exploit the possibilities

FreeBSD Security Advisory - sendfile(2) Kernel Memory Disclosure

FreeBSD Security Advisory - sendfile(2) Kernel Memory Disclosure
Posted Sep 10, 2013
Authored by Ed Maste | Site security.freebsd.org

FreeBSD Security Advisory - The sendfile(2) system call allows a server application (such as an HTTP or FTP server) to transmit the contents of a file over a network connection without first copying it to application memory. High performance servers such as Apache and ftpd use sendfile. On affected systems, if the length passed to sendfile(2) is non-zero and greater than the length of the file being transmitted, sendfile(2) will pad the transmission up to the requested length or the next pagesize boundary, whichever is smaller. The content of the additional bytes transmitted in this manner depends on the underlying filesystem, but may potentially include information useful to an attacker. An unprivileged user with the ability to run arbitrary code may be able to obtain arbitrary kernel memory contents.

tags | advisory, web, arbitrary, kernel
systems | freebsd
advisories | CVE-2013-5666
MD5 | 5b77f46ddda4cdbf66adc9fbaf7f4e9d

FreeBSD Security Advisory - sendfile(2) Kernel Memory Disclosure

Change Mirror Download
-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

=============================================================================
FreeBSD-SA-13:11.sendfile Security Advisory
The FreeBSD Project

Topic: Kernel memory disclosure in sendfile(2)

Category: core
Module: sendfile
Announced: 2013-09-10
Credits: Ed Maste
Affects: FreeBSD 9.2-RC1 and 9.2-RC2
Corrected: 2013-09-10 10:07:21 UTC (stable/9, 9.2-STABLE)
2013-09-10 10:08:20 UTC (releng/9.2, 9.2-RC1-p2)
2013-09-10 10:08:20 UTC (releng/9.2, 9.2-RC2-p2)
CVE Name: CVE-2013-5666

For general information regarding FreeBSD Security Advisories,
including descriptions of the fields above, security branches, and the
following sections, please visit <URL:http://security.FreeBSD.org/>.

I. Background

The sendfile(2) system call allows a server application (such as an
HTTP or FTP server) to transmit the contents of a file over a network
connection without first copying it to application memory. High
performance servers such as Apache and ftpd use sendfile.

II. Problem Description

On affected systems, if the length passed to sendfile(2) is non-zero
and greater than the length of the file being transmitted, sendfile(2)
will pad the transmission up to the requested length or the next
pagesize boundary, whichever is smaller.

The content of the additional bytes transmitted in this manner depends
on the underlying filesystem, but may potentially include information
useful to an attacker.

III. Impact

An unprivileged user with the ability to run arbitrary code may be
able to obtain arbitrary kernel memory contents.

IV. Workaround

No workaround is available.

V. Solution

Perform one of the following:

1) Upgrade your vulnerable system to a supported FreeBSD stable or
release / security branch (releng) dated after the correction date.

2) To update your vulnerable system via a source code patch:

The following patches have been verified to apply to the applicable
FreeBSD release branches.

a) Download the relevant patch from the location below, and verify the
detached PGP signature using your PGP utility.

[FreeBSD 9.2-STABLE]
# fetch http://security.FreeBSD.org/patches/SA-13:11/sendfile-9.2-stable.patch
# fetch http://security.FreeBSD.org/patches/SA-13:11/sendfile-9.2-stable.patch.asc
# gpg --verify sendfile-9.2-stable.patch.asc

[FreeBSD 9.2-RC1 and 9.2-RC2]
# fetch http://security.FreeBSD.org/patches/SA-13:11/sendfile-9.2-rc.patch
# fetch http://security.FreeBSD.org/patches/SA-13:11/sendfile-9.2-rc.patch.asc
# gpg --verify sendfile-9.2-rc.patch.asc

b) Apply the patch.

# cd /usr/src
# patch < /path/to/patch

c) Recompile your kernel as described in
<URL:http://www.FreeBSD.org/handbook/kernelconfig.html> and reboot the
system.

3) To update your vulnerable system via a binary patch:

Systems running a RELEASE version of FreeBSD on the i386 or amd64
platforms can be updated via the freebsd-update(8) utility:

# freebsd-update fetch
# freebsd-update install

VI. Correction details

The following list contains the correction revision numbers for each
affected branch.

Branch/path Revision
- -------------------------------------------------------------------------
stable/9/ r255443
releng/9.2/ r255444
- -------------------------------------------------------------------------

To see which files were modified by a particular revision, run the
following command, replacing NNNNNN with the revision number, on a
machine with Subversion installed:

# svn diff -cNNNNNN --summarize svn://svn.freebsd.org/base

Or visit the following URL, replacing NNNNNN with the revision number:

<URL:http://svnweb.freebsd.org/base?view=revision&revision=NNNNNN>

VII. References

<URL:http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2013-5666>

The latest revision of this advisory is available at
<URL:http://security.FreeBSD.org/advisories/FreeBSD-SA-13:11.sendfile.asc>
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.4.14 (FreeBSD)

iEYEARECAAYFAlIu8rIACgkQFdaIBMps37K01ACgmwaW3PZhjDqWSlTHusjIPNVy
A/YAn3DFUAvlX8sH89taM+sedjbD5In8
=gZwu
-----END PGP SIGNATURE-----
Login or Register to add favorites

File Archive:

October 2020

  • Su
  • Mo
  • Tu
  • We
  • Th
  • Fr
  • Sa
  • 1
    Oct 1st
    25 Files
  • 2
    Oct 2nd
    13 Files
  • 3
    Oct 3rd
    1 Files
  • 4
    Oct 4th
    1 Files
  • 5
    Oct 5th
    15 Files
  • 6
    Oct 6th
    15 Files
  • 7
    Oct 7th
    15 Files
  • 8
    Oct 8th
    11 Files
  • 9
    Oct 9th
    3 Files
  • 10
    Oct 10th
    1 Files
  • 11
    Oct 11th
    1 Files
  • 12
    Oct 12th
    8 Files
  • 13
    Oct 13th
    12 Files
  • 14
    Oct 14th
    23 Files
  • 15
    Oct 15th
    4 Files
  • 16
    Oct 16th
    13 Files
  • 17
    Oct 17th
    1 Files
  • 18
    Oct 18th
    1 Files
  • 19
    Oct 19th
    27 Files
  • 20
    Oct 20th
    41 Files
  • 21
    Oct 21st
    15 Files
  • 22
    Oct 22nd
    0 Files
  • 23
    Oct 23rd
    0 Files
  • 24
    Oct 24th
    0 Files
  • 25
    Oct 25th
    0 Files
  • 26
    Oct 26th
    0 Files
  • 27
    Oct 27th
    0 Files
  • 28
    Oct 28th
    0 Files
  • 29
    Oct 29th
    0 Files
  • 30
    Oct 30th
    0 Files
  • 31
    Oct 31st
    0 Files

Top Authors In Last 30 Days

File Tags

Systems

packet storm

© 2020 Packet Storm. All rights reserved.

Services
Security Services
Hosting By
Rokasec
close