FBI, CISA Warn Of Threat Actors Targeting Old Fortinet FortiOS Vulns

The FBI and Cybersecurity and Infrastructure Agency are warning of sophisticated malicious actors exploiting multiple older vulnerabilities in Fortinet FortiOS to gain access to customer networks.

The advisory, issued last week, warns that advanced persistent threat (APT) actors are scanning devices for three different vulnerabilities to infiltrate the networks of government, commercial and technology service networks.

The agencies say the vulnerabilities in Fortinet FortiOS are CVE 2018-13379, CVE-2020-12812, and CVE-2019-5591, and the actors may be using any or all of the vulnerabilities to gain access to networks “across multiple critical infrastructure sectors” and establish a persistent presence for follow-on data exfiltration or ransomware attacks.

Fortinet FortiOS is the operating system on which the company’s Fortinet Security Fabric solution runs. It is designed to secure “the entire digital attack surface” of its enterprise customers, according to the company.

“APT actors may use other CVEs or common exploitation techniques—such as spearphishing—to gain access to critical infrastructure networks to pre-position for follow-on attacks,” the advisory said.

All three vulnerabilities have patches available, but threat actors are scanning for unpatched versions of the product, the alert says.

In a statement to Channel Futures, Fortinet said the vulnerabilities were resolved in 2019 and 2020.

To mitigate, IT administrators should first update and apply the patches if they didn’t already.

Other mitigation steps, per CISA and the FBI, include:

• If FortiOS is not used by your organization, add key artifact files used by FortiOS to your organization’s execution deny list. Any attempts to install or run this program and its associated files should be prevented.
• Regularly back up data, air gap, and password protect backup copies offline. Ensure copies of critical data are not accessible for modification or deletion from the primary system where the data resides.
• Implement network segmentation.
• Require administrator credentials to install software.
• Implement a recovery plan to restore sensitive or proprietary data from a physically separate, segmented, secure location (e.g., hard drive, storage device, the cloud).
• Install updates/patch operating systems, software, and firmware as soon as updates/patches are released.
• Use multifactor authentication where possible.
• Regularly change passwords to network systems and accounts, and avoid reusing passwords for different accounts. Implement the shortest acceptable timeframe for password changes.
• Disable unused remote access/Remote Desktop Protocol (RDP) ports and monitor remote access/RDP logs.
• Audit user accounts with administrative privileges and configure access controls with least privilege in mind.
• Install and regularly update antivirus and anti-malware software on all hosts.
• Consider adding an email banner to emails received from outside your organization.
• Disable hyperlinks in received emails.
• Focus on awareness and training. Provide users with training on information security principles and techniques, particularly on recognizing and avoiding phishing emails.