Threat Intelligence

3/26/2018
05:30 PM
50%
50%

New Ransomware Attacks Endpoint Defenses

AVCrypt tries to disable anti-malware software before it can be detected and removed.

A newly discovered ransomware variant attempts to remove any anti-malware protection in place on a victim's computer before it begins its nefarious work.

A group of researchers that includes Lawrence Abrams (of bleepingcomputer.com), MalwareHunterTeam, and Michael Gillespie discovered the malware and reported it in a post on BleepingComputer. The malware, which the group of analysts and researchers is calling AVCrypt, first tries to identify and remove a number of Windows services that are required for two specific anti-virus packages, Windows Defender and Malwarebytes, to operate successfully.

Abrams said in his post that AVCrypt seems at best incomplete because of major missing pieces. While it does contact a command and control server and encrypt files, it doesn't actually include any ransom instructions or provisions for decryption.

In a Twitter conversation about the ransomware, several participants point out that other types of malware have been able to disable particular antivirus packages, but that this is new behavior for ransomware. It's also noted that AVCrypt specifically targets Malwarebytes and Windows Defender. Defender is the default antivirus package from Microsoft that's typically activated if the user decides not to install other AV software.

MalwareHunterTeam also pointed out in the Twitter exchange that AVCrypt will abort a shutdown sequence command in an attempt to prevent the user from staying safe by "pulling the plug" on a machine. The combination of behaviors could make a number of the standard processes for an emergency recovery unworkable.

While the specific ransomware variant discussed in the article is new, there are significant similarities to other malware code seen previously. In a Twitter discussion with Michael Gillespie, Microsoft's Windows Defender Security Intelligence tweeted, "#WindowsDefenderAV blocked this #ransomware at the onset using proactive cloud-based protection. We're seeing very limited instances of this ransomware, it does look like it's in development. We detect this new threat as Ransom:Win32/Pactelung.A."

It seems that the curtain has been pulled back on a very new, very immature ransomware variant before it could be released into the wild in its finished form. The delivery mechanisms for AVCrypt appear to be the standard methods seen in other ransomware, including malicious spam, drive-by URLs, and pirated software. For now, it appears that stringent applications of existing protection should protect organizations against AVCrypt.

Related Content:

Interop ITX 2018

Join Dark Reading LIVE for two cybersecurity summits at Interop ITX. Learn from the industry’s most knowledgeable IT security experts. Check out the security track here. Register with Promo Code DR200 and save $200.

Curtis Franklin Jr. is Senior Editor at Dark Reading. In this role he focuses on product and technology coverage for the publication. In addition he works on audio and video programming for Dark Reading and contributes to activities at Interop ITX, Black Hat, INsecurity, and ... View Full Bio

Comment  | 
Print  | 
More Insights
Comments
Newest First  |  Oldest First  |  Threaded View
Microsoft President: Governments Must Cooperate on Cybersecurity
Kelly Sheridan, Staff Editor, Dark Reading,  11/8/2018
To Click or Not to Click: The Answer Is Easy
Kowsik Guruswamy, Chief Technology Officer at Menlo Security,  11/14/2018
Veterans Find New Roles in Enterprise Cybersecurity
Kelly Sheridan, Staff Editor, Dark Reading,  11/12/2018
Register for Dark Reading Newsletters
White Papers
Video
Cartoon
Current Issue
Flash Poll
Online Malware and Threats: A Profile of Today's Security Posture
Online Malware and Threats: A Profile of Today's Security Posture
This report offers insight on how security professionals plan to invest in cybersecurity, and how they are prioritizing their resources. Find out what your peers have planned today!
Twitter Feed
Dark Reading - Bug Report
Bug Report
Enterprise Vulnerabilities
From DHS/US-CERT's National Vulnerability Database
CVE-2018-19279
PUBLISHED: 2018-11-14
PRIMX ZoneCentral before 6.1.2236 on Windows sometimes leaks the plaintext of NTFS files. On non-SSD devices, this is limited to a 5-second window and file sizes less than 600 bytes. The effect on SSD devices may be greater.
CVE-2018-19280
PUBLISHED: 2018-11-14
Centreon 3.4.x has XSS via the resource name or macro expression of a poller macro.
CVE-2018-19281
PUBLISHED: 2018-11-14
Centreon 3.4.x allows SNMP trap SQL Injection.
CVE-2018-17960
PUBLISHED: 2018-11-14
CKEditor 4.x before 4.11.0 allows user-assisted XSS involving a source-mode paste.
CVE-2018-19278
PUBLISHED: 2018-11-14
Buffer overflow in DNS SRV and NAPTR lookups in Digium Asterisk 15.x before 15.6.2 and 16.x before 16.0.1 allows remote attackers to crash Asterisk via a specially crafted DNS SRV or NAPTR response, because a buffer size is supposed to match an expanded length but actually matches a compressed lengt...