CVE-2023-22639 in FortiOS
Summary
by MITRE • 06/13/2023
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 6.4.12, FortiOS all versions 6.2, FortiOS all versions 6.0, FortiProxy version 7.2.0 through 7.2.2, FortiProxy version 7.0.0 through 7.0.8, FortiProxy all versions 2.0, FortiProxy all versions 1.2, FortiProxy all versions 1.1, FortiProxy all versions 1.0 allows attacker to escalation of privilege via specifically crafted commands.
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Analysis
by VulDB Data Team • 07/08/2023
This vulnerability represents a critical out-of-bounds write flaw affecting multiple Fortinet FortiOS and FortiProxy versions, classified under CWE-787 as an out-of-bounds write condition. The flaw exists in the authentication and privilege escalation handling mechanisms within the affected software versions, specifically when processing specially crafted commands that bypass normal input validation procedures. Attackers can exploit this vulnerability to execute arbitrary code with elevated privileges, potentially leading to complete system compromise and unauthorized access to sensitive network infrastructure. The vulnerability affects a broad range of Fortinet products including FortiOS versions 6.0.x through 7.2.x and FortiProxy versions 1.0 through 2.0, making it particularly concerning for enterprise networks relying on these security appliances.
The technical implementation of this vulnerability stems from inadequate bounds checking in memory allocation routines when processing user-supplied input through command interfaces. When legitimate administrative commands are crafted with malicious payload structures, the system fails to properly validate input boundaries before writing data to memory locations, resulting in overwriting adjacent memory regions. This memory corruption can be leveraged to overwrite critical system variables, function pointers, or control flow information within the Fortinet appliances. The vulnerability's exploitation pathway aligns with ATT&CK technique T1068 which covers 'Exploitation for Privilege Escalation' and T1548.001 which addresses 'Abuse Elevation Control Mechanism'. The flaw essentially allows attackers to bypass authentication mechanisms and escalate their privileges from standard user levels to administrative access.
The operational impact of this vulnerability extends beyond simple privilege escalation, as it provides attackers with persistent access to network infrastructure that typically serves as a critical security control point. Compromised Fortinet appliances can be used to monitor network traffic, modify firewall rules, disable security controls, or serve as launch points for further attacks within the network perimeter. Organizations using affected Fortinet products face significant risk of data breaches, network infiltration, and disruption of security operations. The vulnerability's presence across multiple major FortiOS releases and FortiProxy versions means that many enterprises may be affected without realizing it, as these appliances are commonly deployed in critical network security roles. Security teams must immediately assess their network infrastructure for affected devices and implement appropriate mitigations to prevent exploitation.
Mitigation strategies should include immediate patching of all affected Fortinet appliances to the latest available versions, which contain memory boundary checks and input validation fixes. Network segmentation and access controls should be strengthened to limit exposure of these appliances to untrusted networks. Implementing intrusion detection systems with signatures for known exploitation patterns can help detect attempts to exploit this vulnerability. Additionally, organizations should conduct comprehensive vulnerability assessments to identify all instances of affected software across their network infrastructure. Regular monitoring of Fortinet security bulletins and implementing automated patch management processes will help prevent similar vulnerabilities from being exploited in the future. The vulnerability demonstrates the critical importance of maintaining up-to-date security software and proper input validation practices in enterprise security infrastructure.