SecurityTracker.com
Keep Track of the Latest Vulnerabilities
with SecurityTracker!
    Home    |    View Topics    |    Search    |    Contact Us    |   

SecurityTracker
Archives


 
Sign Up
Sign Up for Your FREE Weekly SecurityTracker E-mail Alert Summary
Instant Alerts
Buy our Premium Vulnerability Notification Service to receive customized, instant alerts
Affiliates
Put SecurityTracker Vulnerability Alerts on Your Web Site -- It's Free!
Partners
Become a Partner and License Our Database or Notification Service
Report a Bug
Report a vulnerability that you have found to SecurityTracker
bugs
@
securitytracker.com






Category:   OS (UNIX)  >   FreeBSD Kernel Vendors:   FreeBSD
FreeBSD smbfs '..\' Input Validation Hole Lets Users Traverse the Directory
SecurityTracker Alert ID:  1016194
SecurityTracker URL:  http://securitytracker.com/id/1016194
CVE Reference:   CVE-2006-2654   (Links to External Site)
Date:  Jun 1 2006
Impact:   Disclosure of system information, Disclosure of user information, Modification of system information, Modification of user information
Fix Available:  Yes  Vendor Confirmed:  Yes  
Version(s): 4.10, 4.11, 5.3, 5.4, 5.5, 6.0, and 6.1
Description:   A vulnerability was reported in FreeBSD in the smbfs filesystem. A user can escape a chroot'd directory.

smbfs does not properly validate path names that contain a backslash character. A remote authenticated user can use specially crafted characters ('..\') in a directory name to escape a chroot'd directory. Other directories on the smbfs mounted filesystem can be accessed.

Mark Moseley discovered this vulnerability.

Impact:   A remote authenticated user can bypass chroot restrictions and access other directories on the target smbfs mounted filesystem.
Solution:   FreeBSD has provided the following solution information [quoted]:

Perform one of the following:

1) Upgrade your vulnerable system to 4-STABLE, 5-STABLE, or 6-STABLE,
or to the RELENG_6_1, RELENG_6_0, RELENG_5_5, RELENG_5_4, RELENG_5_3,
RELENG_4_11, or RELENG_4_10 security branch dated after the correction
date.

2) To patch your present system:

The following patches have been verified to apply to FreeBSD 4.10,
4.11, 5.3, 5.4, 5.5, 6.0, and 6.1 systems.

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

# fetch http://security.FreeBSD.org/patches/SA-06:16/smbfs.patch
# fetch http://security.FreeBSD.org/patches/SA-06:16/smbfs.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.

The FreeBSD advisory is available at:

http://security.FreeBSD.org/advisories/FreeBSD-SA-06:16.smbfs.asc

Vendor URL:  security.FreeBSD.org/advisories/FreeBSD-SA-06:16.smbfs.asc (Links to External Site)
Cause:   Access control error, Input validation error
Underlying OS:  

Message History:   None.


 Source Message Contents

Date:  Wed, 31 May 2006 22:50:47 +0000 (GMT)
Subject:  FreeBSD Security Advisory FreeBSD-SA-06:16.smbfs

-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

=============================================================================
FreeBSD-SA-06:16.smbfs                                      Security Advisory
                                                          The FreeBSD Project

Topic:          smbfs chroot escape

Category:       core
Module:         smbfs
Announced:      2006-05-31
Credits:        Mark Moseley
Affects:        All FreeBSD releases.
Corrected:      2006-05-31 22:31:21 UTC (RELENG_6, 6.1-STABLE)
                2006-05-31 22:31:42 UTC (RELENG_6_1, 6.1-RELEASE-p1)
                2006-05-31 22:32:04 UTC (RELENG_6_0, 6.0-RELEASE-p8)
                2006-05-31 22:32:22 UTC (RELENG_5, 5.5-STABLE)
                2006-05-31 22:32:49 UTC (RELENG_5_5, 5.5-RELEASE-p1)
                2006-05-31 22:33:17 UTC (RELENG_5_4, 5.4-RELEASE-p15)
                2006-05-31 22:33:41 UTC (RELENG_5_3, 5.3-RELEASE-p30)
                2006-05-31 22:34:32 UTC (RELENG_4, 4.11-STABLE)
                2006-05-31 22:34:53 UTC (RELENG_4_11, 4.11-RELEASE-p18)
                2006-05-31 22:35:32 UTC (RELENG_4_10, 4.10-RELEASE-p24)
CVE Name:       CVE-2006-2654

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

I.   Background

smbfs is a network file-system used to access file servers using the
SMB/CIFS protocol.  chroot(2) is system call designed to limit a
process's access to a particular subset of a file-system.

II.  Problem Description

smbfs does not properly sanitize paths containing a backslash
character; in particular the directory name '..\' is interpreted as
the parent directory by the SMB/CIFS server, but smbfs handles it in
the same manner as any other directory.

III. Impact

When inside a chroot environment which resides on a smbfs mounted
file-system it is possible for an attacker to escape out of this
chroot to any other directory on the smbfs mounted file-system.

IV.  Workaround

Mount the smbfs file-systems which need to be used with chroot on top,
in a way so the chroot directory is exactly on the mount point and not
a sub directory.

V.   Solution

Perform one of the following:

1) Upgrade your vulnerable system to 4-STABLE, 5-STABLE, or 6-STABLE,
or to the RELENG_6_1, RELENG_6_0, RELENG_5_5, RELENG_5_4, RELENG_5_3,
RELENG_4_11, or RELENG_4_10 security branch dated after the correction
date.

2) To patch your present system:

The following patches have been verified to apply to FreeBSD 4.10,
4.11, 5.3, 5.4, 5.5, 6.0, and 6.1 systems.

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

# fetch http://security.FreeBSD.org/patches/SA-06:16/smbfs.patch
# fetch http://security.FreeBSD.org/patches/SA-06:16/smbfs.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.

VI.  Correction details

The following list contains the revision numbers of each file that was
corrected in FreeBSD.

Branch                                                           Revision
  Path
- -------------------------------------------------------------------------
RELENG_4
  src/sys/fs/smbfs/smbfs_vnops.c                                 1.2.2.11
RELENG_4_11
  src/UPDATING                                             1.73.2.91.2.19
  src/sys/conf/newvers.sh                                  1.44.2.39.2.22
  src/sys/fs/smbfs/smbfs_vnops.c                             1.2.2.10.4.1
RELENG_4_10
  src/UPDATING                                             1.73.2.90.2.25
  src/sys/conf/newvers.sh                                  1.44.2.34.2.26
  src/sys/fs/smbfs/smbfs_vnops.c                             1.2.2.10.2.1
RELENG_5
  src/sys/fs/smbfs/smbfs_vnops.c                                 1.46.2.2
RELENG_5_5
  src/UPDATING                                             1.342.2.35.2.1
  src/sys/conf/newvers.sh                                   1.62.2.21.2.3
  src/sys/fs/smbfs/smbfs_vnops.c                             1.46.2.1.4.1
RELENG_5_4
  src/UPDATING                                            1.342.2.24.2.24
  src/sys/conf/newvers.sh                                  1.62.2.18.2.20
  src/sys/fs/smbfs/smbfs_vnops.c                             1.46.2.1.2.1
RELENG_5_3
  src/UPDATING                                            1.342.2.13.2.33
  src/sys/conf/newvers.sh                                  1.62.2.15.2.35
  src/sys/fs/smbfs/smbfs_vnops.c                                 1.46.4.1
RELENG_6
  src/sys/fs/smbfs/smbfs_vnops.c                                 1.61.2.2
RELENG_6_1
  src/UPDATING                                             1.416.2.22.2.3
  src/sys/conf/newvers.sh                                   1.69.2.11.2.3
  src/sys/fs/smbfs/smbfs_vnops.c                             1.61.2.1.2.1
RELENG_6_0
  src/UPDATING                                             1.416.2.3.2.13
  src/sys/conf/newvers.sh                                    1.69.2.8.2.9
  src/sys/fs/smbfs/smbfs_vnops.c                                 1.61.4.1
- -------------------------------------------------------------------------

VII. References

http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2006-2654

The following three references correspond to independent bugs which
affect the Linux kernel but have the same impact:
http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2006-1863
http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2006-1864
https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=189434

The latest revision of this advisory is available at
http://security.FreeBSD.org/advisories/FreeBSD-SA-06:16.smbfs.asc
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.4.3 (FreeBSD)

iD8DBQFEfhueFdaIBMps37IRAquuAJ0eCPAahUu19kdTjKpVHrrtQ9q16gCfZ5sC
xknjanFlpMxJAZ7iYSxBvcI=
=PvoL
-----END PGP SIGNATURE-----
_______________________________________________
freebsd-security@freebsd.org mailing list
http://lists.freebsd.org/mailman/listinfo/freebsd-security
To unsubscribe, send any mail to "freebsd-security-unsubscribe@freebsd.org"

 
 


Go to the Top of This SecurityTracker Archive Page





Home   |    View Topics   |    Search   |    Contact Us

Copyright 2014, SecurityGlobal.net LLC