SB2018103107 - Security restrictions bypass in Linux Kernel
Published: October 31, 2018
Breakdown by Severity
- Low
- Medium
- High
- Critical
Description
This security bulletin contains information about 1 security vulnerability.
1) Improper access control (CVE-ID: CVE-2018-18281)
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.
Remediation
Install update from vendor's website.
References
- 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