CVE-2016-8505 in Javascript
Summary
by MITRE
XSS in Yandex Browser BookReader in Yandex browser for desktop for versions before 16.6. could be used by remote attacker for evaluation arbitrary javascript code.
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Analysis
by VulDB Data Team • 05/19/2019
The vulnerability identified as CVE-2016-8505 represents a cross-site scripting flaw within the BookReader component of the Yandex Browser desktop application. This security weakness affects versions prior to 16.6 and creates a significant risk for users who may inadvertently encounter malicious content while browsing. The flaw allows remote attackers to inject and execute arbitrary javascript code through manipulated book reading content, potentially compromising user systems and data integrity.
The technical implementation of this vulnerability stems from insufficient input validation and output encoding within the BookReader module. When the browser processes certain book-related content, it fails to properly sanitize user-supplied data before rendering it in the browser interface. This inadequate sanitization creates an opening for attackers to craft malicious payloads that exploit the browser's rendering engine. The vulnerability specifically manifests when the browser encounters specially crafted book metadata or content that includes embedded javascript code, which then executes in the context of the user's browsing session.
The operational impact of CVE-2016-8505 extends beyond simple script execution, as it provides attackers with the capability to perform various malicious activities. An attacker could leverage this vulnerability to steal user session cookies, redirect users to malicious websites, or even download and execute additional malware. The remote nature of the attack means that users do not need to perform any specific actions beyond visiting compromised websites or opening malicious book files. This makes the vulnerability particularly dangerous as it can be exploited through various attack vectors including compromised websites, malicious advertisements, or even legitimate content that has been tampered with.
From a cybersecurity framework perspective, this vulnerability aligns with CWE-79 - Cross-site Scripting, which specifically addresses the improper handling of user-supplied input in web applications and browser environments. The attack pattern follows typical XSS exploitation techniques documented in the MITRE ATT&CK framework under the technique T1059.007 - Command and Scripting Interpreter: JavaScript, where attackers leverage browser-based scripting capabilities to execute malicious code. The vulnerability also demonstrates characteristics consistent with T1566 - Phishing, as attackers can use this flaw to craft convincing phishing attacks that appear legitimate but execute malicious code when users interact with the content.
Mitigation strategies for CVE-2016-8505 primarily focus on immediate software updates and user education. Users should immediately upgrade to Yandex Browser version 16.6 or later, which contains the necessary patches to address the input validation issues. Organizations should implement network-based protections including web application firewalls and content filtering systems that can detect and block malicious script injection attempts. Additionally, security awareness training should emphasize the importance of avoiding untrusted websites and suspicious book-related content. Browser security configurations should be reviewed to ensure proper sandboxing and privilege separation, and users should be encouraged to regularly update their software to protect against known vulnerabilities. The vulnerability also underscores the importance of implementing proper input validation and output encoding mechanisms in all browser components, particularly those handling user-generated content or external data sources.