CVE-2015-2281 in Single Sign On
Summary
by MITRE
Stack-based buffer overflow in collectoragent.exe in Fortinet Single Sign On (FSSO) before build 164 allows remote attackers to execute arbitrary code via a large PROCESS_HELLO message to the Message Dispatcher on TCP port 8000.
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Analysis
by VulDB Data Team • 05/04/2025
The vulnerability identified as CVE-2015-2281 represents a critical stack-based buffer overflow flaw within the Fortinet Single Sign On FSSO component, specifically affecting collectoragent.exe executable. This security weakness exists in Fortinet FSSO implementations prior to build 164 and constitutes a significant threat to network infrastructure security. The vulnerability stems from inadequate input validation mechanisms within the Message Dispatcher service that operates on TCP port 8000, creating an exploitable condition that remote attackers can leverage for malicious purposes. The flaw manifests when the system receives a specially crafted PROCESS_HELLO message that exceeds the allocated stack buffer size, leading to memory corruption and potential code execution.
The technical implementation of this vulnerability aligns with CWE-121, which describes stack-based buffer overflow conditions where insufficient bounds checking allows attackers to overwrite adjacent memory locations. The attack vector specifically targets the TCP port 8000 listener within the FSSO service architecture, where the collectoragent.exe process handles incoming communication from Fortinet authentication agents. When a maliciously formatted PROCESS_HELLO message is transmitted, the system's failure to properly validate the message length causes the stack buffer to overflow, potentially allowing an attacker to overwrite return addresses and function pointers within the call stack. This memory corruption enables remote code execution with the privileges of the affected service, typically running with elevated system permissions.
The operational impact of CVE-2015-2281 extends beyond simple code execution to encompass complete system compromise and potential lateral movement within network environments. Organizations utilizing Fortinet FSSO solutions prior to build 164 face substantial risk of unauthorized access to authentication infrastructure, which could lead to credential theft, unauthorized network access, and complete system takeover. The vulnerability's remote exploitability eliminates the need for physical access or local network presence, making it particularly dangerous for enterprise environments where FSSO services may be exposed to untrusted networks. Attackers can leverage this flaw to establish persistent backdoors, escalate privileges, and potentially gain access to sensitive authentication databases that store user credentials and authentication tokens.
Mitigation strategies for CVE-2015-2281 should prioritize immediate implementation of Fortinet's official security patches and firmware updates that address the buffer overflow condition in collectoragent.exe. Network segmentation and firewall rules should be implemented to restrict access to TCP port 8000, limiting exposure to trusted network segments only. Security monitoring should be enhanced to detect anomalous PROCESS_HELLO message patterns and unusual traffic volumes on the affected port. Organizations should also consider implementing intrusion detection systems with signature-based detection capabilities for this specific vulnerability. The ATT&CK framework categorizes this vulnerability under T1059 for execution and T1078 for valid accounts, emphasizing the need for comprehensive monitoring of authentication service behavior and user account activities. Regular security assessments and vulnerability scanning should be conducted to identify any remaining instances of vulnerable FSSO implementations within the organization's infrastructure.