Ubuntu 18.10 : linux-aws vulnerabilities (USN-3832-1)

High Nessus Plugin ID 119302

Synopsis

The remote Ubuntu host is missing one or more security-related patches.

Description

Jann Horn discovered that the procfs file system implementation in the Linux kernel did not properly restrict the ability to inspect the kernel stack of an arbitrary task. A local attacker could use this to expose sensitive information. (CVE-2018-17972)

Jann Horn discovered that the mremap() system call in the Linux kernel did not properly flush the TLB when completing, potentially leaving access to a physical page after it has been released to the page allocator. A local attacker could use this to cause a denial of service (system crash), expose sensitive information, or possibly execute arbitrary code. (CVE-2018-18281)

It was discovered that the BPF verifier in the Linux kernel did not correctly compute numeric bounds in some situations. A local attacker could use this to cause a denial of service (system crash) or possibly execute arbitrary code. (CVE-2018-18445)

Daniel Dadap discovered that the module loading implementation in the Linux kernel did not properly enforce signed module loading when booted with UEFI Secure Boot in some situations. A local privileged attacker could use this to execute untrusted code in the kernel.
(CVE-2018-18653)

Jann Horn discovered that the Linux kernel mishandles mapping UID or GID ranges inside nested user namespaces in some situations. A local attacker could use this to bypass access controls on resources outside the namespace. (CVE-2018-18955)

Philipp Wendler discovered that the overlayfs implementation in the Linux kernel did not properly verify the directory contents permissions from within a unprivileged user namespace. A local attacker could use this to expose sensitive information (protected file names). (CVE-2018-6559).

Note that Tenable Network Security has extracted the preceding description block directly from the Ubuntu security advisory. Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues.

Solution

Update the affected linux-image-4.18-aws and / or linux-image-aws packages.

See Also

https://usn.ubuntu.com/3832-1/

Plugin Details

Severity: High

ID: 119302

File Name: ubuntu_USN-3832-1.nasl

Version: 1.2

Type: local

Agent: unix

Published: 2018/11/30

Modified: 2018/12/07

Dependencies: 12634

Risk Information

Risk Factor: High

CVSS v2.0

Base Score: 7.2

Vector: CVSS2#AV:L/AC:L/Au:N/C:C/I:C/A:C

CVSS v3.0

Base Score: 7.8

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

Vulnerability Information

CPE: p-cpe:/a:canonical:ubuntu_linux:linux-image-4.18-aws, p-cpe:/a:canonical:ubuntu_linux:linux-image-aws, cpe:/o:canonical:ubuntu_linux:18.10

Required KB Items: Host/cpu, Host/Ubuntu, Host/Ubuntu/release, Host/Debian/dpkg-l

Exploit Available: true

Exploit Ease: Exploits are available

Patch Publication Date: 2018/11/30

Exploitable With

Metasploit (Linux Nested User Namespace idmap Limit Local Privilege Escalation)

Reference Information

CVE: CVE-2018-17972, CVE-2018-18281, CVE-2018-18445, CVE-2018-18653, CVE-2018-18955, CVE-2018-6559

USN: 3832-1