CVE-2017-16775 in SSO Server
Summary
by MITRE
Improper restriction of rendered UI layers or frames vulnerability in SSOOauth.cgi in Synology SSO Server before 2.1.3-0129 allows remote attackers to conduct clickjacking attacks via unspecified vectors.
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Analysis
by VulDB Data Team • 08/21/2023
The vulnerability identified as CVE-2017-16775 represents a critical improper restriction of rendered UI layers or frames flaw within the Synology SSO Server component SSOOauth.cgi. This issue affects versions prior to 2.1.3-0129 and creates a significant security risk by enabling remote attackers to execute clickjacking attacks through unspecified vectors. The vulnerability stems from inadequate protection mechanisms that fail to properly control the rendering behavior of user interface elements, specifically within the single sign-on authentication framework. Attackers can exploit this weakness by crafting malicious web pages that overlay legitimate authentication interfaces, deceiving users into performing unintended actions while believing they are interacting with legitimate system components.
The technical nature of this vulnerability aligns with CWE-1021, which specifically addresses improper restriction of rendered UI layers or frames, making it a direct implementation of this well-documented security weakness. The flaw manifests when the SSOOauth.cgi script fails to implement proper security measures such as X-Frame-Options headers or Content Security Policy directives that would prevent the page from being embedded within other frames or layers. This allows malicious actors to create deceptive user interfaces where legitimate authentication prompts appear to be part of a trusted application while actually being controlled by an attacker's malicious content. The vulnerability operates at the presentation layer of the application, exploiting the trust relationship between the user and the authentication interface.
The operational impact of this vulnerability extends beyond simple session hijacking, as it provides attackers with a sophisticated vector for conducting various forms of social engineering attacks. Remote attackers can leverage this weakness to manipulate users into submitting credentials, performing administrative actions, or executing other sensitive operations without proper authorization. The clickjacking attack vector is particularly dangerous because it can bypass traditional authentication mechanisms and user awareness techniques, as users may not realize they are interacting with a maliciously crafted interface. This vulnerability essentially undermines the fundamental security principle of user interface integrity by allowing unauthorized overlay of critical authentication components.
Mitigation strategies for CVE-2017-16775 should focus on implementing proper frame restriction mechanisms and ensuring that all authentication interfaces are protected against embedding. The most effective solution involves deploying X-Frame-Options headers with the value SAMEORIGIN or DENY to prevent the SSO authentication pages from being rendered within frame elements of other domains. Additionally, implementing Content Security Policy directives with frame-ancestors restrictions provides an additional layer of protection against clickjacking attacks. Organizations should also consider updating to Synology SSO Server version 2.1.3-0129 or later, which includes patches addressing this specific vulnerability. Security teams should conduct comprehensive assessments of their authentication interfaces to identify any other potential clickjacking vulnerabilities and ensure that all web applications implement proper frame protection mechanisms as recommended by the OWASP Top Ten project and the NIST Cybersecurity Framework.