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87,000+ Fortinet devices still open to attack, are yours among them? (CVE-2024-23113)

criticalVulnerability exploited in the wildimportance 60CVE-2024-23113

Vulnerabilities mentionedAll →

CVEVulnerabilityCVSSEPSSFlagsAffectedExposurePublished
CVE-2024-23113
Format String Vulnerability Enables Unauthenticated RCE in Fortinet FortiOS and FortiProxy

CVE-2024-23113 is a use of externally-controlled format string (CWE-134) in multiple Fortinet products, allowing an unauthenticated remote attacker to execute unauthorized code or commands by sending specially crafted packets to an affected device. The flaw carries a critical CVSS 3.1 score of 9.8 (network vector, no privileges or user interaction required, high impact on confidentiality, integrity, and availability). It affects FortiOS 7.0.0 through 7.0.13, 7.2.0 through 7.2.6, and 7.4.0 through 7.4.2; FortiProxy 7.0.0 through 7.0.14, 7.2.0 through 7.2.8, and 7.4.0 through 7.4.2; FortiPAM 1.0.0 through 1.0.3, 1.1.0 through 1.1.2, and 1.2.0; and FortiSwitchManager 7.0.0 through 7.0.3 and 7.2.0 through 7.2.3. CISA added the vulnerability to the Known Exploited Vulnerabilities catalog on 2024-10-09 and warns it is likely being exploited in the wild, though no public proof-of-concept is known. Scanning coverage reported in the trade press indicates roughly 87,000 or more internet-exposed Fortinet devices remained vulnerable and open to attack after disclosure.

Do: Upgrade affected FortiOS, FortiProxy, FortiPAM, and FortiSwitchManager deployments to a patched release per Fortinet's advisory, since the data does not specify fixed build numbers. Until patching is complete, restrict management interface access to trusted sources, minimize internet exposure of affected devices, and verify your version falls within the affected ranges above. Treat this as an actively exploited vulnerability per CISA's KEV listing (added 2024-10-09) and prioritize it accordingly.

9.862% KEV
  • Fortinet FortiOS 7.4.0 through 7.4.2, 7.2.0 through 7.2.6, 7.0.0 through 7.0.13
  • Fortinet FortiProxy 7.4.0 through 7.4.2, 7.2.0 through 7.2.8, 7.0.0 through 7.0.14
  • Fortinet FortiPAM 1.2.0, 1.1.0 through 1.1.2, 1.0.0 through 1.0.3
  • +1 more
large≈87,000+ internet-exposed Fortinet devices per public scans (FortiOS/FortiProxy deployments; total installed base larger, affected-version share unknown)
Full article481 words · extracted from helpnetsecurity.com · click to collapse

Last week, CISA added CVE-2024-23113 – a critical vulnerability that allows unauthenticated remote code/command execution on unpatched Fortinet FortiGate firewalls – to its Known Exploited Vulnerabilities catalog, thus confirming that it’s being leveraged by attackers in the wild.

CVE-2024-23113

The Shadowserver Foundation shared on Sunday that there are still 87,000+ internet-facing Fortinet devices likely vulnerable to the flaw.

About CVE-2024-23113

CVE-2024-23113, a format string vulnerability that affects the FortiOS FGFM (FortiGate to FortiManager) daemon and can be triggered via specially crafted requests, was discovered and reported by Gwendal Guégniaud of Fortinet Product Security team and patched in early February 2024 in FortiOS versions 7.4.3, 7.2.7 and 7.0.14.

Since then, Fortinet’s advisory has been modified to confirm additional affected products and to share a mitigation measure that includes removing FGFM access.

“Note that this will prevent FortiGate discovery from FortiManager [a solution for managing Fortinet products]. Connection will still be possible from FortiGate,” the company warned.

“Please also note that a local-in policy that only allows FGFM connections from a specific IP will reduce the attack surface but it won’t prevent the vulnerability from being exploited from this IP. As a consequence, this should be used as a mitigation and not as a complete workaround.”

At the time, the vulnerability did not attract much attention from the cybersecurity community, but it’s now obvious that it didn’t pass unnoticed by threat actors.

Unfortunately, details about the attacks are still under wraps, and we don’t know whether the bug is being exploited for cyber espionage or ransomware delivery.

On Monday, watchTowr Labs released their analysis of the vulnerability and shared the difficulties they encountered when leveraging a tool they created for testing for its presence, due to the various firmware versions reacting differently to probing attempts.

“It looks like Fortinet added some kind of certificate validation logic in the 7.4 series, meaning that we can’t even connect to it (let alone send our payload) without being explicitly permitted by a device administrator. We also checked the 7.0 branch, and here we found things even more interesting, as an unpatched instance would allow us to connect with a self-signed certificate, while a patched machine requires a certificate signed by a configured CA,” watchTowr Labs researcher Aliz Hammond explained.

“We did some reversing and determined that the certificate must be explicitly configured by the administrator of the device, which limits exploitation of these machines to the managing FortiManager instance (which already has superuser permissions on the device) or the other component of a high-availability pair.”

Enterprise admins are advised to upgrade affected devices to a version containing the fix and, according to security researcher Kevin Beaumont, to be on the lookout for FortiManager patches fixing an undisclosed flaw affecting the same component (i.e., FGFM).

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Text extracted automatically; images, tables and formatting may be missing. Original: https://www.helpnetsecurity.com/2024/10/15/cve-2024-23113/