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.

Attacks/Breaches

4/4/2019
07:25 PM
Connect Directly
Twitter
LinkedIn
RSS
E-Mail
100%
0%

Threat Group Employs Amazon-Style Fulfillment Model to Distribute Malware

The operators of the Necurs botnet are using a collection of US-based servers to send out banking Trojans, ransomware, and other malware on behalf of other cybercriminals.

A threat group with possible connections to the operators of the notorious Necurs botnet has employed what security vendor Bromium this week described as an Amazon-style fulfillment model to host and distribute malware on behalf of other cybercriminals.

The group is using a collection of more than one dozen US-based servers to help attackers distribute a variety of ransomware, banking Trojans, and other malware to targets located mostly within the country.

The IP addresses of the hosting servers belong to a single autonomous system — or range of IP addresses — registered with a so-called "bulletproof" hosting company in the US. Eleven of the servers hosting malware are located in a single data center in Nevada belonging to the company.

Typically, malware hosting servers are located in jurisdictions known to be uncooperative with law enforcement. The fact that this particular group is operating from within the US using a highly consolidated set of servers is significant, says a malware researcher at Bromium, who did not wish to be identified.

"One benefit of the infrastructure being in the US is that the connections to download the malware are more likely to succeed inside organizations that block traffic to and from countries outside of their typical profile of network traffic."

Bromium has been tracking the group's operation for close to a year and says it has observed the US-based servers being used to host at least five families of banking Trojans, two ransomware families, and three information stealers. The malware includes the Dridex banking Trojan, GandCrab ransomware, and the Neutrino exploit kit.

Evidence suggests that a single group is hosting the malware and also distributing it via mass phishing campaigns on behalf of other threat actors. The use of the same servers to host multiple malware families, for instance, suggests that a single entity is behind the operation, Bromium said.

Similarly, all of the hosting servers have the same default Apache HTTP server and CentOS software builds, and the malicious files were also always hosted in the same root directory on each of the servers, the security vendor said. In each case, there is also no evidence that the servers were ever used for legitimate purposes, meaning they were provisioned purely to host and distribute malware.

The phishing emails that are being used to distribute the malware are also strikingly similar, indicating that the same threat group is sending them out. Many of the emails, for instance, have Microsoft Word documents with malicious VBA macros and contain links pointing back to the same set of servers. All of the macros also use a hard-coded IP address rather than a domain name for the server hosting the second-stage malware.

"Our research suggests that these campaigns are part of a highly organized 'Amazon-style' fulfilment operation," the Bromium researcher says. A distinct threat actor is responsible for email and hosting, while others are charge of operating the malware, he notes. "The entity that controls the hosting infrastructure represents a 'choke point' in the operations of the groups behind these malware families."

The separation of command and control from hosting and distribution suggests that any data stolen from victims is likely being stored elsewhere, the researcher says.

According to Bromium, the fact that Dridex was hosted on one of the web servers and similarities in the manner in which the malware is being distributed suggest the operators of the Necurs botnet are behind the latest operation as well.  

The operators of Dridex have been using Necurs to distribute the malware since 2016. So, it is possible that the collection of web servers being used to host and push out the 10 different malware families is part of the infrastructure used by the operators of Necurs, Bromium said.

Bromium has notified relevant authorities about the US-based company that is hosting the rogue servers. The company and its affiliates have legitimate customers, many of whom are likely attracted by the cheap web hosting rates offered. There are close to 53,000 IP addresses registered to the company, of which only a fraction were found to be hosting malicious content, the Bromium researcher says.

Related Content:

 

 

Join Dark Reading LIVE for two cybersecurity summits at Interop 2019. Learn from the industry's most knowledgeable IT security experts. Check out the Interop agenda here.

Jai Vijayan is a seasoned technology reporter with over 20 years of experience in IT trade journalism. He was most recently a Senior Editor at Computerworld, where he covered information security and data privacy issues for the publication. Over the course of his 20-year ... View Full Bio
 

Recommended Reading:

Comment  | 
Print  | 
More Insights
Comments
Oldest First  |  Newest First  |  Threaded View
News
FluBot Malware's Rapid Spread May Soon Hit US Phones
Kelly Sheridan, Staff Editor, Dark Reading,  4/28/2021
Slideshows
7 Modern-Day Cybersecurity Realities
Steve Zurier, Contributing Writer,  4/30/2021
Commentary
How to Secure Employees' Home Wi-Fi Networks
Bert Kashyap, CEO and Co-Founder at SecureW2,  4/28/2021
Register for Dark Reading Newsletters
White Papers
Video
Cartoon Contest
Current Issue
2021 Top Enterprise IT Trends
We've identified the key trends that are poised to impact the IT landscape in 2021. Find out why they're important and how they will affect you today!
Flash Poll
How Enterprises are Developing Secure Applications
How Enterprises are Developing Secure Applications
Recent breaches of third-party apps are driving many organizations to think harder about the security of their off-the-shelf software as they continue to move left in secure software development practices.
Twitter Feed
Dark Reading - Bug Report
Bug Report
Enterprise Vulnerabilities
From DHS/US-CERT's National Vulnerability Database
CVE-2021-31755
PUBLISHED: 2021-05-07
An issue was discovered on Tenda AC11 devices with firmware through 02.03.01.104_CN. A stack buffer overflow vulnerability in /goform/setmac allows attackers to execute arbitrary code on the system via a crafted post request.
CVE-2021-31756
PUBLISHED: 2021-05-07
An issue was discovered on Tenda AC11 devices with firmware through 02.03.01.104_CN. A stack buffer overflow vulnerability in /gofrom/setwanType allows attackers to execute arbitrary code on the system via a crafted post request. This occurs when input vector controlled by malicious attack get copie...
CVE-2021-31757
PUBLISHED: 2021-05-07
An issue was discovered on Tenda AC11 devices with firmware through 02.03.01.104_CN. A stack buffer overflow vulnerability in /goform/setVLAN allows attackers to execute arbitrary code on the system via a crafted post request.
CVE-2021-31758
PUBLISHED: 2021-05-07
An issue was discovered on Tenda AC11 devices with firmware through 02.03.01.104_CN. A stack buffer overflow vulnerability in /goform/setportList allows attackers to execute arbitrary code on the system via a crafted post request.
CVE-2021-31458
PUBLISHED: 2021-05-07
This vulnerability allows remote attackers to execute arbitrary code on affected installations of Foxit Reader 10.1.1.37576. User interaction is required to exploit this vulnerability in that the target must visit a malicious page or open a malicious file. The specific flaw exists within the handlin...