CVE-2018-18524 in Evernote
Summary
by MITRE
Evernote 6.15 on Windows has an incorrectly repaired stored XSS vulnerability. An attacker can use this XSS issue to inject Node.js code under Present mode. After a victim opens an affected note under Present mode, the attacker can read the victim's files and achieve remote execution command on the victim's computer.
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Analysis
by VulDB Data Team • 09/15/2023
The vulnerability CVE-2018-18524 represents a critical stored cross-site scripting flaw in Evernote version 6.15 for Windows operating systems. This security weakness stems from an improper remediation of a previously identified XSS vulnerability, creating a persistent security gap that allows attackers to execute malicious code through seemingly benign note content. The flaw specifically manifests when users open affected notes in Present mode, a feature designed for presentation and sharing purposes within the Evernote application.
The technical implementation of this vulnerability involves the improper sanitization of user input within note content, particularly when processing HTML elements and JavaScript code. When an attacker crafts a malicious note containing encoded Node.js code within the stored content, the vulnerability allows this code to execute within the application's context during presentation mode. The flaw operates under CWE-79 which categorizes cross-site scripting vulnerabilities as weaknesses in input validation and output encoding. This particular implementation demonstrates how inadequate remediation of security issues can create new attack vectors rather than closing existing ones.
The operational impact of this vulnerability extends far beyond simple script execution, as it enables full remote code execution capabilities on compromised systems. Once a victim opens the malicious note in Present mode, the attacker gains access to read arbitrary files from the victim's local system, potentially accessing sensitive documents, personal data, or confidential business information. The remote command execution capability provides attackers with persistent access to the compromised machine, allowing them to install additional malware, establish backdoors, or perform further reconnaissance activities. This vulnerability directly aligns with ATT&CK technique T1059 which covers command and scripting interpreter usage, and T1074 which covers data staging through local data staging.
Mitigation strategies for CVE-2018-18524 should prioritize immediate patching of the Evernote application to the latest secure version that properly addresses the XSS vulnerability. Organizations should implement network-based security controls including web application firewalls and content filtering systems to prevent malicious note content from being processed within their environments. Additionally, user education regarding the risks of opening untrusted notes in presentation mode and implementing strict access controls for note sharing can significantly reduce exploitation success rates. Security monitoring should include detection of unusual file access patterns and command execution activities that may indicate exploitation of this vulnerability. The incident highlights the critical importance of proper vulnerability remediation and comprehensive security testing before releasing software updates to prevent regressions that create new attack surfaces.