Security restrictions bypass in Linux kernel - CVE-2018-18397

Vulnerability identifier: #VU16558

CSH Severity: Low

CVSS v4: 4.8 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N]

CVE-ID: CVE-2018-18397

CWE-ID: CWE-264

Exploitation vector: Local access

Exploit availability: Public exploit is available

The vulnerability allows a local attacker to bypass security restrictions on the target system.

The vulnerability exists due to improper access control in the userfaultfd implementation. A local attacker can access a system that is mounted with shmem or hugetlbs virtual memory areas, maliciously modify mapping to targeted files and write arbitrary memory on the system, which could be used to conduct additional attacks.

Linux kernel
Red Hat Enterprise Linux for ARM 64
Red Hat Enterprise Linux for Power 9
Red Hat Enterprise Linux for IBM System z (Structure A)
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 - AUS
Red Hat Enterprise Linux Server - TUS
Red Hat Enterprise Linux for Power, little endian - Extended Update Support
Red Hat Enterprise Linux for IBM z Systems - Extended Update Support
Red Hat Enterprise Linux EUS Compute Node
Red Hat Enterprise Linux for Power, big endian - Extended Update Support
Red Hat Enterprise Linux Server - Extended Update Support

kernel (Red Hat package)
kernel-alt (Red Hat package)
linux-azure (Ubuntu package)
linux-oracle (Ubuntu package)
linux-gcp (Ubuntu package)
linux-aws-hwe (Ubuntu 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
Red Hat Virtualization Host
BIG-IQ Centralized Management
BIG-IP AFM
BIG-IP Analytics
BIG-IP APM
BIG-IP ASM
BIG-IP LTM
BIG-IP FPS
BIG-IP GTM
BIG-IP PEM
BIG-IP Advanced WAF
BIG-IP AAM
BIG-IP DNS
BIG-IP Link Controller
BIG-IP DDHD
BIG-IP
BIG-IP SSLO

The vulnerability has been addressed in the versions 4.14.87, 4.19.8.

Linux kernel - addressed in versions 4.14.87, 4.19.8
kernel (Red Hat package) - addressed in versions 3.10.0-693.44.1.el7, 3.10.0-862.27.1.el7, 3.10.0-957.5.1.el7
kernel-alt (Red Hat package) - update to 4.14.0-115.7.1.el7a
linux-azure (Ubuntu package) - addressed in versions 4.15.0-1040.44, 4.15.0-1040.44~14.04.1
linux-oracle (Ubuntu package) - update to 4.15.0-1009.11~16.04.1
linux-gcp (Ubuntu package) - update to 4.15.0-1028.29~16.04.1
linux-aws-hwe (Ubuntu package) - update to 4.15.0-1033.35~16.04.1

• Exploit #6144 - Linux - 'userfaultfd' Bypasses tmpfs File Permissions (June 17, 2021)

• https://github.com/torvalds/linux/commit/29ec90660d68bbdd69507c1c8b4e33aa299278b1

• Multiple vulnerabilities in Linux Kernel
• Ubuntu update for Linux kernel (HWE)
• Red Hat update for kernel-alt
• Red Hat update for kernel
• Red Hat update for kernel
• Red Hat update for kernel
• Security restrictions bypass in Linux kernel in F5 Netwroks BIG-IP
• Security restrictions bypass in Linux kernel in F5 BIG-IQ Centralized Management