CVE-2017-20119 in Server
Summary
by MITRE • 06/29/2022
A vulnerability classified as problematic has been found in TrueConf Server 4.3.7. This affects an unknown part of the file /admin/general/change-lang. The manipulation of the argument redirect_url leads to open redirect. It is possible to initiate the attack remotely. The exploit has been disclosed to the public and may be used.
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Analysis
by VulDB Data Team • 03/24/2023
This vulnerability resides within TrueConf Server version 4.3.7 and specifically targets the administrative interface component located at /admin/general/change-lang. The flaw manifests as an open redirect vulnerability that occurs when processing the redirect_url parameter within the file path. The vulnerability allows an attacker to manipulate the redirect_url argument in a way that can cause the application to redirect users to arbitrary external domains. This type of vulnerability falls under CWE-601 which specifically addresses open redirect vulnerabilities in web applications. The attack vector is remote, meaning that an adversary can exploit this weakness without requiring physical access to the system or direct network connection to the server.
The technical implementation of this vulnerability involves the application's failure to properly validate or sanitize user-supplied input when processing the redirect_url parameter. When a user accesses the administrative change-lang endpoint with a malicious redirect_url value, the server accepts this input without adequate verification and subsequently uses it to perform an HTTP redirect operation. This behavior creates a pathway for attackers to craft deceptive redirects that can be used for phishing attacks, credential harvesting, or social engineering campaigns. The vulnerability represents a classic example of insufficient input validation and output encoding practices that are fundamental to secure web application development.
The operational impact of this vulnerability extends beyond simple redirection, as it can be leveraged as a stepping stone for more sophisticated attacks within the context of a broader security compromise. An attacker could potentially redirect authenticated users to malicious domains where they might be prompted to enter credentials or download malware, effectively using the legitimate TrueConf Server as a conduit for malicious activity. This vulnerability also aligns with ATT&CK technique T1566 which covers social engineering tactics involving phishing and deceptive redirects. The public disclosure of this exploit increases the risk profile significantly, as it provides threat actors with a readily available tool for targeting TrueConf Server installations.
Mitigation strategies for this vulnerability should focus on implementing proper input validation and sanitization for all user-supplied parameters, particularly those used in redirect operations. The most effective approach involves validating that redirect URLs conform to a whitelist of trusted domains or implementing strict URL validation that prevents redirection to external domains. Organizations should also consider implementing proper HTTP headers such as X-Frame-Options and Content Security Policy to limit the potential impact of any successful redirect attacks. Additionally, regular security assessments and vulnerability scanning should be conducted to identify similar weaknesses in other components of the TrueConf Server installation. The vulnerability demonstrates the critical importance of secure coding practices and proper parameter validation in web applications, particularly in administrative interfaces where privileged access can be leveraged to cause broader system compromise.