// For flags

CVE-2015-5296

samba: client requesting encryption vulnerable to downgrade attack

Severity Score

5.4
*CVSS v3.1

Exploit Likelihood

*EPSS

Affected Versions

*CPE

Public Exploits

0
*Multiple Sources

Exploited in Wild

-
*KEV

Decision

-
*SSVC
Descriptions

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 supports connections that are encrypted but unsigned, which allows man-in-the-middle attackers to conduct encrypted-to-unencrypted downgrade attacks by modifying the client-server data stream, related to clidfs.c, libsmb_server.c, and smbXcli_base.c.

Samba 3.x y 4.x en versiones anteriores a 4.1.22, 4.2.x en versiones anteriores a 4.2.7 y 4.3.x en versiones anteriores a 4.3.3 admite conexiones que están cifradas pero no firmadas, lo que permite a atacantes man-in-the-middle llevar a cabo un ataque de degradación de cifrado-a-descifrado modificando el flujo de datos cliente-servidor, relacionado con clidfs.c, libsmb_server.c y smbXcli_base.c.

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.

*Credits: N/A
CVSS Scores
Attack Vector
Network
Attack Complexity
High
Privileges Required
None
User Interaction
None
Scope
Changed
Confidentiality
Low
Integrity
Low
Availability
None
Attack Vector
Network
Attack Complexity
Medium
Authentication
None
Confidentiality
None
Integrity
Partial
Availability
None
Attack Vector
Network
Attack Complexity
Medium
Authentication
None
Confidentiality
Partial
Integrity
Partial
Availability
None
* Common Vulnerability Scoring System
SSVC
  • Decision:-
Exploitation
-
Automatable
-
Tech. Impact
-
* Organization's Worst-case Scenario
Timeline
  • 2015-07-01 CVE Reserved
  • 2015-12-29 CVE Published
  • 2023-11-08 EPSS Updated
  • 2024-08-06 CVE Updated
  • ---------- Exploited in Wild
  • ---------- KEV Due Date
  • ---------- First Exploit
CWE
  • CWE-20: Improper Input Validation
  • CWE-345: Insufficient Verification of Data Authenticity
CAPEC
References (26)
URL Tag Source
http://www.oracle.com/technetwork/topics/security/bulletinjan2016-2867206.html Third Party Advisory
http://www.oracle.com/technetwork/topics/security/linuxbulletinjan2016-2867209.html Third Party Advisory
http://www.securityfocus.com/bid/79732 Third Party Advisory
http://www.securitytracker.com/id/1034493 Third Party Advisory
https://git.samba.org/?p=samba.git%3Ba=commit%3Bh=1ba49b8f389eda3414b14410c7fbcb4041ca06b1 X_refsource_confirm
https://git.samba.org/?p=samba.git%3Ba=commit%3Bh=a819d2b440aafa3138d95ff6e8b824da885a70e9 X_refsource_confirm
https://git.samba.org/?p=samba.git%3Ba=commit%3Bh=d724f835acb9f4886c0001af32cd325dbbf1f895 X_refsource_confirm
https://h20566.www2.hpe.com/portal/site/hpsc/public/kb/docDisplay?docId=emr_na-c05115993 Third Party Advisory
URL Date SRC
URL Date SRC
URL Date SRC
http://lists.fedoraproject.org/pipermail/package-announce/2015-December/174076.html 2023-11-07
http://lists.fedoraproject.org/pipermail/package-announce/2015-December/174391.html 2023-11-07
http://lists.opensuse.org/opensuse-security-announce/2015-12/msg00019.html 2023-11-07
http://lists.opensuse.org/opensuse-security-announce/2015-12/msg00020.html 2023-11-07
http://lists.opensuse.org/opensuse-security-announce/2015-12/msg00032.html 2023-11-07
http://lists.opensuse.org/opensuse-security-announce/2015-12/msg00033.html 2023-11-07
http://lists.opensuse.org/opensuse-security-announce/2016-01/msg00002.html 2023-11-07
http://lists.opensuse.org/opensuse-security-announce/2016-01/msg00017.html 2023-11-07
http://lists.opensuse.org/opensuse-security-announce/2016-04/msg00042.html 2023-11-07
http://lists.opensuse.org/opensuse-security-announce/2016-04/msg00047.html 2023-11-07
http://lists.opensuse.org/opensuse-security-announce/2016-04/msg00048.html 2023-11-07
http://www.debian.org/security/2016/dsa-3433 2023-11-07
http://www.ubuntu.com/usn/USN-2855-1 2023-11-07
http://www.ubuntu.com/usn/USN-2855-2 2023-11-07
https://bugzilla.redhat.com/show_bug.cgi?id=1290292 2016-01-08
https://security.gentoo.org/glsa/201612-47 2023-11-07
https://www.samba.org/samba/security/CVE-2015-5296.html 2023-11-07
https://access.redhat.com/security/cve/CVE-2015-5296 2016-01-08
Affected Vendors, Products, and Versions
Vendor Product Version Other Status
Vendor Product Version Other Status <-- --> Vendor Product Version Other Status
Samba
Search vendor "Samba"
 Samba
Search vendor "Samba" for product "Samba"
 >= 3.2.0 < 4.1.22
Search vendor "Samba" for product "Samba" and version " >= 3.2.0 < 4.1.22"
-
Affected
Samba
Search vendor "Samba"
 Samba
Search vendor "Samba" for product "Samba"
 >= 4.2.0 < 4.2.7
Search vendor "Samba" for product "Samba" and version " >= 4.2.0 < 4.2.7"
-
Affected
Samba
Search vendor "Samba"
 Samba
Search vendor "Samba" for product "Samba"
 >= 4.3.0 < 4.3.3
Search vendor "Samba" for product "Samba" and version " >= 4.3.0 < 4.3.3"
-
Affected
Debian
Search vendor "Debian"
 Debian Linux
Search vendor "Debian" for product "Debian Linux"
 7.0
Search vendor "Debian" for product "Debian Linux" and version "7.0"
-
Affected
Debian
Search vendor "Debian"
 Debian Linux
Search vendor "Debian" for product "Debian Linux"
 8.0
Search vendor "Debian" for product "Debian Linux" and version "8.0"
-
Affected
Canonical
Search vendor "Canonical"
 Ubuntu Linux
Search vendor "Canonical" for product "Ubuntu Linux"
 12.04
Search vendor "Canonical" for product "Ubuntu Linux" and version "12.04"
-
Affected
Canonical
Search vendor "Canonical"
 Ubuntu Linux
Search vendor "Canonical" for product "Ubuntu Linux"
 14.04
Search vendor "Canonical" for product "Ubuntu Linux" and version "14.04"
esm
Affected
Canonical
Search vendor "Canonical"
 Ubuntu Linux
Search vendor "Canonical" for product "Ubuntu Linux"
 15.04
Search vendor "Canonical" for product "Ubuntu Linux" and version "15.04"
-
Affected
Canonical
Search vendor "Canonical"
 Ubuntu Linux
Search vendor "Canonical" for product "Ubuntu Linux"
 15.10
Search vendor "Canonical" for product "Ubuntu Linux" and version "15.10"
-
Affected