CVE-2023-41675 in FortiOS
Summary
by MITRE • 10/25/2023
A use after free vulnerability [CWE-416] in FortiOS version 7.2.0 through 7.2.4 and version 7.0.0 through 7.0.10 and FortiProxy version 7.2.0 through 7.2.2 and version 7.0.0 through 7.0.8 may allow an unauthenticated remote attacker to crash the WAD process via multiple crafted packets reaching proxy policies or firewall policies with proxy mode alongside SSL deep packet inspection.
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Analysis
by VulDB Data Team • 10/25/2023
This vulnerability represents a critical use after free condition that affects Fortinet's FortiOS and FortiProxy products, specifically targeting versions within the 7.0 and 7.2 release lines. The flaw manifests as a CWE-416 classification, where memory that has been freed is subsequently accessed by the application, creating potential for arbitrary code execution or system instability. The vulnerability occurs within the WAD (Web Application Defense) process, which is responsible for handling proxy policies and firewall policies with SSL deep packet inspection capabilities. Attackers can exploit this weakness by sending multiple crafted packets that trigger the vulnerable code path, leading to a controlled crash of the WAD process.
The technical exploitation of this vulnerability requires an unauthenticated remote attacker to craft specific packets that can trigger the memory management error within the SSL deep packet inspection module. When the system processes these malicious packets through proxy policies, the memory allocation and deallocation sequence becomes corrupted, allowing the attacker to either cause a denial of service through process termination or potentially execute arbitrary code if the memory corruption can be leveraged effectively. The attack vector specifically targets the interaction between proxy policies and SSL deep packet inspection, which are common components in enterprise security appliances that handle encrypted traffic inspection.
The operational impact of this vulnerability extends beyond simple denial of service, as it represents a potential pathway for more sophisticated attacks that could compromise the overall security posture of affected networks. Organizations running vulnerable Fortinet appliances may experience service disruptions when the WAD process crashes, potentially affecting web application security, SSL inspection capabilities, and overall network traffic processing. The vulnerability affects both FortiOS and FortiProxy products, indicating a widespread impact across Fortinet's security portfolio. Security teams must consider that this flaw could be leveraged by attackers to gain persistent access to network infrastructure, particularly in environments where these appliances serve as critical security controls.
Mitigation strategies should focus on immediate patching of affected systems, with Fortinet releasing updates that address the memory management issues in the WAD process. Network administrators should implement temporary network segmentation to limit exposure while patches are deployed, and monitor for any signs of exploitation attempts. The vulnerability aligns with ATT&CK techniques related to service stoppage and denial of service attacks, making it particularly concerning for organizations that rely heavily on SSL inspection capabilities. Organizations should also consider implementing additional monitoring for unusual WAD process behavior and packet patterns that could indicate exploitation attempts, as the use after free condition may leave traces that can be detected through proper log analysis and security monitoring systems.