CVE-2018-1000204

MEDIUM

Description

** DISPUTED ** Linux Kernel version 3.18 to 4.16 incorrectly handles an SG_IO ioctl on /dev/sg0 with dxfer_direction=SG_DXFER_FROM_DEV and an empty 6-byte cmdp. This may lead to copying up to 1000 kernel heap pages to the userspace. This has been fixed upstream in https://github.com/torvalds/linux/commit/a45b599ad808c3c982fdcdc12b0b8611c2f92824 already. The problem has limited scope, as users don't usually have permissions to access SCSI devices. On the other hand, e.g. the Nero user manual suggests doing `chmod o+r+w /dev/sg*` to make the devices accessible. NOTE: third parties dispute the relevance of this report, noting that the requirement for an attacker to have both the CAP_SYS_ADMIN and CAP_SYS_RAWIO capabilities makes it "virtually impossible to exploit."

References

http://www.openwall.com/lists/oss-security/2018/06/26/3

https://access.redhat.com/errata/RHSA-2018:2948

https://github.com/torvalds/linux/commit/a45b599ad808c3c982fdcdc12b0b8611c2f92824

https://lists.debian.org/debian-lts-announce/2018/07/msg00015.html

https://lists.debian.org/debian-lts-announce/2018/07/msg00016.html

https://lists.debian.org/debian-lts-announce/2018/07/msg00020.html

https://usn.ubuntu.com/3696-1/

https://usn.ubuntu.com/3696-2/

https://usn.ubuntu.com/3752-1/

https://usn.ubuntu.com/3752-2/

https://usn.ubuntu.com/3752-3/

https://usn.ubuntu.com/3754-1/

Details

Source: MITRE

Published: 2018-06-26

Modified: 2018-10-31

Type: CWE-264

Risk Information

CVSS v2.0

Base Score: 6.3

Vector: AV:N/AC:M/Au:S/C:C/I:N/A:N

Impact Score: 6.9

Exploitability Score: 6.8

Severity: MEDIUM

CVSS v3.0

Base Score: 5.3

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

Impact Score: 3.6

Exploitability Score: 1.6

Severity: MEDIUM