CVE-2018-6824 in Cozy
Summary
by MITRE
Cozy has XSS allowing remote attackers to obtain administrative access via JavaScript code in the url parameter to the /api/proxy URI, as demonstrated by an XMLHttpRequest call with an 'email:"[email protected]"' request, which can be followed by a password reset.
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Analysis
by VulDB Data Team • 01/02/2020
The vulnerability identified as CVE-2018-6824 represents a critical cross-site scripting flaw within the Cozy platform that enables remote attackers to escalate privileges and gain administrative access. This vulnerability specifically targets the /api/proxy URI endpoint where the application fails to properly sanitize user input from URL parameters, creating an exploitable vector for malicious JavaScript code execution. The flaw manifests when an attacker crafts a malicious URL containing JavaScript payload in the url parameter, which then gets executed within the context of the victim's browser session. This type of vulnerability falls under CWE-79 - Improper Neutralization of Input During Web Page Generation, which is a fundamental weakness in web application security where input is not properly escaped or validated before being rendered in web pages.
The operational impact of this vulnerability extends beyond simple XSS exploitation as it provides attackers with a pathway to administrative compromise through a sophisticated attack chain. The demonstration shows how an attacker can leverage XMLHttpRequest to send a request with an email parameter containing the attacker's email address, effectively allowing them to initiate a password reset process for the targeted account. This attack vector specifically targets the authentication and session management mechanisms of the Cozy platform, potentially enabling complete account takeover and administrative privilege escalation. The vulnerability is particularly dangerous because it does not require any prior authentication or session information from the victim, making it a server-side attack that can be executed entirely through crafted web requests.
From a cybersecurity perspective, this vulnerability aligns with ATT&CK technique T1059.007 - Command and Scripting Interpreter: JavaScript, which describes how adversaries can leverage JavaScript execution capabilities to perform malicious activities within web applications. The attack chain demonstrates the exploitation of input validation weaknesses to achieve privilege escalation, which is consistent with ATT&CK tactic TA0004 - Privilege Escalation. The vulnerability's impact is further amplified by the fact that it operates at the API layer, making it particularly effective for bypassing traditional client-side security controls and directly targeting the application's backend functionality. The use of XMLHttpRequest in the demonstration indicates that attackers can leverage modern web technologies to create sophisticated attacks that appear legitimate to the target application's security controls.
The remediation approach for this vulnerability requires comprehensive input validation and output encoding at the application level, specifically implementing proper sanitization of all user-provided parameters before they are processed or rendered. Organizations should implement Content Security Policy (CSP) headers to prevent unauthorized script execution and employ proper parameter validation techniques to ensure that URL parameters are properly escaped before being used in API calls. Additionally, the application should implement proper session management controls and authentication mechanisms to prevent unauthorized access even if an XSS attack is successfully executed. The vulnerability highlights the importance of implementing defense-in-depth strategies that combine multiple security controls to protect against similar classes of attacks, including regular security testing, automated input validation, and proper error handling to prevent information leakage that could aid attackers in crafting more sophisticated exploits.