CVE-2017-1000051 in CryptPad
Summary
by MITRE
Cross-site scripting (XSS) vulnerability in pad export in XWiki labs CryptPad before 1.1.1 allows remote attackers to inject arbitrary web script or HTML via the pad content
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Analysis
by VulDB Data Team • 12/12/2022
The vulnerability identified as CVE-2017-1000051 represents a critical cross-site scripting flaw within the XWiki labs CryptPad application's pad export functionality. This security weakness affects versions prior to 1.1.1 and enables remote attackers to execute malicious web scripts or HTML code through manipulated pad content. The vulnerability resides in the export mechanism where user-generated content is processed and rendered without adequate input sanitization or output encoding. The affected component specifically handles the export of collaborative pads, which are web-based documents used for real-time editing and sharing within the XWiki ecosystem. Attackers can exploit this vulnerability by crafting malicious content within a pad that, when exported, executes arbitrary scripts in the context of other users who view the exported content.
The technical exploitation of this XSS vulnerability occurs when users interact with exported pad content that contains malicious script payloads. The flaw demonstrates characteristics of CWE-79 - Improper Neutralization of Input During Web Page Generation, where input data fails to be properly sanitized before being incorporated into web pages. The vulnerability operates under the principle that user input from pad content is directly embedded into exported HTML without appropriate context-aware encoding or validation. This allows attackers to inject script tags, event handlers, or other malicious HTML elements that execute in the browser context of victims. The attack vector is particularly concerning because it leverages legitimate application functionality rather than requiring direct access to system resources or privileged accounts.
The operational impact of this vulnerability extends beyond simple script execution, potentially enabling sophisticated attack chains that could lead to session hijacking, credential theft, or further exploitation of the target environment. When users view exported pads containing malicious code, their browsers execute the injected scripts in the context of their authenticated sessions, potentially allowing attackers to steal cookies, access sensitive information, or perform actions on behalf of victims. This vulnerability affects the core collaborative features of the platform, making it particularly dangerous in environments where multiple users share documents and collaborate in real-time. The risk is amplified because the attack requires minimal privileges and can be executed through standard web interactions with exported content, making it accessible to attackers with basic web security knowledge.
Mitigation strategies for CVE-2017-1000051 should prioritize immediate application updates to version 1.1.1 or later, which includes proper input sanitization and output encoding mechanisms. Organizations should implement comprehensive content security policies that restrict script execution in exported content and enforce strict validation of all user inputs. The implementation of CSP headers can provide additional protection layers against script execution, while regular security audits of export functionality should be conducted to identify similar vulnerabilities. Security teams should also consider implementing web application firewalls that can detect and block suspicious content patterns in exported documents, and establish monitoring procedures for unusual activity related to pad exports. The vulnerability highlights the importance of input validation and output encoding practices in web applications, aligning with ATT&CK technique T1213 - Data from Information Repositories, where attackers may exploit such vulnerabilities to access sensitive data through crafted content.
The vulnerability demonstrates how collaborative web applications face unique security challenges when processing user-generated content that may be exported and shared across different contexts. The flaw underscores the need for defense-in-depth strategies that protect not just the application's core functionality but also its export mechanisms and content sharing features. Organizations using similar collaborative platforms should conduct thorough vulnerability assessments to identify and remediate comparable XSS vulnerabilities in their own systems. This particular vulnerability serves as a reminder of the critical importance of validating and sanitizing all user inputs, especially in applications where content is shared between multiple users and contexts, as the attack surface expands with each sharing mechanism. The security implications extend beyond immediate exploitation to include potential long-term damage to user trust and platform integrity in collaborative environments.