Vulnerability identifier: #VU15643
Vulnerability risk: Low
CVSSv3.1: 3.9 [CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N/E:U/RL:O/RC:C]
CVE-ID:
CWE-ID:
CWE-284
Exploitation vector: Local
Exploit availability: No
Vulnerable software:
Linux kernel
Operating systems & Components /
Operating system
Vendor: Linux Foundation
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.
Mitigation
Install updates from vendor's website.
Vulnerable software versions
Linux kernel: 4.18 - 4.18.15, 4.14 - 4.14.77, 4.9.1 - 4.9.134
External links
http://packetstormsecurity.com/files/150001/Linux-mremap-TLB-Flush-Too-Late.html
http://www.openwall.com/lists/oss-security/2018/10/29/5
http://bugs.chromium.org/p/project-zero/issues/detail?id=1695
http://cdn.kernel.org/pub/linux/kernel/v4.x/ChangeLog-4.14.78
http://cdn.kernel.org/pub/linux/kernel/v4.x/ChangeLog-4.18.16
http://cdn.kernel.org/pub/linux/kernel/v4.x/ChangeLog-4.9.135
http://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=eb66ae030829605d61fbef1909ce310e29f78821
Can this vulnerability be exploited remotely?
No. This vulnerability can be exploited locally. The attacker should have authentication credentials and successfully authenticate on the system.
Is there known malware, which exploits this vulnerability?
No. We are not aware of malware exploiting this vulnerability.