CVE-2018-18281

MEDIUM

Description

Since Linux kernel version 3.2, the mremap() syscall performs TLB flushes after dropping pagetable locks. If a syscall such as ftruncate() removes entries from the pagetables of a task that is in the middle of mremap(), a stale TLB entry can remain for a short time that permits access to a physical page after it has been released back to the page allocator and reused. This is fixed in the following kernel versions: 4.9.135, 4.14.78, 4.18.16, 4.19.

References

http://packetstormsecurity.com/files/150001/Linux-mremap-TLB-Flush-Too-Late.html

http://www.openwall.com/lists/oss-security/2018/10/29/5

http://www.securityfocus.com/bid/105761

http://www.securityfocus.com/bid/106503

https://access.redhat.com/errata/RHSA-2019:0831

https://access.redhat.com/errata/RHSA-2019:2029

https://access.redhat.com/errata/RHSA-2019:2043

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

https://lists.debian.org/debian-lts-announce/2019/03/msg00017.html

https://lists.debian.org/debian-lts-announce/2019/03/msg00034.html

https://lists.debian.org/debian-lts-announce/2019/04/msg00004.html

https://usn.ubuntu.com/3832-1/

https://usn.ubuntu.com/3835-1/

https://usn.ubuntu.com/3871-1/

https://usn.ubuntu.com/3871-3/

https://usn.ubuntu.com/3871-4/

https://usn.ubuntu.com/3871-5/

https://usn.ubuntu.com/3880-1/

https://usn.ubuntu.com/3880-2/

Details

Source: MITRE

Published: 2018-10-30

Updated: 2019-04-23

Type: CWE-20

Risk Information

CVSS v2.0

Base Score: 4.6

Vector: AV:L/AC:L/Au:N/C:P/I:P/A:P

Impact Score: 6.4

Exploitability Score: 3.9

Severity: MEDIUM

CVSS v3.0

Base Score: 7.8

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

Impact Score: 5.9

Exploitability Score: 1.8

Severity: HIGH