CVE-2017-5246 in Secure File Transfer
Summary
by MITRE
Biscom Secure File Transfer is vulnerable to AngularJS expression injection in the Display Name field. An authenticated user can populate this field with a valid AngularJS expression, wrapped in double curly-braces ({{ }}). This expression will be evaluated by any other authenticated user who views the attacker's display name.
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Analysis
by VulDB Data Team • 01/01/2021
The vulnerability identified as CVE-2017-5246 affects Biscom Secure File Transfer software, a solution designed for secure file exchange within enterprise environments. This weakness represents a critical security flaw that undermines the integrity of user authentication and data protection mechanisms. The vulnerability specifically resides in the handling of user display names within the application's user interface components, creating a potential vector for malicious code execution and information disclosure.
The technical flaw manifests through improper input validation and sanitization of the Display Name field within the AngularJS-based web interface. When an authenticated attacker inputs a malicious AngularJS expression enclosed in double curly braces {{ }}, the application fails to properly escape or filter this content. The AngularJS framework, designed to facilitate dynamic web applications, processes these expressions during rendering, leading to arbitrary code execution within the context of other authenticated users' browsers. This represents a classic server-side template injection vulnerability that leverages client-side rendering mechanisms.
The operational impact of this vulnerability extends beyond simple privilege escalation, as it enables attackers to manipulate the application's behavior and potentially access sensitive user data. Any authenticated user who views the malicious display name will have the injected AngularJS code executed in their browser context, potentially allowing for session hijacking, data exfiltration, or further exploitation of the victim's privileges. The attack requires only basic authentication access to the system, making it particularly dangerous in environments where user access controls are not properly enforced. This vulnerability directly aligns with CWE-79 which describes improper neutralization of input during web page generation, specifically in the context of client-side template injection.
The security implications of CVE-2017-5246 align with several techniques documented in the MITRE ATT&CK framework, particularly those related to credential access and execution. The vulnerability enables adversaries to establish persistent access through session manipulation and can be leveraged for information gathering activities. The attack vector demonstrates characteristics of privilege escalation through code injection, where a user with minimal privileges can exploit the system to gain access to other users' data and sessions. Organizations utilizing Biscom Secure File Transfer must consider this vulnerability as part of their broader security posture assessment, particularly in environments where sensitive data is handled.
Mitigation strategies should include immediate implementation of input sanitization and output encoding for all user-controllable fields within the application. The AngularJS framework should be configured with proper security settings to prevent expression evaluation in user-provided content, including the implementation of Content Security Policy headers to restrict script execution. Organizations should also consider implementing additional access controls and monitoring mechanisms to detect unusual patterns of display name modifications. The vulnerability underscores the importance of proper input validation and output encoding practices in web applications, particularly those utilizing dynamic template rendering frameworks. Regular security assessments and penetration testing should be conducted to identify similar vulnerabilities in other components of the application stack.