CVE-2018-0878 — Windows Remote Assistance Information Disclosure Vulnerability

Executive Summary

An information disclosure vulnerability exists when Windows Remote Assistance incorrectly processes XML External Entities (XXE). An attacker who successfully exploited the vulnerability could obtain information to further compromise the user’s system. To exploit this condition, an attacker would need to send a specially crafted Remote Assistance invitation file to a user. A attacker could then steal text files from known locations on the victim's machine, under the context of the user, or alternatively, steal text information from URLs accessible to the victim. The stolen information could be submitted as part of the URL in HTTP request(s) to the attacker. In all cases an attacker would have no way to force a user to view the attacker-controlled content. Instead, an attacker would have to convince a user to take action. Note that the information disclosure vulnerability by itself would not be sufficient for an attacker to compromise a system. However, an attacker could combine this vulnerability with additional vulnerabilities to further exploit the system. The update addresses the vulnerability by correcting how Windows Remote Assistance processes XML External Entities (XXE).

Overview

3.1

CVSS LOW

Important

MS Severity

Not Exploited

MS Exploit Status

Less Likely

MS Exploit Likelihood

Category Information Disclosure

Released Mar 13 2018

Last Updated Mar 13 2018

Publicly Disclosed No

CISA KEV Not Listed

Known Exploits None Known

CVSS Vector

ATTACK VECTOR

Network

ATTACK COMPLEXITY

High

PRIVILEGES REQUIRED

None

USER INTERACTION

Required

SCOPE

Unchanged

CONFIDENTIALITY

Low

INTEGRITY

None

AVAILABILITY

None

EXPLOIT CODE MATURITY

Proof-of-Concept

REMEDIATION LEVEL

Official Fix

REPORT CONFIDENCE

Confirmed

Temporal Score: 2.8

EPSS Score

No EPSS score available for this CVE.

View on FIRST.org

Affected Products

18 affected products

Product	KB Article	Severity	Impact	Restart Required
Windows 10 for 32-bit Systems	`4088786 (Security Update)`	Important	Information Disclosure	Yes
Windows 10 for x64-based Systems	`4088786 (Security Update)`	Important	Information Disclosure	Yes
Windows 10 Version 1511 for 32-bit Systems	`4088779 (Security Update)`	Important	Information Disclosure	Yes
Windows 10 Version 1511 for x64-based Systems	`4088779 (Security Update)`	Important	Information Disclosure	Yes
Windows 10 Version 1607 for 32-bit Systems	`4088787 (Security Update)`	Important	Information Disclosure	Yes
Windows 10 Version 1607 for x64-based Systems	`4088787 (Security Update)`	Important	Information Disclosure	Yes
Windows 10 Version 1703 for 32-bit Systems	`4088782 (Security Update)`	Important	Information Disclosure	Yes
Windows 10 Version 1703 for x64-based Systems	`4088782 (Security Update)`	Important	Information Disclosure	Yes
Windows 10 Version 1709 for 32-bit Systems	`4088776 (Security Update)`	Important	Information Disclosure	Yes
Windows 10 Version 1709 for x64-based Systems	`4088776 (Security Update)`	Important	Information Disclosure	Yes
Windows 7 for 32-bit Systems Service Pack 1 4088875 (Monthly Rollup) 4088878 (Security Only) Important Information Disclosure 4074598 Base: 3.1 Temporal: 2.8 Vector: CVSS:3.0/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:N/A:N/E:P/RL:O/RC:C Yes None Windows 7 for x64-based Systems Service Pack 1 4088875 (Monthly Rollup) 4088878 (Security Only) Important Information Disclosure 4074598 Base: 3.1 Temporal: 2.8 Vector: CVSS:3.0/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:N/A:N/E:P/RL:O/RC:C Yes None Windows 8.1 for 32-bit systems 4088876 (Monthly Rollup) 4088879 (Security Only) Important Information Disclosure 4074594 Base: 3.1 Temporal: 2.8 Vector: CVSS:3.0/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:N/A:N/E:P/RL:O/RC:C Yes None Windows 8.1 for x64-based systems 4088876 (Monthly Rollup) 4088879 (Security Only) Important Information Disclosure 4074594 Base: 3.1 Temporal: 2.8 Vector: CVSS:3.0/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:N/A:N/E:P/RL:O/RC:C Yes None Windows RT 8.1	`4088876 (Monthly Rollup)`	Important	Information Disclosure	Yes
Windows Server 2008 for 32-bit Systems Service Pack 2	`4089453 (Security Update)`	Important	Information Disclosure	Yes
Windows Server 2008 for 32-bit Systems Service Pack 2 (Server Core installation)	`4089453 (Security Update)`	Important	Information Disclosure	Yes
Windows Server 2008 for x64-based Systems Service Pack 2	`4089453 (Security Update)`	Important	Information Disclosure	Yes
Windows Server 2008 for x64-based Systems Service Pack 2 (Server Core installation)	`4089453 (Security Update)`	Important	Information Disclosure	Yes
Windows Server 2008 R2 for x64-based Systems Service Pack 1 4088875 (Monthly Rollup) 4088878 (Security Only) Important Information Disclosure 4074598 Base: 3.1 Temporal: 2.8 Vector: CVSS:3.0/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:N/A:N/E:P/RL:O/RC:C Yes None Windows Server 2008 R2 for x64-based Systems Service Pack 1 (Server Core installation) 4088875 (Monthly Rollup) 4088878 (Security Only) Important Information Disclosure 4074598 Base: 3.1 Temporal: 2.8 Vector: CVSS:3.0/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:N/A:N/E:P/RL:O/RC:C Yes None Windows Server 2012 4088877 (Monthly Rollup) 4088880 (Security Only) Important Information Disclosure 4074593 Base: 3.1 Temporal: 2.8 Vector: CVSS:3.0/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:N/A:N/E:P/RL:O/RC:C Yes None Windows Server 2012 (Server Core installation) 4088877 (Monthly Rollup) 4088880 (Security Only) Important Information Disclosure 4074593 Base: 3.1 Temporal: 2.8 Vector: CVSS:3.0/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:N/A:N/E:P/RL:O/RC:C Yes None Windows Server 2012 R2 4088876 (Monthly Rollup) 4088879 (Security Only) Important Information Disclosure 4074594 Base: 3.1 Temporal: 2.8 Vector: CVSS:3.0/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:N/A:N/E:P/RL:O/RC:C Yes None Windows Server 2012 R2 (Server Core installation) 4088876 (Monthly Rollup) 4088879 (Security Only) Important Information Disclosure 4074594 Base: 3.1 Temporal: 2.8 Vector: CVSS:3.0/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:N/A:N/E:P/RL:O/RC:C Yes None Windows Server 2016	`4088787 (Security Update)`	Important	Information Disclosure	Yes
Windows Server 2016 (Server Core installation)	`4088787 (Security Update)`	Important	Information Disclosure	Yes
Windows Server, version 1709 (Server Core Installation)	`4088776 (Security Update)`	Important	Information Disclosure	Yes

Patches

7 patches

Article	Type	Restart
`4088786`	Security Update	Yes
`4088779`	Security Update	Yes
`4088787`	Security Update	Yes
`4088782`	Security Update	Yes
`4088776`	Security Update	Yes
`4088876`	Monthly Rollup	Yes
`4089453`	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

Abdulrahman Al-Qabandi
Nabeel Ahmed working with Trend Micro's Zero Day Initiative
Anonymous working with Trend Micro's Zero Day Initiative

References

MSRC Advisory MITRE NVD