CVE-2023-22640 in FortiOS
Summary
by MITRE • 05/04/2023
A out-of-bounds write in Fortinet FortiOS version 7.2.0 through 7.2.3, FortiOS version 7.0.0 through 7.0.10, FortiOS version 6.4.0 through 6.4.11, FortiOS version 6.2.0 through 6.2.13, FortiOS all versions 6.0, FortiProxy version 7.2.0 through 7.2.1, FortiProxy version 7.0.0 through 7.0.7, FortiProxy all versions 2.0, FortiProxy all versions 1.2, FortiProxy all versions 1.1, FortiProxy all versions 1.0 allows an authenticated attacker to execute unauthorized code or commands via specifically crafted requests.
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Analysis
by VulDB Data Team • 05/27/2023
This vulnerability represents a critical out-of-bounds write flaw that affects multiple versions of Fortinet's FortiOS and FortiProxy products, creating a significant attack surface for authenticated threat actors. The vulnerability stems from improper input validation within the network security appliance software, specifically when processing specially crafted requests that exceed allocated memory boundaries. This flaw exists across several major version lines including FortiOS 6.0, 6.2, 6.4, 7.0, and 7.2 releases, as well as various FortiProxy versions, indicating a widespread issue that has persisted across multiple software generations. The out-of-bounds write condition occurs when the system fails to properly validate the size or content of incoming requests, allowing an attacker with valid credentials to manipulate memory allocation and potentially overwrite adjacent memory locations.
The technical implementation of this vulnerability involves an authenticated attacker exploiting a memory management flaw that can be triggered through crafted HTTP or network protocol requests. When the vulnerable system processes these malicious inputs, it writes data beyond the boundaries of allocated memory buffers, potentially corrupting adjacent memory regions that contain critical system data, function pointers, or control structures. This type of vulnerability falls under CWE-787 Out-of-bounds Write, which is classified as a high-severity issue in the Common Weakness Enumeration catalog. The flaw enables privilege escalation and arbitrary code execution capabilities, as the attacker can manipulate the program flow by overwriting critical memory locations with malicious payloads.
The operational impact of CVE-2023-22640 extends beyond simple denial of service scenarios, as it provides attackers with the capability to execute unauthorized commands on affected systems. This vulnerability can be leveraged to gain persistent access to network infrastructure, potentially allowing threat actors to establish backdoors, exfiltrate sensitive data, or disrupt critical network operations. The authenticated nature of the attack means that an attacker must first obtain valid credentials, but this requirement does not significantly limit the exploitability given that many organizations maintain extensive user bases for administrative access. The vulnerability affects network security appliances that serve as critical infrastructure components, making successful exploitation particularly dangerous for enterprise environments that rely on Fortinet products for network protection.
Organizations should implement immediate mitigations including applying the latest security patches released by Fortinet, which address the memory validation issues in the affected software versions. Network segmentation and access control measures should be enhanced to limit the blast radius of potential exploitation, while monitoring systems should be configured to detect anomalous authentication patterns or unusual request traffic that might indicate exploitation attempts. The ATT&CK framework categorizes this vulnerability under T1059 Command and Scripting Interpreter and T1068 Exploitation for Privilege Escalation, indicating that successful exploitation would likely involve command execution and privilege elevation techniques. Additionally, organizations should conduct thorough vulnerability assessments of their Fortinet deployments to identify all affected systems and ensure complete remediation across their network infrastructure.