FBI issued a flash alert about Netwalker ransomware attacks

The FBI has issued a security alert about Netwalker ransomware attacks targeting U.S. and foreign government organizations.

The FBI has issued a new security flash alert to warn of Netwalker ransomware attacks targeting U.S. and foreign government organizations. The feds are recommending victims, not to pay the ransom and reporting incidents to their local FBI field offices.

The flash alert also includes indicators of compromise for the Netwalker ransomware along with mitigations.

The FBI warns of a new wave of Netwalker ransomware attacks that began in June, the list of victims includes the UCSF School of Medicine and the Australian logistics giant Toll Group.

“As of June 2020, the FBI has received notifications of Netwalker ransomware attacks on U.S. and foreign government organizations, education entities, private companies, and health agencies by unidentified cyber actors.” reads the alert. “Netwalker became widely recognized in March 2020, after intrusions on an Australian transportation and logistics company and a U.S. public health organization. Cyber actors using Netwalker have since taken advantage of the COVID-19 pandemic to compromise an increasing number of unsuspecting victims.”

The Netwalker ransomware operators have been very active since March and also took advantage of the ongoing COVID-19 outbreak to target organizations.

The threat actors initially leveraged phishing emails delivering a Visual Basic Scripting (VBS) loader, but since April 2020, Netwalker ransomware operators began exploiting vulnerable Virtual Private Network (VPN) appliances, user interface components in web apps, or weak passwords of Remote Desktop Protocol connections to gain access to their victims’ networks.

Recently the Netwalker ransomware operators were looking for new collaborators that can provide them with access to large enterprise networks. 

“Two of the most common vulnerabilities exploited by actors using Netwalker are Pulse Secure VPN (CVE-2019-11510) and Telerik UI (CVE-2019-18935).” continues the alert. “Once an actor has infiltrated a network with Netwalker, a combination of malicious programs may be executed to harvest administrator credentials, steal valuable data, and encrypt user files. In order to encrypt the user files on a victim network, the actors typically launch a malicious PowerShell script embedded with the Netwalker ransomware executable.”

Below the recommended mitigations provided by the FBI:

Back-up critical data offline. Ensure copies of critical data are in the cloud or on an external hard drive or storage device. Secure your back-ups and ensure data is not accessible for modification or deletion from the system where the data resides. Install and regularly update anti-virus or anti-malware software on all hosts. Only use secure networks and avoid using public Wi-Fi networks.Consider installing and using a VPN. Use two-factor authentication with strong passwords. Keep computers, devices, and applications patched and up-to-date.

The FBI advises victims not to pay the ransom.

Pierluigi Paganini

(SecurityAffairs – hacking, D-Link)