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

Comment  | 
Print  | 
More Insights
Comments
Oldest First  |  Newest First  |  Threaded View
AI Is Everywhere, but Don't Ignore the Basics
Howie Xu, Vice President of AI and Machine Learning at Zscaler,  9/10/2019
Fed Kaspersky Ban Made Permanent by New Rules
Dark Reading Staff 9/11/2019
Register for Dark Reading Newsletters
White Papers
Video
Cartoon Contest
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-2019-4147
PUBLISHED: 2019-09-16
IBM Sterling File Gateway 2.2.0.0 through 6.0.1.0 is vulnerable to SQL injection. A remote attacker could send specially-crafted SQL statements, which could allow the attacker to view, add, modify or delete information in the back-end database. IBM X-Force ID: 158413.
CVE-2019-5481
PUBLISHED: 2019-09-16
Double-free vulnerability in the FTP-kerberos code in cURL 7.52.0 to 7.65.3.
CVE-2019-5482
PUBLISHED: 2019-09-16
Heap buffer overflow in the TFTP protocol handler in cURL 7.19.4 to 7.65.3.
CVE-2019-15741
PUBLISHED: 2019-09-16
An issue was discovered in GitLab Omnibus 7.4 through 12.2.1. An unsafe interaction with logrotate could result in a privilege escalation
CVE-2019-16370
PUBLISHED: 2019-09-16
The PGP signing plugin in Gradle before 6.0 relies on the SHA-1 algorithm, which might allow an attacker to replace an artifact with a different one that has the same SHA-1 message digest, a related issue to CVE-2005-4900.