Incorrect permission assignment for critical resource in Linux kernel - CVE-2020-24394

Vulnerability identifier: #VU51240

CSH Severity: Low

CVSS v4: 8.4 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N]

CVE-ID: CVE-2020-24394

CWE-ID: CWE-732

Exploitation vector: Local access

Exploit availability: No public exploit available

The vulnerability allows a local user to bypass implemented security restrictions.

The vulnerability exists due to incorrect assignment of permissions on new filesystem objects when the filesystem lacks ACL support in fs/nfsd/vfs.c (in the NFS server). A local user can read and write arbitrary files on the system.

Linux kernel
Red Hat Enterprise Linux for Real Time for NFV
Red Hat Enterprise Linux for Real Time
Red Hat Enterprise Linux for Power, little endian
Red Hat Enterprise Linux for Scientific Computing
Red Hat Enterprise Linux for Power, big endian
Red Hat Enterprise Linux for IBM z Systems
Red Hat Enterprise Linux Desktop
Red Hat Enterprise Linux Workstation
Red Hat Enterprise Linux Server
Red Hat Enterprise Linux Server - TUS
Red Hat Enterprise Linux Server - AUS
Red Hat Enterprise Linux for IBM z Systems - Extended Update Support
Red Hat Enterprise Linux for Power, big endian - Extended Update Support
Red Hat Enterprise Linux EUS Compute Node
Red Hat Enterprise Linux for Power, little endian - Extended Update Support
Red Hat Virtualization Host - Extended Update Support 4.2 for RHEL
Red Hat Enterprise Linux for x86_64 - Extended Update Support
Ubuntu
kernel (Red Hat package)
Red Hat Enterprise Linux Server for x86_64 - Update Services for SAP Solutions
Red Hat Enterprise Linux Server for Power LE - Update Services for SAP Solutions
kernel-rt (Red Hat package)
linux-image-virtual (Ubuntu package)
linux-image-lowlatency (Ubuntu package)
linux-image-generic-lpae (Ubuntu package)
linux-image-generic (Ubuntu package)
linux-image-4.15.0-115-lowlatency (Ubuntu package)
linux-image-4.15.0-115-generic-lpae (Ubuntu package)
linux-image-4.15.0-115-generic (Ubuntu package)
linux-image-oracle (Ubuntu package)
linux-image-4.15.0-1051-oracle (Ubuntu package)
linux-image-oracle-lts-18.04 (Ubuntu package)
linux-image-4.15.0-1067-gke (Ubuntu package)
linux-image-gke (Ubuntu package)
linux-image-gke-4.15 (Ubuntu package)
linux-image-raspi2 (Ubuntu package)
linux-image-4.15.0-1068-raspi2 (Ubuntu package)
linux-image-kvm (Ubuntu package)
linux-image-4.15.0-1072-kvm (Ubuntu package)
linux-image-aws-hwe (Ubuntu package)
linux-image-aws-lts-18.04 (Ubuntu package)
linux-image-4.15.0-1080-aws (Ubuntu package)
linux-image-gcp (Ubuntu package)
linux-image-4.15.0-1081-gcp (Ubuntu package)
linux-image-gcp-lts-18.04 (Ubuntu package)
linux-image-snapdragon (Ubuntu package)
linux-image-4.15.0-1084-snapdragon (Ubuntu package)
linux-image-azure-lts-18.04 (Ubuntu package)
linux-image-azure (Ubuntu package)
linux-image-azure-edge (Ubuntu package)
linux-image-4.15.0-1093-azure (Ubuntu package)
linux-image-oem (Ubuntu package)
linux-image-4.15.0-1094-oem (Ubuntu package)
linux-image-5.3.0-65-lowlatency (Ubuntu package)
linux-image-5.3.0-65-generic (Ubuntu package)
linux-image-gkeop-5.3 (Ubuntu package)
linux-image-gke-5.3 (Ubuntu package)
linux-image-aws (Ubuntu package)
linux-image-5.3.0-1033-aws (Ubuntu package)
linux-image-5.3.0-1033-gke (Ubuntu package)
linux-image-5.3.0-1035-azure (Ubuntu package)
linux-image-oem-osp1 (Ubuntu package)
linux-image-5.4.0-45-lowlatency (Ubuntu package)
linux-image-5.4.0-45-generic-lpae (Ubuntu package)
linux-image-5.4.0-45-generic (Ubuntu package)
linux-image-virtual-hwe-18.04 (Ubuntu package)
linux-image-lowlatency-hwe-18.04 (Ubuntu package)
linux-image-gkeop-5.4 (Ubuntu package)
linux-image-generic-lpae-hwe-18.04 (Ubuntu package)
linux-image-generic-hwe-18.04 (Ubuntu package)
linux-image-snapdragon-hwe-18.04 (Ubuntu package)
linux-image-5.4.0-1016-raspi (Ubuntu package)
linux-image-raspi-hwe-18.04 (Ubuntu package)
linux-image-raspi (Ubuntu package)
linux-image-aws-edge (Ubuntu package)
linux-image-gke-5.4 (Ubuntu package)
linux-image-5.4.0-1022-aws (Ubuntu package)
linux-image-5.4.0-1022-gcp (Ubuntu package)
linux-image-5.4.0-1022-oracle (Ubuntu package)
linux-image-5.4.0-1023-azure (Ubuntu package)
Traffix SDC
Data Computing Appliance (DCA)
IBM QRadar Network Security
Session Smart Router

Install updates from vendor's website.

Linux kernel - update to 5.7.8
kernel (Red Hat package) - addressed in versions 3.10.0-693.82.1.el7, 3.10.0-957.70.1.el7, 3.10.0-1062.45.1.el7, 3.10.0-1160.11.1.el7
kernel-rt (Red Hat package) - update to 3.10.0-1160.11.1.rt56.1145.el7
Data Computing Appliance (DCA) - update to 4.3.0.0
linux-image-virtual (Ubuntu package) - addressed in versions 4.15.0.115.103, 5.4.0.45.49
linux-image-lowlatency (Ubuntu package) - addressed in versions 4.15.0.115.103, 5.4.0.45.49
linux-image-generic-lpae (Ubuntu package) - addressed in versions 4.15.0.115.103, 5.4.0.45.49
linux-image-generic (Ubuntu package) - addressed in versions 4.15.0.115.103, 5.4.0.45.49
linux-image-4.15.0-115-lowlatency (Ubuntu package) - update to 4.15.0-115.116~16.04.1
linux-image-4.15.0-115-generic-lpae (Ubuntu package) - update to 4.15.0-115.116~16.04.1
linux-image-4.15.0-115-generic (Ubuntu package) - update to 4.15.0-115.116~16.04.1
linux-image-oracle (Ubuntu package) - addressed in versions 4.15.0.1051.42, 5.4.0.1022.7, 5.4.0.1022.20
linux-image-4.15.0-1051-oracle (Ubuntu package) - addressed in versions 4.15.0-1051.55, 4.15.0-1051.55~16.04.1
linux-image-oracle-lts-18.04 (Ubuntu package) - update to 4.15.0.1051.62
linux-image-4.15.0-1067-gke (Ubuntu package) - update to 4.15.0-1067.70
linux-image-gke (Ubuntu package) - addressed in versions 4.15.0.1067.71, 4.15.0.1081.83, 5.4.0.1022.20
linux-image-gke-4.15 (Ubuntu package) - update to 4.15.0.1067.71
linux-image-raspi2 (Ubuntu package) - addressed in versions 4.15.0.1068.66, 5.4.0.1016.51
linux-image-4.15.0-1068-raspi2 (Ubuntu package) - update to 4.15.0-1068.72
linux-image-kvm (Ubuntu package) - addressed in versions 4.15.0.1072.68, 5.4.0.1021.20
linux-image-4.15.0-1072-kvm (Ubuntu package) - update to 4.15.0-1072.73
linux-image-aws-hwe (Ubuntu package) - update to 4.15.0.1080.77
linux-image-aws-lts-18.04 (Ubuntu package) - update to 4.15.0.1080.82
linux-image-4.15.0-1080-aws (Ubuntu package) - addressed in versions 4.15.0-1080.84, 4.15.0-1080.84~16.04.1
linux-image-gcp (Ubuntu package) - addressed in versions 4.15.0.1081.83, 5.4.0.1022.9, 5.4.0.1022.20
linux-image-4.15.0-1081-gcp (Ubuntu package) - addressed in versions 4.15.0-1081.92, 4.15.0-1081.92~16.04.1
linux-image-gcp-lts-18.04 (Ubuntu package) - update to 4.15.0.1081.99
linux-image-snapdragon (Ubuntu package) - update to 4.15.0.1084.87
linux-image-4.15.0-1084-snapdragon (Ubuntu package) - update to 4.15.0-1084.92
linux-image-azure-lts-18.04 (Ubuntu package) - update to 4.15.0.1093.67
linux-image-azure (Ubuntu package) - addressed in versions 4.15.0.1093.70, 4.15.0.1093.88, 5.3.0.1035.31, 5.4.0.1023.7, 5.4.0.1023.22
linux-image-azure-edge (Ubuntu package) - update to 4.15.0.1093.88
linux-image-4.15.0-1093-azure (Ubuntu package) - addressed in versions 4.15.0-1093.103, 4.15.0-1093.103~14.04.1, 4.15.0-1093.103~16.04.1
linux-image-oem (Ubuntu package) - addressed in versions 4.15.0.1094.98, 5.4.0.45.49
linux-image-4.15.0-1094-oem (Ubuntu package) - update to 4.15.0-1094.104
linux-image-5.3.0-65-lowlatency (Ubuntu package) - update to 5.3.0-65.59
linux-image-5.3.0-65-generic (Ubuntu package) - update to 5.3.0-65.59
linux-image-gkeop-5.3 (Ubuntu package) - update to 5.3.0.65.121
linux-image-gke-5.3 (Ubuntu package) - update to 5.3.0.1033.18
linux-image-aws (Ubuntu package) - addressed in versions 5.3.0.1033.32, 5.4.0.1022.23
linux-image-5.3.0-1033-aws (Ubuntu package) - update to 5.3.0-1033.35
linux-image-5.3.0-1033-gke (Ubuntu package) - update to 5.3.0-1033.35
linux-image-5.3.0-1035-azure (Ubuntu package) - update to 5.3.0-1035.36
IBM QRadar Network Security - addressed in versions 5.4.0.17, 5.5.0.12
linux-image-oem-osp1 (Ubuntu package) - update to 5.4.0.45.49
linux-image-5.4.0-45-lowlatency (Ubuntu package) - update to 5.4.0-45.49~18.04.2
linux-image-5.4.0-45-generic-lpae (Ubuntu package) - update to 5.4.0-45.49~18.04.2
linux-image-5.4.0-45-generic (Ubuntu package) - update to 5.4.0-45.49~18.04.2
linux-image-virtual-hwe-18.04 (Ubuntu package) - update to 5.4.0.45.49~18.04.38
linux-image-lowlatency-hwe-18.04 (Ubuntu package) - update to 5.4.0.45.49~18.04.38
linux-image-gkeop-5.4 (Ubuntu package) - update to 5.4.0.45.49~18.04.38
linux-image-generic-lpae-hwe-18.04 (Ubuntu package) - update to 5.4.0.45.49~18.04.38
linux-image-generic-hwe-18.04 (Ubuntu package) - update to 5.4.0.45.49~18.04.38
linux-image-snapdragon-hwe-18.04 (Ubuntu package) - update to 5.4.0.45.49~18.04.38
linux-image-5.4.0-1016-raspi (Ubuntu package) - update to 5.4.0-1016.17~18.04.1
linux-image-raspi-hwe-18.04 (Ubuntu package) - update to 5.4.0.1016.20
linux-image-raspi (Ubuntu package) - update to 5.4.0.1016.51
linux-image-aws-edge (Ubuntu package) - update to 5.4.0.1022.8
linux-image-gke-5.4 (Ubuntu package) - update to 5.4.0.1022.9
linux-image-5.4.0-1022-aws (Ubuntu package) - update to 5.4.0-1022.22~18.04.1
linux-image-5.4.0-1022-gcp (Ubuntu package) - update to 5.4.0-1022.22~18.04.1
linux-image-5.4.0-1022-oracle (Ubuntu package) - update to 5.4.0-1022.22~18.04.1
linux-image-5.4.0-1023-azure (Ubuntu package) - update to 5.4.0-1023.23~18.04.1
Session Smart Router - addressed in versions 5.4.7, 5.5.3

• http://lists.opensuse.org/opensuse-security-announce/2020-09/msg00007.html
• https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=962254
• https://cdn.kernel.org/pub/linux/kernel/v5.x/ChangeLog-5.7.8
• https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=22cf8419f1319ff87ec759d0ebdff4cbafaee832
• https://security.netapp.com/advisory/ntap-20200904-0003/
• https://usn.ubuntu.com/4465-1/
• https://usn.ubuntu.com/4483-1/
• https://usn.ubuntu.com/4485-1/

• Incorrect permission assignment in NFS server in Linux kernel
• Linux nfsd vulnerability in F5 Traffix SDC
• Red Hat Enterprise Linux 7.4 update for kernel
• Red Hat Enterprise Linux 7.6 update for kernel
• Multiple vulnerabilities in Juniper Networks Session Smart Router
• Multiple vulnerabilities in Dell EMC Data Computing Appliance (DCA)
• Multiple vulnerabilities in IBM QRadar Network Security
• Red Hat Enterprise Linux 7 update for kernel
• Red Hat Enterprise Linux 7 update for kernel-rt
• Red Hat Enterprise Linux 7.7 Extended Update Support update for kernel
• Ubuntu update for linux-aws-5.3
• Ubuntu update for linux
• Ubuntu update for linux