CVE-2019-7250 in Cross Reference Add-on
Summary
by MITRE
An issue was discovered in the Cross Reference Add-on 36 for Google Docs. Stored XSS in the preview boxes in the configuration panel may allow a malicious user to use both label text and references text to inject arbitrary JavaScript code (via SCRIPT elements, event handlers, etc.). Since this code is stored by the plugin, the attacker may be able to target anyone who opens the configuration panel of the plugin.
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Analysis
by VulDB Data Team • 07/04/2023
The vulnerability identified as CVE-2019-7250 resides within the Cross Reference Add-on 36 for Google Docs, representing a critical stored cross-site scripting flaw that compromises user security within the Google Workspace environment. This vulnerability specifically affects the preview functionality within the plugin's configuration panel, where user input is not properly sanitized or validated before being rendered back to users. The flaw allows attackers to inject malicious JavaScript code through carefully crafted label text and reference text fields, creating a persistent threat that remains active until the affected plugin is updated or uninstalled.
The technical exploitation of this vulnerability occurs through the manipulation of input fields within the plugin's configuration interface. When users view the preview boxes containing maliciously crafted content, the stored JavaScript code executes within the context of the Google Docs application, potentially compromising the user's session and browser environment. The vulnerability stems from insufficient input validation and output encoding mechanisms that fail to properly escape special characters and script tags in user-provided content. This stored XSS vulnerability operates at the application layer and leverages the trust relationship between the user and the Google Docs platform, allowing attackers to execute arbitrary code with the privileges of the victim user.
The operational impact of CVE-2019-7250 extends beyond simple code execution, as it creates a persistent threat vector that can affect multiple users within an organization. Once an attacker successfully injects malicious code into the plugin's configuration panel, any user who accesses that configuration interface becomes a potential victim. This makes the vulnerability particularly dangerous in enterprise environments where multiple users may interact with the same Google Docs documents and plugin configurations. The attack can lead to session hijacking, data exfiltration, credential theft, and potentially broader system compromise through the execution of additional malicious payloads. The stored nature of the vulnerability means that the threat persists even after the initial injection, continuously targeting users who encounter the compromised content.
Mitigation strategies for CVE-2019-7250 should focus on immediate plugin updates from the vendor, as well as implementing additional security controls within the organization's Google Workspace environment. Organizations should enforce strict access controls over plugin installations and configurations, limiting the ability of users to modify plugin settings to authorized personnel only. Network-level protections such as content security policies and web application firewalls can provide additional layers of defense against exploitation attempts. Regular security assessments of third-party plugins and extensions should be conducted to identify similar vulnerabilities, with particular attention to input validation mechanisms and output encoding practices. The vulnerability aligns with CWE-79, which describes cross-site scripting flaws, and may be mapped to ATT&CK techniques involving client-side exploitation and credential access through compromised user sessions. Organizations should also consider implementing user education programs to raise awareness about the risks of interacting with untrusted plugin configurations and the importance of keeping software components updated.