CVE-2017-18344

Published: 26 July 2018

The timer_create syscall implementation in kernel/time/posix-timers.c in the Linux kernel before 4.14.8 doesn't properly validate the sigevent->sigev_notify field, which leads to out-of-bounds access in the show_timer function (called when /proc/$PID/timers is read). This allows userspace applications to read arbitrary kernel memory (on a kernel built with CONFIG_POSIX_TIMERS and CONFIG_CHECKPOINT_RESTORE).

From the Ubuntu Security Team

Andrey Konovalov discovered an out-of-bounds read in the POSIX timers subsystem in the Linux kernel. A local attacker could use this to cause a denial of service (system crash) or expose sensitive information.

Status

Severity score breakdown

References

• https://cdn.kernel.org/pub/linux/kernel/v4.x/ChangeLog-4.14.8
• https://github.com/torvalds/linux/commit/cef31d9af908243421258f1df35a4a644604efbe
• http://www.openwall.com/lists/oss-security/2018/08/09/6
• https://ubuntu.com/security/notices/USN-3742-1
• https://ubuntu.com/security/notices/USN-3742-2
• https://www.cve.org/CVERecord?id=CVE-2017-18344
• NVD
• Launchpad
• Debian