Amazon Linux AMI : kernel (ALAS-2020-1437)

high Nessus Plugin ID 141961
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Synopsis

The remote Amazon Linux AMI host is missing a security update.

Description

The version of tested product installed on the remote host is prior to tested version. It is, therefore, affected by multiple vulnerabilities as referenced in the ALAS-2020-1437 advisory.

- In the Linux kernel 5.0.21 and 5.3.11, mounting a crafted btrfs filesystem image, performing some operations, and then making a syncfs system call can lead to a use-after-free in try_merge_free_space in fs/btrfs/free-space-cache.c because the pointer to a left data structure can be the same as the pointer to a right data structure. (CVE-2019-19448)

- The VFIO PCI driver in the Linux kernel through 5.6.13 mishandles attempts to access disabled memory space. (CVE-2020-12888)

- A memory out-of-bounds read flaw was found in the Linux kernel before 5.9-rc2 with the ext3/ext4 file system, in the way it accesses a directory with broken indexing. This flaw allows a local user to crash the system if the directory exists. The highest threat from this vulnerability is to system availability.
(CVE-2020-14314)

- A flaw was found in the Linux kernels implementation of the invert video code on VGA consoles when a local attacker attempts to resize the console, calling an ioctl VT_RESIZE, which causes an out-of-bounds write to occur. This flaw allows a local user with access to the VGA console to crash the system, potentially escalating their privileges on the system. The highest threat from this vulnerability is to data confidentiality and integrity as well as system availability. (CVE-2020-14331)

- A flaw was found in the Linux kernel in versions before 5.9-rc6. When changing screen size, an out-of- bounds memory write can occur leading to memory corruption or a denial of service. Due to the nature of the flaw, privilege escalation cannot be fully ruled out. (CVE-2020-14390)

- A TOCTOU mismatch in the NFS client code in the Linux kernel before 5.8.3 could be used by local attackers to corrupt memory or possibly have unspecified other impact because a size check is in fs/nfs/nfs4proc.c instead of fs/nfs/nfs4xdr.c, aka CID-b4487b935452. (CVE-2020-25212)

- The rbd block device driver in drivers/block/rbd.c in the Linux kernel through 5.8.9 used incomplete permission checking for access to rbd devices, which could be leveraged by local attackers to map or unmap rbd block devices, aka CID-f44d04e696fe. (CVE-2020-25284)

- A race condition between hugetlb sysctl handlers in mm/hugetlb.c in the Linux kernel before 5.8.8 could be used by local attackers to corrupt memory, cause a NULL pointer dereference, or possibly have unspecified other impact, aka CID-17743798d812. (CVE-2020-25285)

- A flaw was found in the Linux kernel's implementation of biovecs in versions before 5.9-rc7. A zero-length biovec request issued by the block subsystem could cause the kernel to enter an infinite loop, causing a denial of service. This flaw allows a local attacker with basic privileges to issue requests to a block device, resulting in a denial of service. The highest threat from this vulnerability is to system availability. (CVE-2020-25641)

- A flaw was found in the HDLC_PPP module of the Linux kernel in versions before 5.9-rc7. Memory corruption and a read overflow is caused by improper input validation in the ppp_cp_parse_cr function which can cause the system to crash or cause a denial of service. The highest threat from this vulnerability is to data confidentiality and integrity as well as system availability. (CVE-2020-25643)

- A flaw was found in the Linux kernel in versions before 5.9-rc7. Traffic between two Geneve endpoints may be unencrypted when IPsec is configured to encrypt traffic for the specific UDP port used by the GENEVE tunnel allowing anyone between the two endpoints to read the traffic unencrypted. The main threat from this vulnerability is to data confidentiality. (CVE-2020-25645)

- A missing CAP_NET_RAW check in NFC socket creation in net/nfc/rawsock.c in the Linux kernel before 5.8.2 could be used by local attackers to create raw sockets, bypassing security mechanisms, aka CID-26896f01467a. (CVE-2020-26088)

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.

Solution

Run 'yum update kernel' to update your system.

See Also

https://alas.aws.amazon.com/ALAS-2020-1437.html

https://access.redhat.com/security/cve/CVE-2019-19448

https://access.redhat.com/security/cve/CVE-2020-12888

https://access.redhat.com/security/cve/CVE-2020-14314

https://access.redhat.com/security/cve/CVE-2020-14331

https://access.redhat.com/security/cve/CVE-2020-14390

https://access.redhat.com/security/cve/CVE-2020-25212

https://access.redhat.com/security/cve/CVE-2020-25284

https://access.redhat.com/security/cve/CVE-2020-25285

https://access.redhat.com/security/cve/CVE-2020-25641

https://access.redhat.com/security/cve/CVE-2020-25643

https://access.redhat.com/security/cve/CVE-2020-25645

https://access.redhat.com/security/cve/CVE-2020-26088

Plugin Details

Severity: High

ID: 141961

File Name: ala_ALAS-2020-1437.nasl

Version: 1.2

Type: local

Agent: unix

Published: 10/28/2020

Updated: 10/28/2020

Dependencies: ssh_get_info.nasl

Risk Information

CVSS Score Source: CVE-2020-25643

VPR

Risk Factor: Medium

Score: 6.7

CVSS v2

Risk Factor: High

Base Score: 7.5

Temporal Score: 5.5

Vector: AV:N/AC:M/Au:S/C:P/I:P/A:C

Temporal Vector: E:U/RL:OF/RC:C

CVSS v3

Risk Factor: High

Base Score: 7.2

Temporal Score: 6.3

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

Temporal Vector: E:U/RL:O/RC:C

Vulnerability Information

CPE: p-cpe:/a:amazon:linux:kernel, p-cpe:/a:amazon:linux:kernel-debuginfo, p-cpe:/a:amazon:linux:kernel-debuginfo-common-i686, p-cpe:/a:amazon:linux:kernel-debuginfo-common-x86_64, p-cpe:/a:amazon:linux:kernel-devel, p-cpe:/a:amazon:linux:kernel-headers, p-cpe:/a:amazon:linux:kernel-tools, p-cpe:/a:amazon:linux:kernel-tools-debuginfo, p-cpe:/a:amazon:linux:kernel-tools-devel, p-cpe:/a:amazon:linux:perf, p-cpe:/a:amazon:linux:perf-debuginfo, cpe:/o:amazon:linux

Required KB Items: Host/local_checks_enabled, Host/AmazonLinux/release, Host/AmazonLinux/rpm-list

Exploit Ease: No known exploits are available

Patch Publication Date: 10/26/2020

Vulnerability Publication Date: 12/8/2019

Reference Information

CVE: CVE-2019-19448, CVE-2020-12888, CVE-2020-14314, CVE-2020-14331, CVE-2020-14390, CVE-2020-25212, CVE-2020-25284, CVE-2020-25285, CVE-2020-25641, CVE-2020-25643, CVE-2020-25645, CVE-2020-26088

ALAS: 2020-1437