Detections
Analytics
CVE-2018-8897
high
Description
A statement in the System Programming Guide of the Intel 64 and IA-32 Architectures Software Developer's Manual (SDM) was mishandled in the development of some or all operating-system kernels, resulting in unexpected behavior for #DB exceptions that are deferred by MOV SS or POP SS, as demonstrated by (for example) privilege escalation in Windows, macOS, some Xen configurations, or FreeBSD, or a Linux kernel crash. The MOV to SS and POP SS instructions inhibit interrupts (including NMIs), data breakpoints, and single step trap exceptions until the instruction boundary following the next instruction (SDM Vol. 3A; section 6.8.3). (The inhibited data breakpoints are those on memory accessed by the MOV to SS or POP to SS instruction itself.) Note that debug exceptions are not inhibited by the interrupt enable (EFLAGS.IF) system flag (SDM Vol. 3A; section 2.3). If the instruction following the MOV to SS or POP to SS instruction is an instruction like SYSCALL, SYSENTER, INT 3, etc. that transfers control to the operating system at CPL < 3, the debug exception is delivered after the transfer to CPL < 3 is complete. OS kernels may not expect this order of events and may therefore experience unexpected behavior when it occurs.
References
https://xenbits.xen.org/xsa/advisory-260.html
https://www.triplefault.io/2018/05/spurious-db-exceptions-with-pop-ss.html
https://www.synology.com/support/security/Synology_SA_18_21
https://www.kb.cert.org/vuls/id/631579
https://www.freebsd.org/security/advisories/FreeBSD-SA-18:06.debugreg.asc
https://www.exploit-db.com/exploits/45024/
https://www.debian.org/security/2018/dsa-4201
https://www.debian.org/security/2018/dsa-4196
https://usn.ubuntu.com/3641-2/
https://usn.ubuntu.com/3641-1/
https://svnweb.freebsd.org/base?view=revision&revision=333368
https://support.citrix.com/article/CTX234679
https://support.apple.com/HT208742
https://security.netapp.com/advisory/ntap-20180927-0002/
https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2018-8897
https://patchwork.kernel.org/patch/10386677/
https://lists.debian.org/debian-lts-announce/2018/11/msg00013.html
https://lists.debian.org/debian-lts-announce/2018/06/msg00000.html
https://lists.debian.org/debian-lts-announce/2018/05/msg00015.html
https://github.com/torvalds/linux/commit/d8ba61ba58c88d5207c1ba2f7d9a2280e7d03be9
https://bugzilla.redhat.com/show_bug.cgi?id=1567074
https://access.redhat.com/errata/RHSA-2018:1524
https://access.redhat.com/errata/RHSA-2018:1355
https://access.redhat.com/errata/RHSA-2018:1354
https://access.redhat.com/errata/RHSA-2018:1353
https://access.redhat.com/errata/RHSA-2018:1352
https://access.redhat.com/errata/RHSA-2018:1351
https://access.redhat.com/errata/RHSA-2018:1350
https://access.redhat.com/errata/RHSA-2018:1349
https://access.redhat.com/errata/RHSA-2018:1348
https://access.redhat.com/errata/RHSA-2018:1347
https://access.redhat.com/errata/RHSA-2018:1346
https://access.redhat.com/errata/RHSA-2018:1345
https://access.redhat.com/errata/RHSA-2018:1319
https://access.redhat.com/errata/RHSA-2018:1318
http://www.securitytracker.com/id/1040882
http://www.securitytracker.com/id/1040866
http://www.securitytracker.com/id/1040861
http://www.securitytracker.com/id/1040849
http://www.securitytracker.com/id/1040744
http://www.securityfocus.com/bid/104071
http://www.huawei.com/en/psirt/security-advisories/huawei-sa-20190921-01-debug-en
http://openwall.com/lists/oss-security/2018/05/08/4