Roughly one month ago, Fortinet patched a critical FortiOS vulnerability and warned customers about potential exploitation. Many systems are impacted, but there still do not appear to be any signs of large-scale attacks.
The vulnerability, tracked as CVE-2024-21762, has been described as an out-of-bounds write issue in FortiOS and FortiProxy that can allow a remote, unauthenticated attacker to execute arbitrary code or commands through specially crafted HTTP requests.
When it disclosed the zero-day flaw on February 9, Fortinet said it was ‘potentially being exploited in the wild’. CISA added CVE-2024-21762 to its Known Exploited Vulnerabilities Catalog a few days later.
No details seem to be available on attacks exploiting CVE-2024-21762 and there is currently no evidence of widespread attacks.
Fortinet vulnerabilities are often initially exploited in highly targeted attacks by sophisticated threat actors, but mass exploitation is not uncommon, particularly after a patch is released and information becomes public.
In this case, more than a month has passed since the initial disclosure and there are still no reports of mass attacks. Threat intelligence company GreyNoise, which conducted a technical analysis of the security hole, has been tracking CVE-2024-21762 exploitation attempts, but its honeypots have yet to see any attacks.
Fortinet also does not seem to have confirmed exploitation — its advisory still says ‘potentially being exploited’.
The non-profit cybersecurity organization Shadowserver is seeing nearly 150,000 Fortinet product instances that may be impacted by CVE-2024-21762, but it has not mentioned anything about seeing actual attack attempts.
The highest percentage of potentially vulnerable systems seen by Shadowserver is in the United States, followed by India. Thousands of instances have been seen in Europe, China, Canada, Mexico and Brazil.
Bishop Fox provides an open source tool that organizations can use to determine whether an appliance is impacted by the vulnerability.
Related: Fortinet Warns Customers of Possible Zero-Day Exploited in Limited Attacks
Related: Fortinet Patches Critical Vulnerabilities in FortiSIEM
Related: Fortinet Patches High-Severity Vulnerabilities in FortiOS, FortiProxy, FortiWeb Products
