CVE-2014-9714 in HipHop Virtual Machine
Summary
by MITRE
Cross-site scripting (XSS) vulnerability in the WddxPacket::recursiveAddVar function in HHVM (aka the HipHop Virtual Machine) before 3.5.0 allows remote attackers to inject arbitrary web script or HTML via a crafted string to the wddx_serialize_value function.
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Analysis
by VulDB Data Team • 05/03/2022
The CVE-2014-9714 vulnerability represents a critical cross-site scripting flaw within HHVM's WddxPacket::recursiveAddVar function, affecting versions prior to 3.5.0. This vulnerability resides in the HipHop Virtual Machine's handling of XML data serialization operations, specifically within the wddx_serialize_value function that processes data for web applications. The flaw enables remote attackers to execute malicious scripts in victim browsers through crafted input strings that bypass normal validation mechanisms. The vulnerability stems from insufficient sanitization of user-supplied data during the XML serialization process, creating an attack surface where malicious payloads can be embedded and executed in web contexts.
The technical exploitation of this vulnerability occurs when applications using HHVM process user input through the wddx_serialize_value function without proper input validation. The WddxPacket::recursiveAddVar function fails to adequately escape or sanitize special characters in the serialized XML output, allowing attackers to inject malicious JavaScript code or HTML content. When this malformed data is rendered in web browsers, the injected scripts execute within the context of the victim's session, potentially leading to session hijacking, data theft, or unauthorized actions. The vulnerability is particularly dangerous because it operates at the serialization layer, meaning it can affect any application that relies on HHVM's XML data handling capabilities.
The operational impact of CVE-2014-9714 extends beyond simple XSS execution, as it can facilitate more sophisticated attacks within the context of web applications. Attackers can leverage this vulnerability to steal cookies, modify web page content, redirect users to malicious sites, or perform actions on behalf of authenticated users. The vulnerability affects the core serialization functionality of HHVM, which is widely used in web applications that process XML data, making it a significant threat to applications built on the HipHop Virtual Machine platform. The attack vector requires minimal privileges and can be executed remotely, making it particularly attractive to threat actors seeking to compromise web applications.
Security mitigations for this vulnerability include immediate patching of HHVM installations to version 3.5.0 or later, where the serialization functions have been properly hardened against XSS attacks. Organizations should implement comprehensive input validation and output encoding mechanisms at application layers to provide defense-in-depth against similar vulnerabilities. The CWE-79 classification for this vulnerability aligns with the standard weakness category for cross-site scripting, while the ATT&CK technique T1059.007 covers script injection methods that would be applicable to exploiting this flaw. Additional protective measures include implementing content security policies, using web application firewalls, and conducting regular security assessments of applications utilizing HHVM to identify potential injection points and ensure proper sanitization of user inputs.