DoS vulnerability in the Linux kernel
A vulnerability has been discovered in the Linux kernel, which enables an attacker to carry out a denial of service attack on server systems. This problem can occur if the affected Linux kernel versions use the EXT3 file system and share directories using the NFS protocol.
A manipulated UDP packet containing an NFS-v2 query with an invalid file handle can trigger a file system panic. This results in the exported directory being remounted as read-only. The error occurs as a result of the incorrect handling of invalid inode numbers in the EXT3 kernel code.
An error report on the Linux kernel mailing list includes a link to a proof of concept exploit. Administrators who work with EXT3 file systems and export directories using NFS should restrict access to exported directories to trusted computers or switch to a kernel version which is not affected by this vulnerability. According to security website SecurityFocus, the vulnerability affects all kernel versions from 2.6 to 188.8.131.52.
- Linux Kernel NFS and EXT3 Combination Remote Denial of Service Vulnerability, security bulletin from SecurityFocus
- Bad ext3/nfs DoS bug, bug report on the Linux kernel mailing list
- Entry on this vulnerability in the Common Vulnerabilities and Exposures database