FreeBSD VuXML: Documenting security issues in FreeBSD and the FreeBSD Ports Collection

FreeBSD -- Mishandling of x86 debug exceptions

Affected packages
11.1 <= FreeBSD-kernel < 11.1_10
10.4 <= FreeBSD-kernel < 10.4_9

Details

VuXML ID 521ce804-52fd-11e8-9123-a4badb2f4699
Discovery 2018-05-08
Entry 2018-05-08

Problem Description:

The MOV SS and POP SS instructions inhibit debug exceptions until the instruction boundary following the next instruction. If that instruction is a system call or similar instruction that transfers control to the operating system, the debug exception will be handled in the kernel context instead of the user context.

Impact:

An authenticated local attacker may be able to read sensitive data in kernel memory, control low-level operating system functions, or may panic the system.

References

CVE Name CVE-2018-8897
FreeBSD Advisory SA-18:06.debugreg