The VPNFilter malware is a globally deployed threat infected thousands of network devices across the globe, it is a multi-stage, modular platform with versatile capabilities to support both intelligence-collection and destructive cyber attack operations.
It was uncovered by Talos researchers, the malware infects more than 500,000 in at least 54 countries and the targeted devices are Linksys, MikroTik, NETGEAR and TP-Link networking equipment in the organization and NAS devices.
Talos researchers observed the VPNFilter Malware adds additional third-stage modules to expand its ability to exploit endpoint systems and to encrypt malicious traffic.
VPNFilter malware adds these seven additional third-stage modules
htpx – It is a is a third-stage module responsible for setting rules on iptables and to redirect the network traffic and to inspect the contents of the HTTP traffic.
ndbr – The ndbr is a multi-functional SSH tool that has the ability to perform port-scan other IPs.
nm – It is a network module that scans and map the local subnet from the compromised devices. It goes through all interfaces and starts by ARP scanning, if it gets ARP reply then send ICMP packets to discover the host.
netfilter – Module used to deny access to certain encrypted applications for victims that threat actors preferred to use.
portforwarding – The module is designed to forward the network traffic to the infrastructure specified by the attacker.
socks5proxy – To establish a SOCKS5 proxy on the compromised devices to communicate with the C2 server.
tcpvpn – Module allows to establish a Reverse-TCP VPN connection on the compromised devices. It allows a remote to access internal networks behind infected devices.
Stages of VPNFilter Malware Operation
Stage 1 – The malware ensures persistence, it can survive after a reboot, where most of the malware that targets internet-of-things devices does not survive after reboot.
Stage 2 – The malware with multiple capabilities such as file collection, command execution, data exfiltration, and device management.
Stage 3 – It acts as a plugin for Stage 2, it contains the sniffer module for collecting traffic data and communication module that allows Stage 2 malware to connect to C2 server through Tor Service.
“VPNFilter coupled with our new findings, we now confirm that VPNFilter provides attackers all of the functionality required to leverage compromised network and storage devices to further pivot into and attack systems within the network environments that are being targeted.” researchers said.