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CVE-2022-42475: Fortinet FortiOS Heap-Based Buffer Overflow Vulnerability

CVE-2022-42475 is rated critical with a CVSS v3.1 base score of 9.8 and affects Fortinet FortiOS. Per its scoring, it can be exploited over the network, without authentication, without any user interaction. The scored impact on confidentiality, integrity and availability is the highest available. CISA added it to its Known Exploited Vulnerabilities catalog on 2022-12-13, which means exploitation in the wild has been observed.

Vulnerability description

A heap-based buffer overflow vulnerability [CWE-122] in FortiOS SSL-VPN 7.2.0 through 7.2.2, 7.0.0 through 7.0.8, 6.4.0 through 6.4.10, 6.2.0 through 6.2.11, 6.0.15 and earlier and FortiProxy SSL-VPN 7.2.0 through 7.2.1, 7.0.7 and earlier may allow a remote unauthenticated attacker to execute arbitrary code or commands via specifically crafted requests.

Severity breakdown

CVSS v3.1 9.8: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

  • Attack vector: Network. Exploitable remotely over the network, with no need for local or physical access.
  • Attack complexity: Low. No special conditions; the attack can be repeated reliably.
  • Privileges required: None. No account or prior access is needed.
  • User interaction: None. No action from any user is needed.
  • Scope: Unchanged. Impact stays within the vulnerable component.
  • Confidentiality impact: High. Total loss of confidentiality; sensitive data can be fully disclosed.
  • Integrity impact: High. Total loss of integrity; data or system state can be fully modified.
  • Availability impact: High. Total loss of availability; the component can be shut down.

Underlying weakness

CWE-197: Numeric Truncation Error

Truncation errors occur when a primitive is cast to a primitive of a smaller size and data is lost in the conversion.

CWE-787: Out-of-bounds Write

The product writes data past the end, or before the beginning, of the intended buffer.

Affected products

  • Fortinet Fortios: from 5.0.0 up to and including 5.0.14; from 5.2.0 up to and including 5.2.15; from 5.4.0 up to and including 5.4.13; from 5.6.0 up to and including 5.6.14; from 6.0.0 before 6.0.16; from 6.2.0 before 6.2.12; from 6.4.0 before 6.4.11; from 7.0.0 before 7.0.9; from 7.2.0 before 7.2.3; from 6.0.0 before 6.0.15; from 6.4.0 before 6.4.10; from 7.0.0 before 7.0.8
  • Fortinet Fortiproxy: from 1.0.0 up to and including 1.0.7; from 1.1.0 up to and including 1.1.6; from 1.2.0 up to and including 1.2.13; from 2.0.0 before 2.0.12; from 7.0.0 before 7.0.8; from 7.2.0 before 7.2.2

References