Dark Reading is part of the Informa Tech Division of Informa PLC

This site is operated by a business or businesses owned by Informa PLC and all copyright resides with them.Informa PLC's registered office is 5 Howick Place, London SW1P 1WG. Registered in England and Wales. Number 8860726.

Vulnerabilities / Threats

5/9/2017
11:15 AM
Connect Directly
Twitter
RSS
E-Mail
50%
50%

Microsoft Releases Emergency Patch For RCE Vuln

Flaw in Microsoft Malware Protection Engine called 'crazy bad' by researchers who discovered it.

Late last night Microsoft released an emergency out-of-band patch to fix a vulnerability in Microsoft Malware Protection Engine (MsMpEng) that one of the researchers who found it called "the worst Windows remote code exec(ution) in recent memory," and for which US-CERT released an alert.

Announced over the weekend by a pair of researchers working for the Google Project Zero team, Tavis Ormandy and Natalie Silanovich, the vulnerability allows attackers to carry out remote code execution (RCE) by feeding MsMpEng a simple malicious file to trigger memory corruption. According to Silanovich, the vulnerability only requires a simple exploit to leverage, requiring so little code that it can fit in a single tweet. According to Microsoft Security Advisory 4022344, the affected version of the engine must scan the specially crafted file, but that can be easily achieved a number of ways.

"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," Microsoft advises. "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."

In fact, when Ormandy and Silanovich released their proof-of-concept code they warned anyone using Microsoft systems to take extra care with the file because simply downloading it could immediately crash MsMpEng in its default configuration. Given the triviality of exploit, the default-on status of MsMpEng in Windows systems from Windows 8 on up, and the permissions afforded to the service, Ormandy calls this particular hole "crazy bad."

"Vulnerabilities in MsMpEng are among the most severe possible in Windows, due to the privilege, accessibility, and ubiquity of the service," he wrote. "The core component of MsMpEng responsible for scanning and analysis is called mpengine. Mpengine is a vast and complex attack surface, comprising of handlers for dozens of esoteric archive formats, executable packers and cryptors, full system emulators and interpreters for various architectures and languages, and so on. All of this code is accessible to remote attackers."

Ormandy and Silanovich went through coordinated vulnerability disclosure procedures with Microsoft, which came up with this release within just a few days. Microsoft says that updates to the engine will be automatically installed with updated malware definitions for the affected products, such that the typical consumer end user should see the update applied within 48 hours. Consumers can speed up that timetable by manually updating their anti-malware software. Meanwhile, Microsoft advises enterprise customers to follow internal processes to confirm that their patch management software has approved and installed necessary definition and engine updates.

"Administrators of enterprise anti-malware deployments should ensure that their update management software is configured to automatically approve and distribute engine updates and new malware definitions. Enterprise administrators should also verify that the latest version of the Microsoft Malware Protection Engine and definition updates are being actively downloaded, approved and deployed in their environment," the advisory explains. 

The scramble to patch this vulnerability highlights the extreme sensitivity of flaws found within security products, say experts in the field. 

"The irony is that it is the product that is designed to protect these operating systems against malware which can now be targeted as a result of finding this issue," says Darron Gibbard, CTSO at Qualys. 

Steven Malone, director of security product management at email security company Mimecast agrees, explaining that the incident is also good lesson on why it's never good to depend on a single layer of security.

"Desktop security products often need high privileges in order to see everything and therefore any vulnerabilities can be particularly deadly," he says. "Incidents like this highlight that advanced security still requires a defense-in-depth strategy."

Related Content:

Ericka Chickowski specializes in coverage of information technology and business innovation. She has focused on information security for the better part of a decade and regularly writes about the security industry as a contributor to Dark Reading.  View Full Bio

Comment  | 
Print  | 
More Insights
Comments
Newest First  |  Oldest First  |  Threaded View
7 Ways VPNs Can Turn from Ally to Threat
Curtis Franklin Jr., Senior Editor at Dark Reading,  9/21/2019
Security Pros Value Disclosure ... Sometimes
Dark Reading Staff 9/19/2019
Register for Dark Reading Newsletters
White Papers
Video
Cartoon Contest
Write a Caption, Win a Starbucks Card! Click Here
Latest Comment: I wish they'd put a sock in it.
Current Issue
7 Threats & Disruptive Forces Changing the Face of Cybersecurity
This Dark Reading Tech Digest gives an in-depth look at the biggest emerging threats and disruptive forces that are changing the face of cybersecurity today.
Flash Poll
The State of IT Operations and Cybersecurity Operations
The State of IT Operations and Cybersecurity Operations
Your enterprise's cyber risk may depend upon the relationship between the IT team and the security team. Heres some insight on what's working and what isn't in the data center.
Twitter Feed
Dark Reading - Bug Report
Bug Report
Enterprise Vulnerabilities
From DHS/US-CERT's National Vulnerability Database
CVE-2019-10754
PUBLISHED: 2019-09-23
Multiple classes used within Apereo CAS before release 6.1.0-RC5 makes use of apache commons-lang3 RandomStringUtils for token and ID generation which makes them predictable due to RandomStringUtils PRNG's algorithm not being cryptographically strong.
CVE-2019-10755
PUBLISHED: 2019-09-23
The SAML identifier generated within SAML2Utils.java was found to make use of the apache commons-lang3 RandomStringUtils class which makes them predictable due to RandomStringUtils PRNG's algorithm not being cryptographically strong. This issue only affects the 3.X release of pac4j-saml.
CVE-2019-1255
PUBLISHED: 2019-09-23
A denial of service vulnerability exists when Microsoft Defender improperly handles files, aka 'Microsoft Defender Denial of Service Vulnerability'.
CVE-2019-1367
PUBLISHED: 2019-09-23
A remote code execution vulnerability exists in the way that the scripting engine handles objects in memory in Internet Explorer, aka 'Scripting Engine Memory Corruption Vulnerability'. This CVE ID is unique from CVE-2019-1221.
CVE-2019-11277
PUBLISHED: 2019-09-23
Cloud Foundry NFS Volume Service, 1.7.x versions prior to 1.7.11 and 2.x versions prior to 2.3.0, is vulnerable to LDAP injection. A remote authenticated malicious space developer can potentially inject LDAP filters via service instance creation, facilitating the malicious space developer to deny se...