| Vulnerability Name: | CVE-2018-18955 (CCN-153056) | ||||||||||||||||||||||||||||||||
| Assigned: | 2018-11-05 | ||||||||||||||||||||||||||||||||
| Published: | 2018-11-05 | ||||||||||||||||||||||||||||||||
| Updated: | 2020-08-24 | ||||||||||||||||||||||||||||||||
| Summary: | In the Linux kernel 4.15.x through 4.19.x before 4.19.2, map_write() in kernel/user_namespace.c allows privilege escalation because it mishandles nested user namespaces with more than 5 UID or GID ranges. A user who has CAP_SYS_ADMIN in an affected user namespace can bypass access controls on resources outside the namespace, as demonstrated by reading /etc/shadow. This occurs because an ID transformation takes place properly for the namespaced-to-kernel direction but not for the kernel-to-namespaced direction. | ||||||||||||||||||||||||||||||||
| CVSS v3 Severity: | 7.0 High (CVSS v3.1 Vector: CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H) 6.5 Medium (Temporal CVSS v3.1 Vector: CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H/E:F/RL:O/RC:C)
7.8 High (CCN Temporal CVSS v3.1 Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H/E:F/RL:O/RC:C)
| ||||||||||||||||||||||||||||||||
| CVSS v2 Severity: | 4.4 Medium (CVSS v2 Vector: AV:L/AC:M/Au:N/C:P/I:P/A:P)
| ||||||||||||||||||||||||||||||||
| Vulnerability Type: | CWE-863 | ||||||||||||||||||||||||||||||||
| Vulnerability Consequences: | Gain Privileges | ||||||||||||||||||||||||||||||||
| References: | Source: MITRE Type: CNA CVE-2018-18955 Source: MISC Type: Patch, Vendor Advisory http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=d2f007dbe7e4c9583eea6eb04d60001e85c6f1bd Source: BID Type: Third Party Advisory, VDB Entry 105941 Source: MISC Type: Patch, Third Party Advisory https://bugs.chromium.org/p/project-zero/issues/detail?id=1712 Source: CCN Type: Google Security Research Issue 1712 Linux: broken uid/gid mapping for nested user namespaces with >5 ranges Source: CCN Type: Launchpad Bug #1801924 CVE-2018-18955: nested user namespaces with more than five extents incorrectly grant privileges over inode Source: MISC Type: Patch, Vendor Advisory https://cdn.kernel.org/pub/linux/kernel/v4.x/ChangeLog-4.18.19 Source: MISC Type: Patch, Vendor Advisory https://cdn.kernel.org/pub/linux/kernel/v4.x/ChangeLog-4.19.2 Source: XF Type: UNKNOWN linux-kernel-cve201818955-priv-esc(153056) Source: CCN Type: Linux Kernel GIT Repository userns: also map extents in the reverse map to kernel IDs Source: MISC Type: Patch, Vendor Advisory https://github.com/torvalds/linux/commit/d2f007dbe7e4c9583eea6eb04d60001e85c6f1bd Source: CCN Type: Packet Storm Security [11-16-2018] Linux Broken UID/GID Mapping Source: CCN Type: Packet Storm Security [11-28-2018] Linux Nested User Namespace idmap Limit Local Privilege Escalation Source: CCN Type: oss-sec Mailing List, Fri, 16 Nov 2018 00:38:18 +0100 Linux kernel: broken uid/gid mapping for nested user namespaces with >5 ranges (CVE-2018-18955; since 4.15; fixed in 4.18.19 and 4.19.2) Source: CONFIRM Type: UNKNOWN https://security.netapp.com/advisory/ntap-20190416-0003/ Source: CONFIRM Type: UNKNOWN https://support.f5.com/csp/article/K39103040 Source: UBUNTU Type: Third Party Advisory USN-3832-1 Source: UBUNTU Type: Third Party Advisory USN-3833-1 Source: UBUNTU Type: Third Party Advisory USN-3835-1 Source: UBUNTU Type: Third Party Advisory USN-3836-1 Source: UBUNTU Type: Third Party Advisory USN-3836-2 Source: EXPLOIT-DB Type: EXPLOIT Offensive Security Exploit Database [11-16-2018] Source: EXPLOIT-DB Type: Exploit, Patch, Third Party Advisory, VDB Entry 45886 Source: EXPLOIT-DB Type: EXPLOIT Offensive Security Exploit Database [11-29-2018] Source: EXPLOIT-DB Type: Exploit, Third Party Advisory, VDB Entry 45915 Source: CCN Type: Rapid7 Web site Linux Nested User Namespace idmap Limit Local Privilege Escalation Source: CCN Type: WhiteSource Vulnerability Database CVE-2018-18955 | ||||||||||||||||||||||||||||||||
| Vulnerable Configuration: | Configuration 1: Configuration 2: Configuration CCN 1:  Denotes that component is vulnerable | ||||||||||||||||||||||||||||||||
| Oval Definitions | |||||||||||||||||||||||||||||||||
| |||||||||||||||||||||||||||||||||
| BACK | |||||||||||||||||||||||||||||||||