Improper access control in Linux kernel - CVE-2018-18281
Published: October 31, 2018
Vulnerability identifier: #VU15643
CSH Severity: Low
CVSS v4.0: 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/E:U/U:Clear
CVE-ID: CVE-2018-18281
CWE-ID: CWE-284
Exploitation vector: Local access
Exploit availability:
No public exploit available
Vendor: Linux Foundation
Affected software:
Linux kernel
Linux kernel
Detailed vulnerability description
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.
How to mitigate CVE-2018-18281
Install updates from vendor's website.
Sources
- 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