CVE-2020-27659 in SafeAccess
Summary
by MITRE • 11/30/2020
Multiple cross-site scripting (XSS) vulnerabilities in Synology SafeAccess before 1.2.3-0234 allow remote attackers to inject arbitrary web script or HTML via the (1) domain or (2) profile parameter.
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Analysis
by VulDB Data Team • 12/11/2020
The vulnerability identified as CVE-2020-27659 represents a critical cross-site scripting flaw within Synology SafeAccess software version 1.2.2 and earlier. This vulnerability affects the authentication and access management system that Synology provides for enterprise environments, specifically targeting the web interface components that handle domain and profile parameters. The issue stems from insufficient input validation and output encoding mechanisms within the application's user interface, creating opportunities for malicious actors to execute arbitrary scripts in the context of authenticated users' browsers.
The technical exploitation of this vulnerability occurs through manipulation of the domain or profile parameters in the web application's request handling mechanism. When users interact with the SafeAccess interface and provide input through these parameters, the application fails to properly sanitize or encode the data before rendering it in the browser context. This creates an environment where attackers can inject malicious JavaScript code that executes within the victim's browser session, potentially compromising user credentials, session tokens, or other sensitive information. The vulnerability is classified under CWE-79 as a failure to sanitize user input, specifically manifesting as cross-site scripting in web applications.
The operational impact of this vulnerability extends beyond simple script injection, as it can enable attackers to perform session hijacking, credential theft, and privilege escalation within the affected environment. An attacker who successfully exploits this vulnerability can manipulate the SafeAccess interface to redirect users to malicious websites, steal authentication tokens, or inject additional malicious code that persists across user sessions. Given that SafeAccess is designed for enterprise environments where users may have elevated privileges or access to sensitive systems, the potential for lateral movement and data exfiltration increases significantly. The vulnerability also aligns with ATT&CK technique T1566.001, which describes social engineering through malicious web content, and T1071.001, which covers application layer protocol usage for command and control.
Mitigation strategies for CVE-2020-27659 primarily involve immediate software updates to version 1.2.3-0234 or later, which contain proper input validation and output encoding fixes. Organizations should also implement additional security measures including web application firewalls, input validation rules, and regular security assessments of the SafeAccess environment. Network segmentation and monitoring for suspicious parameter manipulation attempts can help detect exploitation attempts. The vulnerability demonstrates the importance of implementing defense-in-depth strategies, as proper input sanitization and output encoding should be implemented at multiple layers of the application architecture. Security teams should also conduct regular penetration testing and vulnerability assessments to identify similar issues in other enterprise applications that may be vulnerable to similar cross-site scripting attacks.