SonicWall Breached Via Zero-Day Flaw In Remote Access Tools

Sophisticated hackers compromised SonicWall’s NetExtender VPN client and SMB-oriented Secure Mobile Access 100 series product, which are used to provide employees and users with remote access to internal resources.

SonicWall disclosed Friday night that highly sophisticated threat actors attacked its internal systems by exploiting a probable zero-day flaw on the company’s secure remote access products.

The Milpitas, Calif.-based platform security vendor said the compromised NetExtender VPN client and SMB-oriented Secure Mobile Access (SMA) 100 series products are used to provide employees and users with remote access to internal resources. The SMA 1000 series is not susceptible to this attack and utilizes clients different from NetExtender, according to SonicWall.

“We believe it is extremely important to be transparent with our customers, our partners and the broader cybersecurity community about the ongoing attacks on global business and government,” SonicWall wrote in an “Urgent Security Notice” posted to its product notifications webpage at 11:15 p.m. ET Friday. The company said the coordinated attack on its systems was identified “recently.”

[Related: SolarWinds Hackers Access Malwarebytes’ Office 365 Emails]

SonicWall declined to answer questions about whether the attack on its internal systems was carried out by the same threat actor who for months injected malicious code into the SolarWinds Orion network monitoring tool. The company, however, noted that it’s seen a “dramatic surge” in cyberattacks against firms that provide critical infrastructure and security controls to governments and businesses.

The company said it is providing mitigation recommendations to its channel partners and customers. Multi-factor authentication must be enabled on all SonicWall SMA, firewall and MySonicWall accounts, according to SonicWall.

Products compromised in the the SonicWall breach include: the NetExtender VPN client version 10.x (released in 2020) used to connect to SMA 100 series appliances and SonicWall firewalls; as well as SonicWall’s SMA version 10.x running on SMA 200, SMA 210, SMA 400, SMA 410 physical appliances and the SMA 500v virtual appliance.

SonicWall partners and customers using the SMA 100 series should either use a firewall to only allow SSL-VPN connections to the SMA appliance from known/whitelisted IPs or configure whitelist access on the SMA directly itself, according to the company.

For firewalls with SSN-VPN access using the compromised version of the NetExtender VPN client, partners and customers should either disable NetExtender access to the firewall(s) or restrict access to users and admins via an allow-list/whitelist for their public IPs, according to SonicWall.

SonicWall is the fifth pure-play cybersecurity vendor to publicly disclose an attack over the past seven weeks. FireEye blew the lid off what would become the SolarWinds hacking campaign Dec. 8 when company said that it was breached in an attack designed to gain information on some of its government customers. The attacker was able to access some of FireEye’s internal systems, the company said.

Then CrowdStrike disclosed Dec. 23 that it had been contacted eight days earlier by Microsoft’s Threat Intelligence Center, which had identified a reseller’s Microsoft Azure account making abnormal calls to Microsoft cloud APIs during a 17-hour period several months ago, according to CTO Michael Sentonas.

The reseller’s Azure account was used for managing CrowdStrike’s Microsoft Office licenses, and the hackers failed in their attempt to read the company’s email since CrowdStrike doesn’t use Office 365 email, according to Sentonas.

Then Mimecast announced Jan. 12 that a sophisticated threat actor had compromised a Mimecast-issued certificate used to authenticate several of the company’s products to Microsoft 365 Exchange Web Services. The compromised certificate was used to authenticate Mimecast’s Sync and Recover, Continuity Monitor and Internal Email Protect (IEP) products to Microsoft 365, the company disclosed.

Mimecast declined to answer CRN questions about whether its breach was carried out by the same group who attacked SolarWinds. But three cybersecurity officials told Reuters Jan. 12 they suspected the hackers who compromised Mimecast were the same group that broke into SolarWinds. The Washington Post reported that the SolarWinds attack was carried out by the Russian foreign intelligence service.

Most recently, Malwarebytes disclosed Tuesday that the SolarWinds hackers leveraged a dormant email production product within its Office 365 tenant that allowed access to a limited subset of internal company emails. Malwarebytes doesn’t itself use SolarWinds Orion, and learned about the attack from Microsoft following suspicious activity from a third-party application in the company’s Office 365 tenant.