properly bounds-check the input data. This allows the buffer overflow to occur in kernel space, potentially overwriting adjacent memory locations including critical kernel data structures, function pointers, or stack variables. The vulnerability is classified as a buffer overflow under CWE-121, which specifically addresses stack-based buffer overflow conditions in programming environments.
The operational impact of CVE-2007-6151 extends beyond simple denial of service to potentially enable privilege escalation and system compromise. While the primary effect manifests as a denial of service through kernel crashes or system instability, the underlying buffer overflow condition creates opportunities for more sophisticated attacks. Attackers can leverage this vulnerability to corrupt kernel memory, potentially leading to arbitrary code execution in kernel space. This represents a significant concern from an attacker's perspective as it allows for elevation of privileges from local user to kernel level access, violating fundamental security principles of kernel isolation.
From a cybersecurity framework perspective, this vulnerability aligns with ATT&CK technique T1068, which covers 'Exploitation for Privilege Escalation', and T1499, covering 'Endpoint Denial of Service'. The vulnerability demonstrates the critical importance of input validation in kernel space operations, as outlined in the principle of least privilege and secure coding practices. Organizations should consider implementing kernel hardening measures including stack canaries, address space layout randomization, and kernel module signing to mitigate potential exploitation. The vulnerability also highlights the necessity of regular kernel updates and security patches, as this issue was resolved in subsequent kernel versions through proper bounds checking implementation and input validation mechanisms.
The remediation approach for CVE-2007-6151 requires immediate kernel version upgrades to patched releases, with administrators implementing comprehensive patch management processes to ensure all systems receive timely security updates. Additionally, system administrators should monitor for potential exploitation attempts through kernel log analysis and implement intrusion detection systems that can identify anomalous ioctl operations. The vulnerability serves as a reminder of the critical importance of maintaining current kernel versions and implementing robust security controls in kernel space operations to prevent similar issues from compromising system integrity and availability.