Linux NFS utils package contains remotely exploitable off-by-one bug. A local or remote attacker could exploit this vulnerability by sending a specially crafted request to rpc.mountd daemon.
Vulnerable systems:
* nfs-utils version 1.0.3 and prior
Immune systems:
* nfs-utils version 1.0.4 and above
An off-by-one bug exist in xlog() function which handles logging of requests. An overflow occurs when function is trying to add missing trailing new line character to logged string.
Due to miscalculation, if a string passed to the functions is equal or longer than 1023 bytes, the '\0' byte will be written beyond the buffer: - ------8<------cut-here------8<------
Impact:
Local or remote attacker that is capable of sending an RPC request to a vulnerable mount daemon could execute arbitrary code or cause denial of service.
Vendor status:
Vendor has been notified on June 10, 2003. The fix is incorporated in recent 1.0.4 release of nfs-utils.