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CVE-2018-8897

UnknownEPSS 18.40%

Last modified

CVE-2018-8897 is a vulnerability of currently unknown severity. 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. EPSS estimates a 18.40% chance of exploitation in the next 30 days.

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.

Metrics

EPSS Probability
18.40%

96.9th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

VendorProductVersions
DebianDebian Linux7.0
DebianDebian Linux8.0
DebianDebian Linux9.0
CanonicalUbuntu Linux14.04
CanonicalUbuntu Linux16.04
CanonicalUbuntu Linux17.10
RedhatEnterprise Linux Server7.0
RedhatEnterprise Linux Workstation7.0
RedhatEnterprise Virtualization Manager3.0
CitrixXenserver6.0.2
CitrixXenserver6.2.0
CitrixXenserver6.5
CitrixXenserver7.0
CitrixXenserver7.1
CitrixXenserver7.2
CitrixXenserver7.3
CitrixXenserver7.4
SynologySkynasAll versions
SynologyDiskstation Manager5.2
SynologyDiskstation Manager6.0
SynologyDiskstation Manager6.1
AppleMac Os X< 10.13.4
XenXenAll versions
FreebsdFreebsd>= 11.0, < 11.1

References

Timeline

Published
Last Modified
Status
Modified

Frequently Asked Questions

What is CVE-2018-8897?
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.
How severe is CVE-2018-8897?
Severity scoring for CVE-2018-8897 is pending analysis. The EPSS model estimates a 18.40% probability of exploitation in the next 30 days.
How do I fix CVE-2018-8897?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

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Source: NVD / NIST