local privilege escalation in rsync

The rsync suite provides client and server tools to easily support an administrator keeping the files of different machines in sync. In most private networks the rsync client tool is used via SSH to fulfill his tasks. In an open environment rsync is run in server mode accepting connections from many untrusted hosts with, but mostly without, authentication. The rsync server drops its root privileges soon after it was started and per default creates a chroot environment. Due to insufficient integer/bounds checking in the server code a heap overflow can be triggered remotely to execute arbitrary code. This code does not get executed as root and access is limited to the chroot environment. The chroot environment maybe broken afterwards by abusing further holes in system software or holes in the chroot setup.