Samba up to 4.4.0rc3 SMB1 UNIX Extensions Symlink access control

CVSS Meta Temp Score
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CTI Interest Score
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6.8$0-$5k0.00

Summaryinfo

A vulnerability was found in Samba up to 4.4.0rc3. It has been rated as critical. The impacted element is an unknown function of the component SMB1 UNIX Extensions Symlink Handler. This manipulation causes access control. The identification of this vulnerability is CVE-2015-7560. It is possible to initiate the attack remotely. There is no exploit available. It is recommended to apply a patch to fix this issue.

Detailsinfo

A vulnerability has been found in Samba up to 4.4.0rc3 (File Transfer Software) and classified as critical. Affected by this vulnerability is an unknown function of the component SMB1 UNIX Extensions Symlink Handler. The manipulation with an unknown input leads to a access control vulnerability. The CWE definition for the vulnerability is CWE-284. The product does not restrict or incorrectly restricts access to a resource from an unauthorized actor. As an impact it is known to affect confidentiality, integrity, and availability.

The weakness was shared 03/09/2016 by Jeremy Allison as CVE-2015-7560.html as confirmed advisory (Website). It is possible to read the advisory at samba.org. This vulnerability is known as CVE-2015-7560. The attack can be launched remotely. The exploitation doesn't need any form of authentication. The technical details are unknown and an exploit is not publicly available. The attack technique deployed by this issue is T1068 according to MITRE ATT&CK. The advisory points out:

An authenticated malicious client can use SMB1 UNIX extensions to create a symlink to a file or directory, and then use non-UNIX SMB1 calls to overwrite the contents of the ACL on the file or directory linked to.

The vulnerability scanner Nessus provides a plugin with the ID 90267 (Amazon Linux AMI : samba (ALAS-2016-674)), which helps to determine the existence of the flaw in a target environment. It is assigned to the family Amazon Linux Local Security Checks. The commercial vulnerability scanner Qualys is able to test this issue with plugin 168811 (OpenSuSE Security Update for samba (openSUSE-SU-2016:1064-1)).

Upgrading to version 4.4.0rc4, 4.3.6, 4.2.9 or 4.1.23 eliminates this vulnerability. Applying a patch is able to eliminate this problem. It is possible to mitigate the problem by applying the configuration setting unix extensions = no; server min protocol = SMB2. The best possible mitigation is suggested to be patching the affected component.

The vulnerability is also documented in the databases at Tenable (90267), SecurityFocus (BID 84267†), SecurityTracker (ID 1035220†) and Vulnerability Center (SBV-57254†). Additional details are provided at seclists.org. The entries VDB-68821, VDB-69204, VDB-79858 and VDB-79859 are related to this item. Be aware that VulDB is the high quality source for vulnerability data.

Productinfo

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Website

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔍
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 6.9
VulDB Meta Temp Score: 6.8

VulDB Base Score: 7.3
VulDB Temp Score: 7.0
VulDB Vector: 🔍
VulDB Reliability: 🔍

NVD Base Score: 6.5
NVD Vector: 🔍

CVSSv2info

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VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔍
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Exploitinginfo

Class: Access control
CWE: CWE-284 / CWE-266
CAPEC: 🔍
ATT&CK: 🔍

Physical: No
Local: No
Remote: Yes

Availability: 🔍
Status: Not defined

EPSS Score: 🔍
EPSS Percentile: 🔍

Price Prediction: 🔍
Current Price Estimation: 🔍

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Nessus ID: 90267
Nessus Name: Amazon Linux AMI : samba (ALAS-2016-674)
Nessus File: 🔍
Nessus Risk: 🔍
Nessus Family: 🔍

OpenVAS ID: 703514
OpenVAS Name: Debian Security Advisory DSA 3514-1 (samba - security update)
OpenVAS File: 🔍
OpenVAS Family: 🔍

Qualys ID: 🔍
Qualys Name: 🔍

Threat Intelligenceinfo

Interest: 🔍
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Countermeasuresinfo

Recommended: Patch
Status: 🔍

0-Day Time: 🔍

Upgrade: Samba 4.4.0rc4/4.3.6/4.2.9/4.1.23
Config: unix extensions = no; server min protocol = SMB2

Timelineinfo

09/29/2015 🔍
03/09/2016 +162 days 🔍
03/09/2016 +0 days 🔍
03/10/2016 +1 days 🔍
03/13/2016 +3 days 🔍
03/13/2016 +0 days 🔍
03/14/2016 +1 days 🔍
07/10/2022 +2309 days 🔍

Sourcesinfo

Product: samba.org

Advisory: CVE-2015-7560.html
Researcher: Jeremy Allison
Status: Confirmed

CVE: CVE-2015-7560 (🔍)
GCVE (CVE): GCVE-0-2015-7560
GCVE (VulDB): GCVE-100-81319

OVAL: 🔍

SecurityFocus: 84267
SecurityTracker: 1035220 - Samba SMB1 UNIX Extensions Symlink Flaw Lets Remote Authenticated Users Overwrite Access Control Lists
Vulnerability Center: 57254 - Samba Remote File System Write via Arbitrary ACLs Modification, Medium

Misc.: 🔍
See also: 🔍

Entryinfo

Created: 03/10/2016 10:23
Updated: 07/10/2022 09:00
Changes: 03/10/2016 10:23 (46), 03/28/2017 17:52 (29), 07/10/2022 08:55 (3), 07/10/2022 08:56 (11), 07/10/2022 09:00 (1)
Complete: 🔍
Cache ID: 216::103

Be aware that VulDB is the high quality source for vulnerability data.

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