Fortinet has privately informed some customers about a critical and remotely exploitable vulnerability that poses a significant risk.
The cybersecurity firm does not appear to have released a public advisory, but in emails sent to customers the company revealed that its FortiOS and FortiProxy products are affected by a critical authentication bypass vulnerability on the admin interface. The issue is tracked as CVE-2022-40684.
The email has only been distributed to ‘select customers’ and it’s marked as ‘strictly confidential’, with recipients instructed not to share it outside their organization. However, copies of the email have been shared on social media and even on Fortinet forums by customers.
“Fortinet is providing an advanced notification of a critical severity authentication bypass using an alternate path or channel [CWE-88] in specific versions of FortiOS and FortiProxy that may allow an unauthenticated attacker to perform operations on the administrative interface via specially crafted HTTP or HTTPS requests,” Fortinet said.
The company has instructed customers to immediately update their products due to attackers being able to remotely exploit the vulnerability.
FortiOS versions between 7.0.0 and 7.0.6, and between 7.2.0 and 7.2.1 are affected, as well as FortiProxy 7.0.0 through 7.0.6 and 7.2.0. FortiOS patches are included in versions 7.0.7 and 7.2.2, and fixes for FortiProxy are included in 7.0.7 and 7.2.1. There have also been some unconfirmed reports that versions 6.x.x could also be impacted.
Users can also prevent attacks by ensuring that only trusted IP addresses can reach the affected products’ administrative interface.
Threat intelligence company GreyNoise says it will be keeping an eye out for exploitation attempts, but for the time being there is not enough information for them to be able to identify attacks.
Threat intelligence firm Cyberthint reported seeing more than 150,000 potentially vulnerable Fortinet product instances that are exposed to the internet.
While it’s unclear if attacks exploiting CVE-2022-40684 have already begun, it’s not uncommon for threat actors to target vulnerabilities in Fortinet products.
UPDATE: Fortinet has made its advisory public. The company has also informed customers about CVE-2022-33873, which allows an unauthenticated remote attacker to execute arbitrary commands in the underlying shell.