CVE-2016-2119

samba: Client side SMB2/3 required signing can be downgraded

Severity Score

7.5

*CVSS v3.1

Exploit Likelihood

*EPSS

Affected Versions

*CPE

Public Exploits

*Multiple Sources

Exploited in Wild

*KEV

Decision

*SSVC

Descriptions

libcli/smb/smbXcli_base.c in Samba 4.x before 4.2.14, 4.3.x before 4.3.11, and 4.4.x before 4.4.5 allows man-in-the-middle attackers to bypass a client-signing protection mechanism, and consequently spoof SMB2 and SMB3 servers, via the (1) SMB2_SESSION_FLAG_IS_GUEST or (2) SMB2_SESSION_FLAG_IS_NULL flag.

ibcli/smb/smbXcli_base.c en Samba 4.x en versiones anteriores a 4.2.14, 4.3.x en versiones anteriores a 4.3.11 y 4.4.x en versiones anteriores a 4.4.5 permite a atacantes man-in-the-middle eludir el mecanismo de protección de firmado de cliente y consecuentemente suplantar los servidores SMB2 y SMB3, a través de los indicadores (1) SMB2_SESSION_FLAG_IS_GUEST o (2) SMB2_SESSION_FLAG_IS_NULL.

A flaw was found in the way Samba initiated signed DCE/RPC connections. A man-in-the-middle attacker could use this flaw to downgrade the connection to not use signing and therefore impersonate the server.

*Credits: N/A

CVSS Scores

Attack Vector

Network

Attack Complexity

High

Privileges Required

None

User Interaction

Required

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

High

Attack Vector

Adjacent

Attack Complexity

High

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

High

Attack Vector

Network

Attack Complexity

Medium

Authentication

None

Confidentiality

Partial

Integrity

Partial

Availability

Partial

Attack Vector

Adjacent

Attack Complexity

Medium

Authentication

None

Confidentiality

Partial

Integrity

Partial

Availability

Partial

* Common Vulnerability Scoring System

SSVC

Decision:-

Exploitation

Automatable

Tech. Impact

* Organization's Worst-case Scenario

Timeline

2016-01-29 CVE Reserved
2016-07-07 CVE Published
2024-02-23 EPSS Updated
2024-08-05 CVE Updated
---------- Exploited in Wild
---------- KEV Due Date
---------- First Exploit

CWE

CWE-94: Improper Control of Generation of Code ('Code Injection')

CAPEC

References (11)

URL	Tag	Source
http://www.oracle.com/technetwork/topics/security/linuxbulletinjul2016-3090544.html	Third Party Advisory
http://www.securityfocus.com/bid/91700	Third Party Advisory
http://www.securitytracker.com/id/1036244	Third Party Advisory

URL	Date	SRC

URL	Date	SRC

URL	Date	SRC
http://lists.opensuse.org/opensuse-updates/2016-07/msg00060.html	2022-08-29
http://rhn.redhat.com/errata/RHSA-2016-1486.html	2022-08-29
http://rhn.redhat.com/errata/RHSA-2016-1487.html	2022-08-29
http://rhn.redhat.com/errata/RHSA-2016-1494.html	2022-08-29
https://security.gentoo.org/glsa/201805-07	2022-08-29
https://www.samba.org/samba/security/CVE-2016-2119.html	2022-08-29
https://access.redhat.com/security/cve/CVE-2016-2119	2016-07-26
https://bugzilla.redhat.com/show_bug.cgi?id=1351955	2016-07-26

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"				>= 4.0.0 < 4.2.14 Search vendor "Samba" for product "Samba" and version " >= 4.0.0 < 4.2.14"		-		Affected
Samba Search vendor "Samba"		Samba Search vendor "Samba" for product "Samba"				>= 4.3.0 < 4.3.11 Search vendor "Samba" for product "Samba" and version " >= 4.3.0 < 4.3.11"		-		Affected
Samba Search vendor "Samba"		Samba Search vendor "Samba" for product "Samba"				>= 4.4.0 < 4.4.5 Search vendor "Samba" for product "Samba" and version " >= 4.4.0 < 4.4.5"		-		Affected