CVE-2007-6206 in Linux
Summary
by MITRE
The do_coredump function in fs/exec.c in Linux kernel 2.4.x and 2.6.x up to 2.6.24-rc3, and possibly other versions, does not change the UID of a core dump file if it exists before a root process creates a core dump in the same location, which might allow local users to obtain sensitive information.
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Analysis
by VulDB Data Team • 08/02/2019
The vulnerability described in CVE-2007-6206 resides within the Linux kernel's core dump handling mechanism, specifically in the do_coredump function located in fs/exec.c. This flaw affects kernel versions 2.4.x through 2.6.24-rc3 and potentially other variants, creating a privilege escalation vector through improper file ownership handling during core dump creation. The issue manifests when a root process attempts to generate a core dump file in a location where one already exists, failing to properly update the file's user identifier even when the process has elevated privileges.
The technical implementation of this vulnerability stems from the kernel's failure to validate and enforce proper ownership changes when overwriting existing core dump files. When a root process creates a core dump, the system should ensure that the resulting file reflects the correct ownership, typically the user who initiated the process. However, the flawed implementation allows the core dump file to retain its original ownership, which can be exploited by local users to gain unauthorized access to sensitive information contained within the core dump. This behavior violates fundamental security principles of file system integrity and privilege separation.
The operational impact of this vulnerability extends beyond simple information disclosure, as it enables local users to potentially access sensitive data that should only be available to the process owner or system administrators. Core dump files often contain memory contents, stack traces, and potentially confidential information from the crashing process, making them valuable targets for attackers seeking to extract system secrets. The vulnerability particularly affects systems where multiple users share the same directory space, as the existing file ownership can inadvertently reveal information about other users' processes or data. This issue is classified under CWE-276, which addresses improper file permissions, and aligns with ATT&CK technique T1005 for data from local system.
Mitigation strategies for CVE-2007-6206 involve both immediate patching and operational security enhancements. System administrators should immediately upgrade to kernel versions 2.6.24 or later where this vulnerability has been resolved through proper implementation of file ownership handling during core dump creation. Additionally, organizations should implement restrictive file system permissions on directories where core dumps are stored, ensuring that only authorized users can create or modify core dump files. The implementation of mandatory access controls such as SELinux or AppArmor can provide additional layers of protection by enforcing strict policies around core dump file creation and access. Security monitoring should also be enhanced to detect unusual core dump creation patterns that might indicate exploitation attempts. The vulnerability demonstrates the critical importance of proper privilege handling in kernel space operations and highlights the need for rigorous security testing of core system functions that handle sensitive data processing and file system operations.