CVE-2007-1000 in Linux
Summary
by MITRE
The ipv6_getsockopt_sticky function in net/ipv6/ipv6_sockglue.c in the Linux kernel before 2.6.20.2 allows local users to read arbitrary kernel memory via certain getsockopt calls that trigger a NULL dereference.
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Analysis
by VulDB Data Team • 12/19/2024
The vulnerability identified as CVE-2007-1000 represents a critical information disclosure flaw within the Linux kernel's IPv6 implementation. This issue resides in the ipv6_getsockopt_sticky function located in the net/ipv6/ipv6_sockglue.c source file, affecting all Linux kernel versions prior to 2.6.20.2. The vulnerability stems from improper handling of socket options during IPv6 socket operations, creating a pathway for unauthorized memory access that could potentially expose sensitive kernel data to local attackers.
The technical exploitation of this vulnerability occurs through crafted getsockopt system calls that trigger a NULL pointer dereference within the ipv6_getsockopt_sticky function. When a local user executes specific socket option retrieval operations on IPv6 sockets, the kernel fails to properly validate pointer references, resulting in a NULL dereference condition. This flaw allows attackers to read arbitrary kernel memory locations through the socket option interface, potentially accessing confidential information such as kernel stack contents, memory management structures, or other sensitive data that should remain protected from user-space access. The vulnerability is classified under CWE-476 as a NULL Pointer Dereference, which represents a fundamental programming error that can lead to information disclosure and potentially further exploitation.
The operational impact of this vulnerability extends beyond simple information disclosure, as it provides attackers with access to kernel memory that could contain sensitive data structures, cryptographic keys, or other confidential information. Local users who can execute the specific getsockopt calls can potentially extract kernel memory contents that may include network protocol state information, memory management data, or other sensitive kernel structures. This information disclosure could facilitate more sophisticated attacks, including privilege escalation attempts or the discovery of additional vulnerabilities within the kernel. The vulnerability is particularly concerning in multi-user environments where local privilege escalation could lead to complete system compromise, as the attacker gains access to kernel memory that should remain protected from user-space processes.
Mitigation strategies for CVE-2007-1000 primarily focus on applying the official kernel patch released by the Linux kernel development team. System administrators should immediately upgrade to Linux kernel version 2.6.20.2 or later, which contains the necessary fixes to prevent the NULL pointer dereference in the ipv6_getsockopt_sticky function. Additionally, organizations should implement proper access controls and monitoring to detect unauthorized socket option manipulation attempts. The vulnerability aligns with ATT&CK technique T1059.007 for Command and Scripting Interpreter: Python, as attackers might use Python scripts to craft the specific getsockopt calls needed to exploit this vulnerability. Network administrators should also consider implementing kernel hardening measures such as disabling unnecessary IPv6 features when not required, and monitoring for unusual socket option usage patterns that could indicate exploitation attempts. The fix implemented in the patched kernel version addresses the root cause by ensuring proper pointer validation before memory access operations, thereby preventing the NULL dereference condition that enabled the information disclosure.