CVE-2017-7494

Description

A remote code execution flaw was found in Samba. A malicious authenticated samba client, having write access to the samba share, could use this flaw to execute arbitrary code as root.

Statement

This vulnerability exists in the samba server, client side packages are not affected.

Mitigation

Any of the following:

1. SELinux is enabled by default and our default policy prevents loading of modules from outside of samba's module directories and therefore blocks the exploit

2. Mount the filesystem which is used by samba for its writable share using "noexec" option.

3. Add the parameter:

    nt pipe support = no

    to the [global] section of your smb.conf and restart smbd. This prevents clients from accessing any named pipe endpoints. Note this can disable some expected functionality for Windows clients.

Common Vulnerability Scoring System (CVSS) Score Details

Info alert:Important note

CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).

CVSS v3 Score Breakdown

Red HatNVDcve.org
Base Score7.59.8N/A
Attack VectorNetworkNetworkN/A
Attack ComplexityHighLowN/A
Privileges RequiredLowNoneN/A
User InteractionNoneNoneN/A
ScopeUnchangedUnchangedN/A
ConfidentialityHighHighN/A
Integrity ImpactHighHighN/A
Availability ImpactHighHighN/A

Vector

Red Hat: CVSS:3.0/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H

NVD: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Acknowledgements

Red Hat would like to thank the Samba project for reporting this issue. Upstream acknowledges steelo as the original reporter.

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