CVE-2018-8126 — Internet Explorer Security Feature Bypass Vulnerability

Executive Summary

A security feature bypass vulnerability exists when Internet Explorer fails to validate User Mode Code Integrity (UMCI) policies. The vulnerability could allow an attacker to bypass Device Guard UMCI policies. To exploit the vulnerability, a user could either visit a malicious website or an attacker with access to the system could run a specially crafted application. An attacker could then leverage the vulnerability to run unsigned malicious code as though it were signed by a trusted source. The update addresses the vulnerability by correcting how Internet Explorer validates UMCI policies.

Overview

5.3

CVSS MEDIUM

Important

MS Severity

Not Exploited

MS Exploit Status

Less Likely

MS Exploit Likelihood

Category Security Feature Bypass

Released May 8 2018

Last Updated May 8 2018

Publicly Disclosed No

CISA KEV Not Listed

Known Exploits None Known

CVSS Vector

ATTACK VECTOR

Local

ATTACK COMPLEXITY

Low

PRIVILEGES REQUIRED

Low

USER INTERACTION

None

SCOPE

Unchanged

CONFIDENTIALITY

Low

INTEGRITY

Low

AVAILABILITY

Low

EXPLOIT CODE MATURITY

Proof-of-Concept

REMEDIATION LEVEL

Official Fix

REPORT CONFIDENCE

Confirmed

Temporal Score: 4.8

EPSS Score

No EPSS score available for this CVE.

View on FIRST.org

Affected Products

11 affected products

Product	KB Article	Severity	Impact	Restart Required
Internet Explorer 11 on Windows 10 for 32-bit Systems	`4103716 (Security Update)`	Important	Security Feature Bypass	Yes
Internet Explorer 11 on Windows 10 for x64-based Systems	`4103716 (Security Update)`	Important	Security Feature Bypass	Yes
Internet Explorer 11 on Windows 10 Version 1607 for 32-bit Systems	`4103723 (Security Update)`	Important	Security Feature Bypass	Yes
Internet Explorer 11 on Windows 10 Version 1607 for x64-based Systems	`4103723 (Security Update)`	Important	Security Feature Bypass	Yes
Internet Explorer 11 on Windows 10 Version 1703 for 32-bit Systems	`4103731 (Security Update)`	Important	Security Feature Bypass	Yes
Internet Explorer 11 on Windows 10 Version 1703 for x64-based Systems	`4103731 (Security Update)`	Important	Security Feature Bypass	Yes
Internet Explorer 11 on Windows 10 Version 1709 for 32-bit Systems	`4103727 (Security Update)`	Important	Security Feature Bypass	Yes
Internet Explorer 11 on Windows 10 Version 1709 for x64-based Systems	`4103727 (Security Update)`	Important	Security Feature Bypass	Yes
Internet Explorer 11 on Windows 10 Version 1803 for 32-bit Systems	`4103721 (Security Update)`	Important	Security Feature Bypass	Yes
Internet Explorer 11 on Windows 10 Version 1803 for x64-based Systems	`4103721 (Security Update)`	Important	Security Feature Bypass	Yes
Internet Explorer 11 on Windows Server 2016	`4103723 (Security Update)`	Low	Security Feature Bypass	Yes

Patches

5 patches

Article	Type	Restart
`4103716`	Security Update	Yes
`4103723`	Security Update	Yes
`4103731`	Security Update	Yes
`4103727`	Security Update	Yes
`4103721`	Security Update	Yes

Known Exploits

No known exploits have been linked for this CVE yet. When available, exploit references will be sourced from public repositories and may be unverified, incomplete, or non-functional. Always review code carefully before use in any environment.

Acknowledgments

Matt Nelson ( @enigma0x3

References

MSRC Advisory MITRE NVD