FreeBSD Ports Security Advisory FreeBSD-SA-01:46.w3m

FreeBSD Security Advisories security-advisories at
Tue Jul 10 07:37:49 PDT 2001


FreeBSD-SA-01:46                                           Security Advisory
                                                                FreeBSD, Inc.

Topic:          w3m contains remotely exploitable buffer overflow

Category:       ports
Module:         w3m
Announced:      2001-07-10
Credits:        OGASAWARA Satoshi   (LAC / s.ogaswr at
                KOBAYASHI Shigehiro (LAC / sigehiro at
Affects:        Ports collection prior to the correction date.
Corrected:      2001-06-19
Vendor status:  Updated version released
FreeBSD only:   NO

I.   Background

w3m is a console-based web browser.

II.  Problem Description

The w3m port, versions prior to w3m-0.2.1_1, contains a buffer
overflow in the parsing of MIME headers.  A malicious server which
is visited by a user with the w3m browser can exploit the browser
security holes in order to execute arbitrary code on the local
machine as the local user.

The w3m 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 5400 third-party applications in a ready-to-install
format. The ports collection shipped with FreeBSD 4.3 is vulnerable
to this problem since it was discovered after its release.

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

A malicious server which is visited by a user with the w3m browser
can exploit the browser security holes in order to execute arbitrary
code as the local user.

If you have not chosen to install the w3m port/package, then
your system is not vulnerable to this problem.

IV.  Workaround

Deinstall the w3m port/package if you have installed it.

V.   Solution

One of the following:

1) Upgrade your entire ports collection and rebuild the w3m port.

2) Deinstall the old package and install a new package dated after the
correction date, obtained from the following directories:


Packages are not automatically generated for the alpha architecture at
this time due to lack of build resources.

3) download a new port skeleton for the w3m port from:

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:

Version: GnuPG v1.0.6 (FreeBSD)
Comment: FreeBSD: The Power To Serve


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