CVE-2018-13405 Information

Description

The inode_init_owner function in fs/inode.c in the Linux kernel through 4.17.4 allows local users to create files with an unintended group ownership in a scenario where a directory is SGID to a certain group and is writable by a user who is not a member of that group. Here the non-member can trigger creation of a plain file whose group ownership is that group. The intended behavior was that the non-member can trigger creation of a directory (but not a plain file) whose group ownership is that group. The non-member can escalate privileges by making the plain file executable and SGID.

CVSS Vector

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

Reference

http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=0fa3ecd87848c9c93c2c828ef4c3a8ca36ce46c7 http://openwall.com/lists/oss-security/2018/07/13/2 http://www.securityfocus.com/bid/106503 https://access.redhat.com/errata/RHSA-2018:2948 https://access.redhat.com/errata/RHSA-2018:3083 https://access.redhat.com/errata/RHSA-2018:3096 https://access.redhat.com/errata/RHSA-2019:0717 https://access.redhat.com/errata/RHSA-2019:2476 https://access.redhat.com/errata/RHSA-2019:2566 https://access.redhat.com/errata/RHSA-2019:2696 https://access.redhat.com/errata/RHSA-2019:2730 https://access.redhat.com/errata/RHSA-2019:4159 https://access.redhat.com/errata/RHSA-2019:4164 https://github.com/torvalds/linux/commit/0fa3ecd87848c9c93c2c828ef4c3a8ca36ce46c7 https://lists.debian.org/debian-lts-announce/2018/08/msg00014.html https://support.f5.com/csp/article/K00854051 https://twitter.com/grsecurity/status/1015082951204327425 https://usn.ubuntu.com/3752-1/ https://usn.ubuntu.com/3752-2/ https://usn.ubuntu.com/3752-3/ https://usn.ubuntu.com/3753-1/ https://usn.ubuntu.com/3753-2/ https://usn.ubuntu.com/3754-1/ https://www.debian.org/security/2018/dsa-4266 https://www.exploit-db.com/exploits/45033/

Attack Complexity

LOW

Privileges Required

LOW

User Interaction Required

LOW

Scope

NONE

Confidentiality Impact

UNCHANGED

Integrity Impact

HIGH

Availability Impact

HIGH

Base Score

HIGH

Base Severity

7.8