CVE-2015-2857 in File Transfer Appliance
Summary
by MITRE
Accellion File Transfer Appliance before FTA_9_11_210 allows remote attackers to execute arbitrary code via shell metacharacters in the oauth_token parameter.
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Analysis
by VulDB Data Team • 07/18/2024
The Accellion File Transfer Appliance represents a critical security vulnerability identified as CVE-2015-2857, which affects versions prior to FTA_9_11_210. This vulnerability manifests as a remote code execution flaw that enables attackers to gain unauthorized system access through manipulation of the oauth_token parameter. The appliance serves as a file transfer solution commonly deployed in enterprise environments for secure data exchange, making this vulnerability particularly concerning for organizations relying on its services. The flaw stems from inadequate input validation mechanisms within the authentication framework, specifically targeting the OAuth token handling process. Attackers can exploit this weakness by injecting shell metacharacters into the oauth_token parameter, effectively bypassing authentication controls and executing arbitrary commands on the underlying system.
The technical exploitation of this vulnerability aligns with CWE-77 and CWE-94 categories, representing command injection flaws that permit attackers to execute operating system commands through improperly sanitized input. This vulnerability operates at the intersection of authentication bypass and code execution, allowing threat actors to leverage the OAuth authentication mechanism as an attack vector rather than a security control. The shell metacharacters injected into the oauth_token parameter can include characters such as semicolons, ampersands, or backticks that are interpreted by the system shell, enabling arbitrary command execution. The vulnerability exists due to insufficient sanitization of user-supplied input before processing within the application's authentication flow, creating a path for malicious actors to escalate privileges and gain full system control.
The operational impact of CVE-2015-2857 extends beyond immediate system compromise to encompass potential data breaches, service disruption, and regulatory compliance violations. Organizations utilizing the Accellion appliance may face unauthorized access to sensitive files, modification of system configurations, and potential lateral movement within network environments. The remote nature of the exploit means attackers can target vulnerable systems without physical access, making detection and prevention more challenging. This vulnerability directly maps to several ATT&CK techniques including T1078 for valid accounts usage, T1059 for command and scripting interpreter, and T1566 for phishing with malicious attachments. The attack surface is particularly dangerous in environments where the appliance handles confidential data such as healthcare records, financial information, or intellectual property.
Mitigation strategies for this vulnerability require immediate patching to the FTA_9_11_210 version or subsequent releases that address the input validation flaws. Organizations should implement network segmentation to limit access to the appliance, deploy intrusion detection systems to monitor for suspicious parameter injection attempts, and conduct thorough security assessments of all authentication mechanisms. Additional protective measures include implementing web application firewalls to filter malicious input, enforcing strict input validation rules, and establishing monitoring procedures for unusual authentication patterns. Security teams should also consider implementing multi-factor authentication and privilege least privilege principles to minimize the potential impact of successful exploitation. Regular security audits and vulnerability assessments should be conducted to identify similar input validation weaknesses in other systems and applications, ensuring comprehensive protection against command injection attacks.