Pierluigi Paganini February 10, 2024

U.S. Cybersecurity and Infrastructure Security Agency (CISA) adds Fortinet FortiOS bug to its Known Exploited Vulnerabilities catalog.

The U.S. Cybersecurity and Infrastructure Security Agency (CISA) added a Fortinet FortiOS Out-of-Bound write vulnerability, tracked as CVE-2024-21762, to its Known Exploited Vulnerabilities (KEV) catalog.

This week Fortinet warned that the recently discovered critical remote code execution vulnerability in FortiOS SSL VPN, tracked as CVE-2024-21762 (CVSS score 9.6), is actively exploited in attacks in the wild.

The security firm did not provide details about the attacks exploiting this vulnerability.

The issue is an out-of-bounds write vulnerability that can be exploited by sending specially crafted HTTP requests to vulnerable instances. The vendor recommends to disable SSL VPN as a workaround.

“A out-of-bounds write vulnerability [CWE-787] in FortiOS may allow a remote unauthenticated attacker to execute arbitrary code or command via specially crafted HTTP requests.” reads the advisory.

“Workaround : disable SSL VPN (disable webmode is NOT a valid workaround). Note: This is potentially being exploited in the wild.”

The following table includes the list of the impacted versions and the available versions that solve the issue.

According to Binding Operational Directive (BOD) 22-01: Reducing the Significant Risk of Known Exploited Vulnerabilities, FCEB agencies have to address the identified vulnerabilities by the due date to protect their networks against attacks exploiting the flaws in the catalog.

Experts recommend also private organizations review the Catalog and address the vulnerabilities in their infrastructure.

CISA orders federal agencies to fix this vulnerability by February 16, 2024.

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Pierluigi Paganini

(SecurityAffairs – Hacking, Fortinet)