#VU41049 Permissions, Privileges, and Access Controls in Linux kernel - CVE-2014-8989

Vulnerability identifier: #VU41049

Vulnerability risk: Medium

CVSSv4.0: 1.2 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N/E:U/U:Green]

CVE-ID: CVE-2014-8989

CWE-ID: CWE-264

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
Linux kernel
Operating systems & Components / Operating system

Vendor: Linux Foundation

Description

The vulnerability allows a remote non-authenticated attacker to read and manipulate data.

The Linux kernel through 3.17.4 does not properly restrict dropping of supplemental group memberships in certain namespace scenarios, which allows local users to bypass intended file permissions by leveraging a POSIX ACL containing an entry for the group category that is more restrictive than the entry for the other category, aka a "negative groups" issue, related to kernel/groups.c, kernel/uid16.c, and kernel/user_namespace.c.

Mitigation
Install update from vendor's website.

Vulnerable software versions

Linux kernel: 3.0 - 3.0.68, 3.1 - 3.17.2, 3.2

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External links
https://lists.fedoraproject.org/pipermail/package-announce/2015-January/147864.html
https://lists.fedoraproject.org/pipermail/package-announce/2015-January/147973.html
https://thread.gmane.org/gmane.linux.man/7385/
https://www.mandriva.com/security/advisories?name=MDVSA-2015:058
https://www.openwall.com/lists/oss-security/2014/11/20/4
https://www.securityfocus.com/bid/71154
https://www.ubuntu.com/usn/USN-2515-1
https://www.ubuntu.com/usn/USN-2516-1
https://www.ubuntu.com/usn/USN-2517-1
https://www.ubuntu.com/usn/USN-2518-1

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Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.