#VU32347 Permissions, Privileges, and Access Controls in Samba - CVE-2015-5252

Vulnerability identifier: #VU32347

Vulnerability risk: Medium

CVSSv4.0: 2.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N/E:U/U:Green]

CVE-ID: CVE-2015-5252

CWE-ID: CWE-264

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
Samba
Server applications / Directory software, identity management

Vendor: Samba

Description

The vulnerability allows a remote non-authenticated attacker to read and manipulate data.

vfs.c in smbd in Samba 3.x and 4.x before 4.1.22, 4.2.x before 4.2.7, and 4.3.x before 4.3.3, when share names with certain substring relationships exist, allows remote attackers to bypass intended file-access restrictions via a symlink that points outside of a share.

Mitigation
Install update from vendor's website.

Vulnerable software versions

Samba: 4.1.0 - 4.1.21, 4.2.0 - 4.2.6, 4.3.0 - 4.3.2

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External links
https://lists.fedoraproject.org/pipermail/package-announce/2015-December/174076.html
https://lists.fedoraproject.org/pipermail/package-announce/2015-December/174391.html
https://lists.opensuse.org/opensuse-security-announce/2015-12/msg00019.html
https://lists.opensuse.org/opensuse-security-announce/2015-12/msg00020.html
https://lists.opensuse.org/opensuse-security-announce/2015-12/msg00032.html
https://lists.opensuse.org/opensuse-security-announce/2015-12/msg00033.html
https://lists.opensuse.org/opensuse-security-announce/2016-01/msg00002.html
https://lists.opensuse.org/opensuse-security-announce/2016-01/msg00017.html
https://lists.opensuse.org/opensuse-security-announce/2016-04/msg00042.html
https://lists.opensuse.org/opensuse-security-announce/2016-04/msg00046.html
https://lists.opensuse.org/opensuse-security-announce/2016-04/msg00047.html
https://lists.opensuse.org/opensuse-security-announce/2016-04/msg00048.html
https://www.debian.org/security/2016/dsa-3433
https://www.oracle.com/technetwork/topics/security/bulletinjan2016-2867206.html
https://www.oracle.com/technetwork/topics/security/linuxbulletinjan2016-2867209.html
https://www.securityfocus.com/bid/79733
https://www.securitytracker.com/id/1034493
https://www.ubuntu.com/usn/USN-2855-1
https://www.ubuntu.com/usn/USN-2855-2
https://bugzilla.redhat.com/show_bug.cgi?id=1290288
https://git.samba.org/?p=samba.git;a=commit;h=4278ef25f64d5fdbf432ff1534e275416ec9561e
https://h20566.www2.hpe.com/portal/site/hpsc/public/kb/docDisplay?docId=emr_na-c05115993
https://security.gentoo.org/glsa/201612-47
https://www.samba.org/samba/security/CVE-2015-5252.html

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Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.