CVE-2017-8790 in FTA
Summary
by MITRE
An issue was discovered on Accellion FTA devices before FTA_9_12_180. The home/seos/courier/ldaptest.html POST parameter "filter" can be used for LDAP Injection.
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Analysis
by VulDB Data Team • 09/24/2020
The vulnerability identified as CVE-2017-8790 affects Accellion FTA (File Transfer Appliance) devices running versions prior to FTA_9_12_180. This represents a critical security flaw that allows unauthorized users to manipulate LDAP (Lightweight Directory Access Protocol) queries through a specifically targeted input parameter. The vulnerability exists within the home/seos/courier/ldaptest.html web interface component where the filter parameter is processed without adequate sanitization or validation, creating a pathway for malicious input to be interpreted as part of the LDAP query structure rather than as data.
The technical implementation of this vulnerability stems from improper input handling within the LDAP testing functionality of the Accellion appliance. When users submit requests containing malicious content in the filter parameter, the system fails to properly escape or sanitize special LDAP metacharacters such as parentheses, asterisks, or comparison operators. This allows attackers to inject arbitrary LDAP filter syntax that can manipulate the underlying directory service queries, potentially enabling them to bypass authentication mechanisms, access unauthorized directory entries, or perform additional malicious operations against the LDAP infrastructure. The vulnerability directly maps to CWE-91, which specifically addresses improper neutralization of special elements used in LDAP queries, and represents a classic example of LDAP injection as defined in the OWASP Top Ten security risks.
The operational impact of this vulnerability extends beyond simple data access violations, as it can enable attackers to gain unauthorized access to sensitive directory information and potentially escalate privileges within the affected system. Attackers could leverage this weakness to perform reconnaissance activities against the LDAP directory service, extract user credentials, or manipulate directory entries to gain persistence within the environment. The vulnerability's exploitation does not require authentication for the initial attack vector, making it particularly dangerous as it can be exploited by any remote user who can access the vulnerable web interface. This weakness creates a significant risk for organizations relying on Accellion FTA appliances for secure file transfers, as it undermines the integrity of the directory services that these appliances depend upon for authentication and authorization processes.
Organizations should immediately implement mitigations including updating to the patched version FTA_9_12_180 or later, which contains proper input validation and sanitization mechanisms for the LDAP filter parameter. Network segmentation and access controls should be strengthened to limit exposure of the vulnerable web interface to untrusted networks, while monitoring systems should be configured to detect suspicious LDAP query patterns. Security teams should also conduct thorough assessments of their directory service configurations to ensure that the compromised appliance does not provide unauthorized access to sensitive data or systems. The vulnerability demonstrates the critical importance of input validation in web applications and highlights the risks associated with insufficient sanitization of user-supplied data in security-critical components, particularly those that interact with backend directory services. This issue aligns with ATT&CK technique T1078 which covers valid accounts and credential access, as successful exploitation could lead to unauthorized access to directory services and associated credentials.