Remote Desktop Services Remote Code Execution Vulnerability

CVE-2019-1181

Security Vulnerability

Released: Aug 13, 2019

Last updated: Oct 13, 2020

Assigning CNA: Microsoft

CVE.org link: CVE-2019-1181

Impact: Remote Code Execution

Max Severity: Critical

Vector String: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H/E:P/RL:O/RC:C

Metrics: CVSS:3.1 9.8 / 8.8

Metric

Value

Base score metrics(8)

Attack Vector

This metric reflects the context by which vulnerability exploitation is possible. The Base Score increases the more remote (logically, and physically) an attacker can be in order to exploit the vulnerable component.

Network

The vulnerable component is bound to the network stack and the set of possible attackers extends beyond the other options listed, up to and including the entire Internet. Such a vulnerability is often termed 'remotely exploitable' and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).

Attack Complexity

This metric describes the conditions beyond the attacker’s control that must exist in order to exploit the vulnerability. Such conditions may require the collection of more information about the target or computational exceptions. The assessment of this metric excludes any requirements for user interaction in order to exploit the vulnerability. If a specific configuration is required for an attack to succeed, the Base metrics should be scored assuming the vulnerable component is in that configuration.

Low

Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.

Privileges Required

This metric describes the level of privileges an attacker must possess before successfully exploiting the vulnerability.

None

The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files to carry out an attack.

User Interaction

This metric captures the requirement for a user, other than the attacker, to participate in the successful compromise the vulnerable component. This metric determines whether the vulnerability can be exploited solely at the will of the attacker, or whether a separate user (or user-initiated process) must participate in some manner.

None

The vulnerable system can be exploited without any interaction from any user.

Scope

Does a successful attack impact a component other than the vulnerable component? If so, the Base Score increases and the Confidentiality, Integrity and Authentication metrics should be scored relative to the impacted component.

Unchanged

An exploited vulnerability can only affect resources managed by the same security authority. In this case, the vulnerable component and the impacted component are either the same, or both are managed by the same security authority.

Confidentiality

This metric measures the impact to the confidentiality of the information resources managed by a software component due to a successfully exploited vulnerability. Confidentiality refers to limiting information access and disclosure to only authorized users, as well as preventing access by, or disclosure to, unauthorized ones.

High

There is total loss of confidentiality, resulting in all resources within the impacted component being divulged to the attacker. Alternatively, access to only some restricted information is obtained, but the disclosed information presents a direct, serious impact.

Integrity

This metric measures the impact to integrity of a successfully exploited vulnerability. Integrity refers to the trustworthiness and veracity of information.

High

There is a total loss of integrity, or a complete loss of protection. For example, the attacker is able to modify any/all files protected by the impacted component. Alternatively, only some files can be modified, but malicious modification would present a direct, serious consequence to the impacted component.

Availability

This metric measures the impact to the availability of the impacted component resulting from a successfully exploited vulnerability. It refers to the loss of availability of the impacted component itself, such as a networked service (e.g., web, database, email). Since availability refers to the accessibility of information resources, attacks that consume network bandwidth, processor cycles, or disk space all impact the availability of an impacted component.

High

There is total loss of availability, resulting in the attacker being able to fully deny access to resources in the impacted component; this loss is either sustained (while the attacker continues to deliver the attack) or persistent (the condition persists even after the attack has completed). Alternatively, the attacker has the ability to deny some availability, but the loss of availability presents a direct, serious consequence to the impacted component (e.g., the attacker cannot disrupt existing connections, but can prevent new connections; the attacker can repeatedly exploit a vulnerability that, in each instance of a successful attack, leaks a only small amount of memory, but after repeated exploitation causes a service to become completely unavailable).

Temporal score metrics(3)

Exploit Code Maturity

This metric measures the likelihood of the vulnerability being attacked, and is typically based on the current state of exploit techniques, public availability of exploit code, or active, 'in-the-wild' exploitation.

Proof-of-Concept

Proof-of-concept exploit code is available, or an attack demonstration is not practical for most systems. The code or technique is not functional in all situations and may require substantial modification by a skilled attacker.

Remediation Level

The Remediation Level of a vulnerability is an important factor for prioritization. The typical vulnerability is unpatched when initially published. Workarounds or hotfixes may offer interim remediation until an official patch or upgrade is issued. Each of these respective stages adjusts the temporal score downwards, reflecting the decreasing urgency as remediation becomes final.

Official Fix

A complete vendor solution is available. Either the vendor has issued an official patch, or an upgrade is available.

Report Confidence

This metric measures the degree of confidence in the existence of the vulnerability and the credibility of the known technical details. Sometimes only the existence of vulnerabilities are publicized, but without specific details. For example, an impact may be recognized as undesirable, but the root cause may not be known. The vulnerability may later be corroborated by research which suggests where the vulnerability may lie, though the research may not be certain. Finally, a vulnerability may be confirmed through acknowledgement by the author or vendor of the affected technology. The urgency of a vulnerability is higher when a vulnerability is known to exist with certainty. This metric also suggests the level of technical knowledge available to would-be attackers.

Confirmed

Detailed reports exist, or functional reproduction is possible (functional exploits may provide this). Source code is available to independently verify the assertions of the research, or the author or vendor of the affected code has confirmed the presence of the vulnerability.

Please see Common Vulnerability Scoring System for more information on the definition of these metrics.

Executive Summary

A remote code execution vulnerability exists in Remote Desktop Services – formerly known as Terminal Services – when an unauthenticated attacker connects to the target system using RDP and sends specially crafted requests. This vulnerability is pre-authentication and requires no user interaction. An attacker who successfully exploited this vulnerability could execute arbitrary code on the target system. An attacker could then install programs; view, change, or delete data; or create new accounts with full user rights.

To exploit this vulnerability, an attacker would need to send a specially crafted request to the target systems Remote Desktop Service via RDP.

The update addresses the vulnerability by correcting how Remote Desktop Services handles connection requests.

Exploitability

The following table provides an exploitability assessment for this vulnerability at the time of original publication.

Publicly disclosed: No
Exploited: No
Exploitability assessment: Exploitation More Likely

Mitigations

The following mitigation may be helpful in your situation. In all cases, Microsoft strongly recommends that you install the updates for this vulnerability as soon as possible even if you plan to leave Remote Desktop Services disabled:

1. Disable Remote Desktop Services if they are not required.

If you no longer need these services on your system, consider disabling them as a security best practice. Disabling unused and unneeded services helps reduce your exposure to security vulnerabilities.

Workarounds

The following workaround may be helpful in your situation. In all cases, Microsoft strongly recommends that you install the updates for this vulnerability as soon as possible even if you plan to leave these workarounds in place:

1. Enable Network Level Authentication (NLA)

You can enable Network Level Authentication to block unauthenticated attackers from exploiting this vulnerability. With NLA turned on, an attacker would first need to authenticate to Remote Desktop Services using a valid account on the target system before the attacker could exploit the vulnerability.

2. Block TCP port 3389 at the enterprise perimeter firewall

TCP port 3389 is used to initiate a connection with the affected component. Blocking this port at the network perimeter firewall will help protect systems that are behind that firewall from attempts to exploit this vulnerability. This can help protect networks from attacks that originate outside the enterprise perimeter. Blocking the affected ports at the enterprise perimeter is the best defense to help avoid Internet-based attacks. However, systems could still be vulnerable to attacks from within their enterprise perimeter.

FAQ

How do I get the update for Microsoft Remote Desktop for IOS?

Tap the Settings Icon
Tap the iTunes & App Store
Turn on AUTOMATIC DOWNLOADS for Apps

Alternatively

Tap the App Store Icon
Scroll down to find Microsoft Remote Desktop
Tap the Update button

I am running Windows 7 Service Pack 1 or Windows Server 2008 R2 Service Pack 1. Is there more information of which I need to be aware?

These operating systems are only affected by this vulnerability if either RDP 8.0 or RDP 8.1 is installed. If you do not have either of these versions of RDP installed on Windows 7 SP1 or Window Server 2008 R2 SP1, then you are not affected by this vulnerability.

How do I get the update for Microsoft Remote Desktop for Android?

Tap the Google Play icon on your home screen.
Swipe in from the left edge of the screen.
Tap My apps & games.
Tap the Update box next to the Remote Desktop app.

How do I get the update for Microsoft Remote Desktop for Mac?

Open the Mac app store.
Search for Microsoft Remote Desktop.
Download the update. Version 10.4.1 contains the security update that addresses this vulnerability.

Acknowledgements

Andrew Burkhardt of MSRC Vulnerabilities & Mitigations Team
Microsoft Platform Security Assurance & Vulnerability Research

Microsoft recognizes the efforts of those in the security community who help us protect customers through coordinated vulnerability disclosure. See Acknowledgements for more information.

Security Updates

To determine the support lifecycle for your software, see the Microsoft Support Lifecycle.

Release date Descending

Release date

Product

Platform

Impact

Max Severity

Article

Download

Build Number

Aug 13, 2019

Windows Server 2012 R2 (Server Core installation)

Remote Code Execution

Critical

Aug 13, 2019

Windows Server 2012 R2

Remote Code Execution

Critical

Aug 13, 2019

Windows Server 2012 (Server Core installation)

Remote Code Execution

Critical

Aug 13, 2019

Windows Server 2012

Remote Code Execution

Critical

Aug 13, 2019

Windows RT 8.1

Remote Code Execution

Critical

4512488

Monthly Rollup

Aug 13, 2019

Microsoft Remote Desktop for Mac

Remote Code Execution

Critical

Release Notes

Security Update

Aug 13, 2019

Microsoft Remote Desktop for IoS

Remote Code Execution

Critical

Release Notes

Security Update

Aug 13, 2019

Microsoft Remote Desktop for Android

Remote Code Execution

Critical

Release Notes

Security Update

Aug 13, 2019

Windows 8.1 for x64-based systems

Remote Code Execution

Critical

Aug 13, 2019

Windows 8.1 for 32-bit systems

Remote Code Execution

Critical

Aug 13, 2019

Windows Server 2016 (Server Core installation)

Remote Code Execution

Critical

4512517

Security Update

Aug 13, 2019

Windows Server 2016

Remote Code Execution

Critical

4512517

Security Update

Aug 13, 2019

Windows 10 Version 1607 for x64-based Systems

Remote Code Execution

Critical

4512517

Security Update

Aug 13, 2019

Windows 10 Version 1607 for 32-bit Systems

Remote Code Execution

Critical

4512517

Security Update

Aug 13, 2019

Windows 10 for x64-based Systems

Remote Code Execution

Critical

4512497

Security Update

Aug 13, 2019

Windows 10 for 32-bit Systems

Remote Code Execution

Critical

4512497

Security Update

Aug 13, 2019

Windows Server, version 1903 (Server Core installation)

Remote Code Execution

Critical

4512508

Security Update

Aug 13, 2019

Windows 10 Version 1903 for ARM64-based Systems

Remote Code Execution

Critical

4512508

Security Update

Aug 13, 2019

Windows 10 Version 1903 for x64-based Systems

Remote Code Execution

Critical

4512508

Security Update

Aug 13, 2019

Windows 10 Version 1903 for 32-bit Systems

Remote Code Execution

Critical

4512508

Security Update

Aug 13, 2019

Windows 10 Version 1709 for ARM64-based Systems

Remote Code Execution

Critical

4512516

Security Update

Aug 13, 2019

Windows 10 Version 1709 for x64-based Systems

Remote Code Execution

Critical

4512516

Security Update

Aug 13, 2019

Windows 10 Version 1709 for 32-bit Systems

Remote Code Execution

Critical

4512516

Security Update

Aug 13, 2019

Windows Server 2019 (Server Core installation)

Remote Code Execution

Critical

4511553

Security Update

Aug 13, 2019

Windows Server 2019

Remote Code Execution

Critical

4511553

Security Update

Aug 13, 2019

Windows 10 Version 1809 for ARM64-based Systems

Remote Code Execution

Critical

4511553

Security Update

Aug 13, 2019

Windows 10 Version 1809 for x64-based Systems

Remote Code Execution

Critical

4511553

Security Update

Aug 13, 2019

Windows 10 Version 1809 for 32-bit Systems

Remote Code Execution

Critical

4511553

Security Update

Aug 13, 2019

Windows 10 Version 1803 for ARM64-based Systems

Remote Code Execution

Critical

4512501

Security Update

Aug 13, 2019

Windows Server, version 1803 (Server Core Installation)

Remote Code Execution

Critical

4512501

Security Update

Aug 13, 2019

Windows 10 Version 1803 for x64-based Systems

Remote Code Execution

Critical

4512501

Security Update

Aug 13, 2019

Windows 10 Version 1803 for 32-bit Systems

Remote Code Execution

Critical

4512501

Security Update

Aug 13, 2019

Windows 10 Version 1703 for x64-based Systems

Remote Code Execution

Critical

4512507

Security Update

Aug 13, 2019

Windows 10 Version 1703 for 32-bit Systems

Remote Code Execution

Critical

4512507

Security Update

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Disclaimer

The information provided in the Microsoft Knowledge Base is provided "as is" without warranty of any kind. Microsoft disclaims all warranties, either express or implied, including the warranties of merchantability and fitness for a particular purpose. In no event shall Microsoft Corporation or its suppliers be liable for any damages whatsoever including direct, indirect, incidental, consequential, loss of business profits or special damages, even if Microsoft Corporation or its suppliers have been advised of the possibility of such damages. Some states do not allow the exclusion or limitation of liability for consequential or incidental damages so the foregoing limitation may not apply.

Revisions

version

revisionDate

description

2.0

Oct 13, 2020

Revised the Security Updates table to add Microsoft Remote Desktop for Android, Microsoft Remote Desktop for Mac, and Microsoft Remote Desktop for Mac IoS because these apps are affected by this vulnerability. Microsoft recommends that customers running any of these apps install the latest security update to be fully protected from this vulnerability. Please see the FAQ section for information on how to get these updates.

1.0

Aug 13, 2019

Information published.

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