Fortinet Warns of Active Exploitation of Newly Discovered Critical Auth Bypass Bug

Fortinet on Monday revealed that the newly patched critical security vulnerability impacting its firewall and proxy products is being actively exploited in the wild.

Tracked as CVE-2022-40684 (CVSS score: 9.6), the flaw relates to an authentication bypass in FortiOS, FortiProxy, and FortiSwitchManager that could allow a remote attacker to perform unauthorized operations on the administrative interface via specially crafted HTTP(S) requests.

“Fortinet is aware of an instance where this vulnerability was exploited, and recommends immediately validating your systems against the following indicator of compromise in the device’s logs: user=‘Local_Process_Access,’” the company noted in an advisory.

The list of impacted devices is below -

• FortiOS version 7.2.0 through 7.2.1
• FortiOS version 7.0.0 through 7.0.6
• FortiProxy version 7.2.0
• FortiProxy version 7.0.0 through 7.0.6
• FortiSwitchManager version 7.2.0, and
• FortiSwitchManager version 7.0.0

Updates have been released by the security company in FortiOS versions 7.0.7 and 7.2.2, FortiProxy versions 7.0.7 and 7.2.1, and FortiSwitchManager version 7.2.1.

The disclosure comes days after Fortinet sent “confidential advance customer communications” to its customers, urging them to apply patches to mitigate potential attacks exploiting the flaw.

If updating to the latest version isn’t an option, it’s recommended that users disable the HTTP/HTTPS administrative interface, or alternatively limit IP addresses that can access the administrative interface.

Update: The U.S. Cybersecurity and Infrastructure Security Agency (CISA) on Tuesday added the Fortinet flaw to its Known Exploited Vulnerabilities (KEV) catalog, requiring federal agencies to apply patches by November 1, 2022.

Details and proof-of-concept (PoC) code for the vulnerability are expected to become publicly available in the coming days, in a move that could enable other threat actors to adopt the exploit to their toolset and mount their own attacks.

“Vulnerabilities affecting devices on the edge of corporate networks are among the most sought after by threat actors because it leads to breaching the perimeter, and CVE-2022-40684 allows exactly this,” Zach Hanley, chief attack engineer at Horizon3.ai, said.

“Past Fortinet vulnerabilities, like CVE-2018-13379, have remained some of the top exploited vulnerabilities over the years and this one will likely be no different.”

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