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Gentoo Linux Security Advisory GLSA 200404-21 |
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http://security.gentoo.org/ |
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Severity: Normal |
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Title: Multiple Vulnerabilities in Samba |
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Date: April 29, 2004 |
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Bugs: #41800, #45965 |
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ID: 200404-21 |
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Synopsis |
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======== |
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|
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There is a bug in smbfs which may allow local users to gain root via a |
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setuid file on a mounted Samba share. Also, there is a tmpfile symlink |
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vulnerability in the smbprint script distributed with Samba. |
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|
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Background |
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========== |
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|
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Samba is a package which allows UNIX systems to act as file servers for |
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Windows computers. It also allows UNIX systems to mount shares exported |
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by a Samba/CIFS/Windows server. smbmount is a program in the Samba |
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package which allows normal users on a UNIX system to mount remote |
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shares. smbprint is an example script included in the Samba package |
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which can be used to facilitate network printing. |
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|
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Affected packages |
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================= |
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|
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------------------------------------------------------------------- |
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Package / Vulnerable / Unaffected |
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------------------------------------------------------------------- |
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1 net-fs/samba <= 3.0.2a >= 3.0.2a-r2 |
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|
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Description |
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=========== |
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|
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Two vulnerabilities have been discovered in Samba. The first |
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vulnerability allows a local user who has access to the smbmount |
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command to gain root. An attacker could place a setuid-root binary on a |
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Samba share/server he or she controls, and then use the smbmount |
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command to mount the share on the target UNIX box. The remote Samba |
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server must support UNIX extensions for this to work. This has been |
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fixed in version 3.0.2a. |
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|
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The second vulnerability is in the smbprint script. By creating a |
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symlink from /tmp/smbprint.log, an attacker could cause the smbprint |
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script to write to an arbitrary file on the system. This has been fixed |
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in version 3.0.2a-r2. |
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|
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Impact |
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====== |
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|
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Local users with access to the smbmount command may gain root access. |
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Also, arbitrary files may be overwritten using the smbprint script. |
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|
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Workaround |
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========== |
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|
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To workaround the setuid bug, remove the setuid bits from the |
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/usr/bin/smbmnt, /usr/bin/smbumount and /usr/bin/mount.cifs binaries. |
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However, please note that this workaround will prevent ordinary users |
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from mounting remote SMB and CIFS shares. |
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To work around the smbprint vulnerability, set "debug=no" in the |
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smbprint configuration. |
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Resolution |
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========== |
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All users should update to the latest version of the Samba package. |
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The following commands will perform the upgrade: |
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# emerge sync |
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# emerge -pv ">=net-fs/samba-3.0.2a-r2" |
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# emerge ">=net-fs/samba-3.0.2a-r2" |
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Those who are using Samba's password database also need to run the |
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following command: |
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# pdbedit --force-initialized-passwords |
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Those using LDAP for Samba passwords also need to check the |
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sambaPwdLastSet attribute on each account, and ensure it is not 0. |
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|
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References |
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========== |
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|
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[ 1 ] BugTraq Thread: Samba 3.x + kernel 2.6.x local root vulnerability |
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http://www.securityfocus.com/archive/1/353222/2004-04-09/2004-04-15/1 |
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[ 2 ] BugTraq: smbprint Vulnerability |
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http://seclists.org/lists/bugtraq/2004/Mar/0189.html |
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Availability |
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============ |
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This GLSA and any updates to it are available for viewing at |
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the Gentoo Security Website: |
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http://security.gentoo.org/glsa/glsa-200404-21.xml |
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Concerns? |
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========= |
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Security is a primary focus of Gentoo Linux and ensuring the |
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confidentiality and security of our users machines is of utmost |
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importance to us. Any security concerns should be addressed to |
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security@g.o or alternatively, you may file a bug at |
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http://bugs.gentoo.org. |
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License |
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======= |
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|
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Copyright 2004 Gentoo Technologies, Inc; referenced text |
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belongs to its owner(s). |
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|
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The contents of this document are licensed under the |
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Creative Commons - Attribution / Share Alike license. |
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|
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http://creativecommons.org/licenses/by-sa/1.0 |
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