[ SOURCE: http://www.secureroot.com/security/advisories/9678266177.html ]

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FreeBSD-SA-00:45                                           Security Advisory

                                                                FreeBSD, Inc.



Topic:          esound port allows file permissions to be modified



Category:       ports

Module:         esound

Announced:      2000-08-31

Credits:        Brian Feldman <green@FreeBSD.org> during internal auditing

Affects:        Ports collection prior to the correction date

Corrected:      2000-06-30

Vendor status:  Contacted

FreeBSD only:   NO



I.   Background



EsounD is a component of the GNOME desktop environment which is

responsible for multiplexing access to audio devices.



II.  Problem Description



The esound port, versions 0.2.19 and earlier, creates a world-writable

directory in /tmp owned by the user running the EsounD session, which

is used for the storage of a unix domain socket. A race condition

exists in the creation of this socket which allows a local attacker to

cause an arbitrary file or directory owned by the user running esound

to become world-writable. This can give the attacker access to the

victim's account, or lead to a system compromise if esound is run by

root.



The esound port is not installed by default, nor is it "part of

FreeBSD" as such: it is part of the FreeBSD ports collection, which

contains over 3700 third-party applications in a ready-to-install

format. The ports collections shipped with FreeBSD 4.0 and 3.5 contain

this problem, but it was corrected prior to the release of FreeBSD

4.1.



FreeBSD makes no claim about the security of these third-party

applications, although an effort is underway to provide a security

audit of the most security-critical ports.



III. Impact



Local users can cause files or directories owned by the target user to

become world-writable when that user runs the esd daemon (e.g. by

starting a GNOME session), allowing a security breach of that user

account (or the entire system if esd is run by root)



If you have not chosen to install the esound port/package, then your

system is not vulnerable to this problem.



IV.  Workaround



Deinstall the esound port/package, if you have installed it (see the

pkg_delete(1) manual page for more information).



V.   Solution



One of the following:



1) Upgrade your entire ports collection and rebuild the esound port.



2) Deinstall the old package and install a new package dated after the

correction date, obtained from:



ftp://ftp.FreeBSD.org/pub/FreeBSD/ports/i386/packages-3-stable/audio/esound-0.2.19.tgz

ftp://ftp.FreeBSD.org/pub/FreeBSD/ports/i386/packages-4-stable/audio/esound-0.2.19.tgz

ftp://ftp.FreeBSD.org/pub/FreeBSD/ports/alpha/packages-4-stable/audio/esound-0.2.19.tgz

ftp://ftp.FreeBSD.org/pub/FreeBSD/ports/i386/packages-5-current/audio/esound-0.2.19.tgz

ftp://ftp.FreeBSD.org/pub/FreeBSD/ports/alpha/packages-5-current/audio/esound-0.2.19.tgz



3) download a new port skeleton for the esound port from:



http://www.freebsd.org/ports/



and use it to rebuild the port.



4) Use the portcheckout utility to automate option (3) above. The

portcheckout port is available in /usr/ports/devel/portcheckout or the

package can be obtained from:



ftp://ftp.FreeBSD.org/pub/FreeBSD/ports/i386/packages-3-stable/devel/portcheckout-2.0.tgz

ftp://ftp.FreeBSD.org/pub/FreeBSD/ports/i386/packages-4-stable/devel/portcheckout-2.0.tgz

ftp://ftp.FreeBSD.org/pub/FreeBSD/ports/alpha/packages-4-stable/devel/portcheckout-2.0.tgz

ftp://ftp.FreeBSD.org/pub/FreeBSD/ports/i386/packages-5-current/devel/portcheckout-2.0.tgz

ftp://ftp.FreeBSD.org/pub/FreeBSD/ports/alpha/packages-5-current/devel/portcheckout-2.0.tgz



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