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Moderate Samba4 Denial of Service Vulnerability in RHEL 6 RHSA-2016-0010-02

red hat
Calendar Grey January 8, 2016
Scroller Redhat
Updated samba4 packages have been released for Red Hat Enterprise Linux 6, addressing a range of moderate security vulnerabilities.
Updated samba4 packages that fix multiple security issues are now available for Red Hat Enterprise Linux 6

Solution

Before applying this update, make sure all previously released errata relevant to your system have been applied.

For details on how to apply this update, refer to:

https://access.redhat.com/articles/11258

Summary

Samba is an open-source implementation of the Server Message Block (SMB) or Common Internet File System (CIFS) protocol, which allows PC-compatible machines to share files, printers, and other information.
A denial of service flaw was found in the LDAP server provided by the AD DC in the Samba process daemon. A remote attacker could exploit this flaw by sending a specially crafted packet, which could cause the server to consume an excessive amount of memory and crash. (CVE-2015-7540)
Multiple buffer over-read flaws were found in the way Samba handled malformed inputs in certain encodings. An authenticated, remote attacker could possibly use these flaws to disclose portions of the server memory. (CVE-2015-5330)
A man-in-the-middle vulnerability was found in the way "connection signing" was implemented by Samba. A remote attacker could use this flaw to downgrade an existing Samba client connection and force the use of plain text. (CVE-2015-5296)
A missing access control flaw was found in Samba. A remote, authenticated attacker could use this flaw to view the current snapshot on a Samba share, despite not having DIRECTORY_LIST access rights. (CVE-2015-5299)
An access flaw was found in the way Samba verified symbolic links when creating new files on a Samba share. A remote attacker could exploit this flaw to gain access to files outside of Samba's share path. (CVE-2015-5252)
Red Hat would like to thank the Samba project for reporting these issues. Upstream acknowledges Stefan Metzmacher of the Samba Team and Sernet.de as the original reporters of CVE-2015-5296, partha@exablox.com as the original reporter of CVE-2015-5299, Jan "Yenya" Kasprzak and the Computer Systems Unit team at Faculty of Informatics, Masaryk University as the original reporters of CVE-2015-5252 flaws, and Douglas Bagnall as the original reporter of CVE-2015-5330.
All samba4 users are advised to upgrade to these updated packages, which contain backported patches to correct these issues. After installing this update, the smb service will be restarted automatically.

Topics%20covered

Topics Covered

security advisory moderate samba Red Hat Enterprise Linux DoS flaw access control issue LDAP attack

References

https://access.redhat.com/security/cve/CVE-2015-5252 https://access.redhat.com/security/cve/CVE-2015-5296 https://access.redhat.com/security/cve/CVE-2015-5299 https://access.redhat.com/security/cve/CVE-2015-5330 https://access.redhat.com/security/cve/CVE-2015-7540 https://access.redhat.com/security/updates/classification#moderate

Package List

Red Hat Enterprise Linux Desktop (v. 6):
Source: samba4-4.0.0-67.el6_7.rc4.src.rpm
i386: samba4-4.0.0-67.el6_7.rc4.i686.rpm samba4-client-4.0.0-67.el6_7.rc4.i686.rpm samba4-common-4.0.0-67.el6_7.rc4.i686.rpm samba4-dc-4.0.0-67.el6_7.rc4.i686.rpm samba4-dc-libs-4.0.0-67.el6_7.rc4.i686.rpm samba4-debuginfo-4.0.0-67.el6_7.rc4.i686.rpm samba4-devel-4.0.0-67.el6_7.rc4.i686.rpm samba4-libs-4.0.0-67.el6_7.rc4.i686.rpm samba4-pidl-4.0.0-67.el6_7.rc4.i686.rpm samba4-python-4.0.0-67.el6_7.rc4.i686.rpm samba4-swat-4.0.0-67.el6_7.rc4.i686.rpm samba4-test-4.0.0-67.el6_7.rc4.i686.rpm samba4-winbind-4.0.0-67.el6_7.rc4.i686.rpm samba4-winbind-clients-4.0.0-67.el6_7.rc4.i686.rpm samba4-winbind-krb5-locator-4.0.0-67.el6_7.rc4.i686.rpm
x86_64: samba4-4.0.0-67.el6_7.rc4.x86_64.rpm samba4-client-4.0.0-67.el6_7.rc4.x86_64.rpm samba4-common-4.0.0-67.el6_7.rc4.x86_64.rpm samba4-dc-4.0.0-67.el6_7.rc4.x86_64.rpm samba4-dc-libs-4.0.0-67.el6_7.rc4.x86_64.rpm samba4-debuginfo-4.0.0-67.el6_7.rc4.x86_64.rpm samba4-devel-4.0.0-67.el6_7.rc4.x86_64.rpm samba4-libs-4.0.0-67.el6_7.rc4.x86_64.rpm samba4-pidl-4.0.0-67.el6_7.rc4.x86_64.rpm samba4-python-4.0.0-67.el6_7.rc4.x86_64.rpm samba4-swat-4.0.0-67.el6_7.rc4.x86_64.rpm samba4-test-4.0.0-67.el6_7.rc4.x86_64.rpm

Read the Full Advisory


Advisory ID: RHSA-2016:0010-02
Product: Red Hat Enterprise Linux
Advisory URL: https://access.redhat.com/errata/RHSA-2016:0010.html
Issue date: 2016-01-07

Topic

Updated samba4 packages that fix multiple security issues are now availablefor Red Hat Enterprise Linux 6.Red Hat Product Security has rated this update as having Moderate securityimpact. Common Vulnerability Scoring System (CVSS) base scores, which givedetailed severity ratings, are available for each vulnerability from theCVE links in the References section.

Topics%20covered

Topics Covered

security advisory moderate samba Red Hat Enterprise Linux DoS flaw access control issue LDAP attack

Relevant Releases Architectures

Red Hat Enterprise Linux Desktop (v. 6) - i386, x86_64

Red Hat Enterprise Linux HPC Node (v. 6) - x86_64

Red Hat Enterprise Linux Server (v. 6) - i386, ppc64, s390x, x86_64

Red Hat Enterprise Linux Workstation (v. 6) - i386, x86_64

Bugs Fixed

1276126 - CVE-2015-5299 Samba: Missing access control check in shadow copy code

1281326 - CVE-2015-5330 samba, libldb: remote memory read in the Samba LDAP server

1288451 - CVE-2015-7540 samba: DoS to AD-DC due to insufficient checking of asn1 memory allocation

1290288 - CVE-2015-5252 samba: Insufficient symlink verification in smbd

1290292 - CVE-2015-5296 samba: client requesting encryption vulnerable to downgrade attack

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