FreeBSD Security Advisory FreeBSD-SA-01:37.slrn

FreeBSD Security Advisories security-advisories at
Mon Apr 23 20:25:22 PDT 2001


FreeBSD-SA-01:37                                           Security Advisory
                                                                FreeBSD, Inc.

Topic:          slrn contains remotely-exploitable buffer overflow

Category:       ports
Module:         slrn
Announced:      2001-04-23
Credits:        Bill Nottingham
Affects:        Ports collection prior to the correction date.
Corrected:      2001-04-04
Vendor status:  Updated version released
FreeBSD only:   NO

I.   Background

slrn is a slang-based NNTP news reader.

II.  Problem Description

The slrn port, versions prior to slrn-, contains a buffer
overflow in the wrapping/unwrapping functions of message header
parsing.  If a sufficiently long header is parsed, a buffer may
overflow allowing the execution of arbitrary code contained in a
message header as the user running the slrn program.

The slrn 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 5000 third-party applications in a ready-to-install format.  The
ports collections shipped with FreeBSD 3.5.1 and 4.2 contain this
problem since it was discovered after the releases.  The ports
collection that shipped with FreeBSD 4.3 is not vulnerable since this
problem was corrected prior to the 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

Arbitrary code may be executed on the local machine as the user
running the slrn program.

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

IV.  Workaround

Deinstall the slrn port/package, it you have installed it.

V.   Solution

One of the following:

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

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


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 slrn 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 v1.0.4 (FreeBSD)
Comment: FreeBSD: The Power To Serve


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