[ GLSA 200407-10 ] rsync: Directory traversal in rsync daemon

[GLSA]

Gentoo Linux Security Advisory

Title: rsync: Directory traversal in rsync daemon (GLSA 200407-10)
Severity: normal
Exploitable: remote
Date: July 12, 2004
Bug(s): #49534
ID: 200407-10

Synopsis

Under specific conditions, the rsync daemon is vulnerable to a directory traversal allowing to write files outside a sync module.

Background

rsync is a utility that provides fast incremental file transfers. It is used to efficiently synchronize files between hosts and is used by emerge to fetch Gentoo's Portage tree. rsyncd is the rsync daemon, which listens to connections from rsync clients.

Affected Packages

Package: net-misc/rsync
Vulnerable: <= 2.6.0-r1
Unaffected: >= 2.6.0-r2
Architectures: All supported architectures


Description

When rsyncd is used without chroot ("use chroot = false" in the rsyncd.conf file), the paths sent by the client are not checked thoroughly enough. If rsyncd is used with read-write permissions ("read only = false"), this vulnerability can be used to write files anywhere with the rights of the rsyncd daemon. With default Gentoo installations, rsyncd runs in a chroot, without write permissions and with the rights of the "nobody" user.

Impact

On affected configurations and if the rsync daemon runs under a privileged user, a remote client can exploit this vulnerability to completely compromise the host.

Workaround

You should never set the rsync daemon to run with "use chroot = false". If for some reason you have to run rsyncd without a chroot, then you should not set "read only = false".

Resolution

All users should update to the latest version of the rsync package.