CVE-2017-8793 in FTA
Summary
by MITRE
An issue was discovered on Accellion FTA devices before FTA_9_12_180. By sending a POST request to home/seos/courier/web/wmProgressstat.html.php with an attacker domain in the acallow parameter, the device will respond with an Access-Control-Allow-Origin header allowing the attacker to have site access with a bypass of the Same Origin Policy.
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Analysis
by VulDB Data Team • 09/24/2020
The vulnerability identified as CVE-2017-8793 affects Accellion FTA (File Transfer Appliance) devices running versions prior to FTA_9_12_180, representing a critical cross-origin resource sharing misconfiguration that fundamentally undermines web application security controls. This issue stems from improper handling of the Access-Control-Allow-Origin header within the device's web interface, specifically in the wmProgressstat.html.php endpoint located at home/seos/courier/web/. The vulnerability manifests when an attacker crafts a malicious POST request that includes an arbitrary domain in the acallow parameter, thereby manipulating the device's response headers to grant unauthorized cross-origin access.
The technical flaw resides in the device's failure to properly validate and sanitize input parameters, particularly the acallow parameter that controls CORS behavior. When processed, this parameter directly influences the Access-Control-Allow-Origin header returned in HTTP responses, creating an opportunity for attackers to inject malicious domains and bypass the browser's Same Origin Policy. This misconfiguration allows attackers to perform cross-site scripting attacks, data exfiltration, and potentially gain unauthorized access to sensitive information within the device's administrative interface. The vulnerability operates at the application layer and can be exploited without requiring authentication, making it particularly dangerous as it can be leveraged by remote attackers with minimal privileges.
The operational impact of this vulnerability extends beyond simple data theft, as it enables sophisticated attack vectors that can compromise the entire security posture of the affected system. Attackers can leverage this vulnerability to perform man-in-the-middle attacks, steal session cookies, access administrative functions, and potentially escalate privileges within the device environment. The Same Origin Policy bypass creates a pathway for attackers to execute malicious scripts against authenticated users, leading to potential account takeovers and persistent access to the device. This vulnerability affects organizations using Accellion FTA appliances for secure file transfer operations, potentially exposing sensitive corporate data and violating regulatory compliance requirements for data protection and network security.
Organizations should implement immediate mitigations including upgrading to FTA_9_12_180 or later versions that address this CORS misconfiguration, implementing proper input validation and sanitization controls, and configuring network-level restrictions to limit access to the vulnerable endpoints. The vulnerability aligns with CWE-346, which addresses "Origin Validation Error" in web applications, and can be categorized under ATT&CK technique T1071.004 for application layer protocol manipulation. Network segmentation and firewall rules should be implemented to restrict direct access to the vulnerable web interface, while security monitoring should be enhanced to detect anomalous CORS header behavior. Additionally, organizations should conduct comprehensive security assessments of their web applications and ensure proper CORS policy implementation that validates and restricts origins to legitimate domains only, preventing similar vulnerabilities from emerging in other components of their infrastructure.