Improper access control in Linux kernel - CVE-2018-18281

Vulnerability identifier: #VU15643

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:N/SC:N/SI:N/SA:N]

CVE-ID: CVE-2018-18281

CWE-ID: CWE-284

Exploitation vector: Local access

Exploit availability: No public exploit available

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

The vulnerability exists due to improper access restrictions to memory when performing TLB flushes after dropping pagetable locks with mremap() syscall, A local user can access a physical page of a stale TLB entry after ftruncate() syscall is called to remove entries from the pagetables of a task that is in the middle of mremap() syscall.

Successful exploitation of the vulnerability may allow an attacker to gain access to sensitive information, stored in process memory.

Linux kernel
F5OS
Red Hat Enterprise Linux for Real Time for NFV
Red Hat Enterprise Linux for Real Time
Red Hat Enterprise Linux for Power 9
Red Hat Enterprise Linux for IBM System z (Structure A)
Red Hat Enterprise Linux Server
Red Hat Enterprise Linux Workstation
Red Hat Enterprise Linux Desktop
Red Hat Enterprise Linux for IBM z Systems
Red Hat Enterprise Linux for Power, big endian
Red Hat Enterprise Linux for Scientific Computing
Red Hat Enterprise Linux for Power, little endian
Red Hat Enterprise Linux for ARM 64
Red Hat Enterprise Linux Server - AUS
Red Hat Enterprise Linux Server - TUS
Red Hat Enterprise Linux EUS Compute Node
Red Hat Enterprise Linux for Power, big endian - Extended Update Support
Red Hat Enterprise Linux for IBM z Systems - Extended Update Support
Red Hat Enterprise Linux for x86_64 - Extended Update Support
Red Hat Enterprise Linux for Power, little endian - Extended Update Support
Red Hat Virtualization Host - Extended Update Support 4.2 for RHEL
Opensuse

BIG-IP
BIG-IP Service Proxy for Kubernetes (BIG-IP SPK)
MRG Realtime
kernel (Red Hat package)
kernel-rt (Red Hat package)
kernel-alt (Red Hat package)
Red Hat Enterprise Linux Server for Power LE - Update Services for SAP Solutions
Red Hat Enterprise Linux Server for x86_64 - Update Services for SAP Solutions
Red Hat Virtualization Host
BIG-IQ Centralized Management

Install updates from vendor's website.

Linux kernel - addressed in versions 4.9.135, 4.14.78, 4.18.16, 4.19
BIG-IP - addressed in versions 13.1.5, 14.1.4.6, 14.1.5, 15.1.5.1, 15.1.6, 16.1.2.2, 16.1.3
F5OS - update to 1.3.1
kernel (Red Hat package) - addressed in versions 3.10.0-693.62.1.el7, 3.10.0-862.46.1.el7, 3.10.0-957.43.1.el7, 3.10.0-1062.el7
kernel-rt (Red Hat package) - addressed in versions 3.10.0-693.62.1.rt56.659.el6rt, 3.10.0-1062.rt56.1022.el7
kernel-alt (Red Hat package) - update to 4.14.0-115.7.1.el7a

• http://packetstormsecurity.com/files/150001/Linux-mremap-TLB-Flush-Too-Late.html
• http://www.openwall.com/lists/oss-security/2018/10/29/5
• https://bugs.chromium.org/p/project-zero/issues/detail?id=1695
• https://cdn.kernel.org/pub/linux/kernel/v4.x/ChangeLog-4.14.78
• https://cdn.kernel.org/pub/linux/kernel/v4.x/ChangeLog-4.18.16
• https://cdn.kernel.org/pub/linux/kernel/v4.x/ChangeLog-4.9.135
• https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=eb66ae030829605d61fbef1909ce310e29f78821

• Security restrictions bypass in Linux Kernel
• OpenSUSE Linux update for the Linux Kernel
• Red Hat update for kernel-rt
• Red Hat update for kernel-alt
• Red Hat update for kernel
• Red Hat update for kernel
• Red Hat update for kernel-rt
• Red Hat Enterprise Linux Server 7.4 update for kernel
• Red Hat update for kernel
• Security restrictions bypass in F5 BIG-IP (Linux kernel component)
• Security restrictions bypass in F5 BIG-IQ Centralized Management (Linux kernel component)
• Security restrictions bypass in F5OS (Linux kernel component)
• Security restrictions bypass in F5 BIG-IP SPK (Linux kernel component)