CVE-2019-15709 in FortiAP-S-W2
Summary
by MITRE
An improper input validation in FortiAP-S/W2 6.2.0 to 6.2.2, 6.0.5 and below, FortiAP-U 6.0.1 and below CLI admin console may allow unauthorized administrators to overwrite system files via specially crafted tcpdump commands in the CLI.
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Analysis
by VulDB Data Team • 06/02/2020
This vulnerability resides in the command line interface of FortiAP wireless access points, specifically affecting firmware versions 6.2.0 through 6.2.2 for FortiAP-S/W2 models and 6.0.5 and earlier for FortiAP-U models. The flaw represents a critical input validation weakness that enables unauthorized administrative users to execute malicious commands through crafted tcpdump operations within the CLI environment. The vulnerability stems from insufficient sanitization of user inputs passed to system commands, creating a path for command injection attacks that can escalate privileges and compromise system integrity.
The technical implementation of this vulnerability involves the improper handling of user-supplied arguments in tcpdump command execution within the FortiAP CLI. When administrators execute tcpdump commands through the interface, the system fails to properly validate or sanitize the input parameters, allowing attackers to inject malicious commands that bypass normal access controls. This weakness directly maps to CWE-77 and CWE-89, representing command injection vulnerabilities that allow arbitrary code execution. The attack vector specifically targets the CLI administrative interface where legitimate administrative users can potentially be tricked into executing compromised commands, or where unauthorized users can gain administrative access through other means and then exploit this vulnerability.
The operational impact of this vulnerability extends beyond simple privilege escalation, as it enables attackers to overwrite critical system files and potentially gain root-level access to the device. This could result in complete device compromise, allowing attackers to modify firmware, install backdoors, or redirect network traffic through the compromised access point. The vulnerability affects wireless network infrastructure components that are often deployed in sensitive environments, making the potential impact substantial for organizations relying on Fortinet's wireless solutions. Network attackers could leverage this vulnerability to establish persistent access points within wireless networks, potentially enabling further lateral movement and data exfiltration activities.
Mitigation strategies should focus on immediate firmware updates to versions that address the input validation flaws, as well as implementing network segmentation to limit access to administrative interfaces. Organizations should also enforce strict access controls and monitoring of CLI activities, particularly around tcpdump and other network analysis commands. The vulnerability aligns with ATT&CK technique T1059.001 for command and scripting interpreter, and T1068 for exploit for privilege escalation. Administrators should consider implementing network access controls to restrict CLI access to trusted administrative workstations and establish logging requirements for all CLI activities to detect potential exploitation attempts. Regular security assessments of wireless infrastructure components are essential to identify similar input validation weaknesses in other network devices that may be vulnerable to similar attacks.