Microsoft Malware Protection Engine up to 1.1.13804.0 on 32-bit mpengine.dll access control

CVSS Meta Temp Score CVSS is a standardized scoring system to determine possibilities of attacks. The Temp Score considers temporal factors like disclosure, exploit and countermeasures. The unique Meta Score calculates the average score of different sources to provide a normalized scoring system.	Current Exploit Price (≈) Our analysts are monitoring exploit markets and are in contact with vulnerability brokers. The range indicates the observed or calculated exploit price to be seen on exploit markets. A good indicator to understand the monetary effort required for and the popularity of an attack.	CTI Interest Score Our Cyber Threat Intelligence team is monitoring different web sites, mailing lists, exploit markets and social media networks. The CTI Interest Score identifies the interest of attackers and the security community for this specific vulnerability in real-time. A high score indicates an elevated risk to be targeted for this vulnerability.
7.9	$0-$5k	0.00

A vulnerability, which was classified as very critical, was found in Microsoft Malware Protection Engine up to 1.1.13804.0 on 32-bit (Anti-Malware Software). This affects some unknown functionality in the library mpengine.dll. The manipulation with an unknown input leads to a access control vulnerability. CWE is classifying the issue as CWE-284. The product does not restrict or incorrectly restricts access to a resource from an unauthorized actor. This is going to have an impact on confidentiality, integrity, and availability.

The bug was discovered 06/23/2017. The weakness was presented 06/23/2017 by Tavis Ormandy with Google as confirmed security update guide (Website). It is possible to read the advisory at portal.msrc.microsoft.com. The public release was coordinated in cooperation with Microsoft. This vulnerability is uniquely identified as CVE-2017-8558 since 05/03/2017. It is possible to initiate the attack remotely. No form of authentication is needed for exploitation. Technical details and a public exploit are known. The pricing for an exploit might be around USD $0-$5k at the moment (estimation calculated on 12/29/2020). The attack technique deployed by this issue is T1068 according to MITRE ATT&CK. The advisory points out:

A remote code execution vulnerability exists when the Microsoft Malware Protection Engine does not properly scan a specially crafted file, leading to memory corruption. An attacker who successfully exploited this vulnerability could execute arbitrary code in the security context of the LocalSystem account and take control of the system. An attacker could then install programs; view, change, or delete data; or create new accounts with full user rights.

A public exploit has been developed by Tavis Ormandy in C and been published 4 days after the advisory. The exploit is shared for download at bugs.chromium.org. It is declared as proof-of-concept. We expect the 0-day to have been worth approximately $25k-$100k. The vulnerability scanner Nessus provides a plugin with the ID 101027 (Microsoft Malware Protection Engine < 1.1.13903 RCE), which helps to determine the existence of the flaw in a target environment. It is assigned to the family Windows and running in the context l. The code used by the exploit is:

MpApiCall("NTDLL.DLL", "VFS_Write", 1, Buf, 0, 0xffffffff, 0);
MpApiCall("NTDLL.DLL", "VFS_Write", 1, Buf, 0x7ff, 0x41414141, 0);

The advisory illustrates:

To exploit this vulnerability, a specially crafted file must be scanned by an affected version of the Microsoft Malware Protection Engine. There are many ways that an attacker could place a specially crafted file in a location that is scanned by the Microsoft Malware Protection Engine. For example, an attacker could use a website to deliver a specially crafted file to the victim's system that is scanned when the website is viewed by the user. An attacker could also deliver a specially crafted file via an email message or in an Instant Messenger message that is scanned when the file is opened. In addition, an attacker could take advantage of websites that accept or host user-provided content, to upload a specially crafted file to a shared location that is scanned by the Malware Protection Engine running on the hosting server.

Upgrading to version 1.1.13903.0 eliminates this vulnerability. Applying a patch is able to eliminate this problem. The bugfix is ready for download at catalog.update.microsoft.com. The best possible mitigation is suggested to be patching the affected component. A possible mitigation has been published immediately after the disclosure of the vulnerability. The security update guide contains the following remark:

The update addresses the vulnerability by correcting the manner in which the Microsoft Malware Protection Engine scans specially crafted files.

The vulnerability is also documented in the databases at Tenable (101027) and Exploit-DB (42264). Further details are available at bugs.chromium.org.

Affected

Microsoft Endpoint Protection
Microsoft Forefront Endpoint Protection
Microsoft Forefront Endpoint Protection 2010
Microsoft Windows Intune Endpoint Protection
Microsoft Windows Defender

Productinfo

Type

Anti-Malware Software

Vendor

Microsoft

Name

Malware Protection Engine

Version

1.1.13804

License

commercial

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB CVSS-B Score: 🔍
VulDB CVSS-BT Score: 🔍
VulDB Vector: 🔍
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 8.8
VulDB Meta Temp Score: 8.3

VulDB Base Score: 9.8
VulDB Temp Score: 8.8
VulDB Vector: 🔍
VulDB Reliability: 🔍

NVD Base Score: 7.8
NVD Vector: 🔍

CVSSv2info

AV	AC	Au	C	I	A
💳	💳	💳	💳	💳	💳
💳	💳	💳	💳	💳	💳
💳	💳	💳	💳	💳	💳

Vector	Complexity	Authentication	Confidentiality	Integrity	Availability
unlock	unlock	unlock	unlock	unlock	unlock
unlock	unlock	unlock	unlock	unlock	unlock
unlock	unlock	unlock	unlock	unlock	unlock

VulDB Base Score: 🔍
VulDB Temp Score: 🔍
VulDB Reliability: 🔍

NVD Base Score: 🔍

Exploitinginfo

Class: Access control
CWE: CWE-284 / CWE-266
ATT&CK: T1068

Local: No
Remote: Yes

Availability: 🔍
Access: Public
Status: Proof-of-Concept
Author: Tavis Ormandy
Programming Language: 🔍
Download: 🔍

EPSS Score: 🔍
EPSS Percentile: 🔍

Price Prediction: 🔍
Current Price Estimation: 🔍

0-Day	unlock	unlock	unlock	unlock
Today	unlock	unlock	unlock	unlock

Nessus ID: 101027
Nessus Name: Microsoft Malware Protection Engine < 1.1.13903 RCE
Nessus File: 🔍
Nessus Risk: 🔍
Nessus Family: 🔍
Nessus Context: 🔍

OpenVAS ID: 800442
OpenVAS Name: Microsoft Malware Protection Engine Remote Code Execution Vulnerability Jul17
OpenVAS File: 🔍
OpenVAS Family: 🔍

Exploit-DB: 🔍

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Patch
Status: 🔍

Reaction Time: 🔍
0-Day Time: 🔍
Exposure Time: 🔍
Exploit Delay Time: 🔍

Upgrade: Malware Protection Engine 1.1.13903.0
Patch: catalog.update.microsoft.com

Timelineinfo

05/03/2017 🔍
06/23/2017 +51 days 🔍
06/23/2017 +0 days 🔍
06/23/2017 +0 days 🔍
06/23/2017 +0 days 🔍
06/23/2017 +0 days 🔍
06/23/2017 +0 days 🔍
06/24/2017 +1 days 🔍
06/27/2017 +3 days 🔍
06/27/2017 +0 days 🔍
06/29/2017 +2 days 🔍
12/29/2020 +1279 days 🔍

Sourcesinfo

Vendor: microsoft.com

Advisory: portal.msrc.microsoft.com
Researcher: Tavis Ormandy
Organization: Google
Status: Confirmed
Confirmation: 🔍
Coordinated: 🔍

CVE: CVE-2017-8558 (🔍)
OVAL: 🔍

SecurityTracker: 1038783
SecurityFocus: 99262 - Microsoft Malware Protection Engine CVE-2017-8558 Remote Code Execution Vulnerability

scip Labs: https://www.scip.ch/en/?labs.20161013
Misc.: 🔍

Entryinfo

Created: 06/24/2017 08:55
Updated: 12/29/2020 16:31
Changes: 06/24/2017 08:55 (98), 10/25/2019 17:46 (5), 12/29/2020 16:31 (3)
Complete: 🔍

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