Roundcube XSS Flaw Allows Attackers to Inject Malicious Files

A critical Cross-Site Scripting (XSS) vulnerability has been discovered in the popular open-source webmail client, Roundcube, potentially exposing users to serious security risks.

Tracked as CVE-2024-57004, the flaw affects Roundcube Webmail version 1.6.9 and allows remote authenticated users to upload malicious files disguised as email attachments.

Once the malicious file is uploaded, the vulnerability can be triggered when the victim accesses their “SENT” folder.

Vulnerability Details

According to the published CVE entry, the vulnerability originates from insufficient sanitization of user input when handling email attachments.

This oversight permits attackers to inject malicious scripts into files uploaded as attachments.

When a user unknowingly accesses their Sent folder where the compromised email resides, the embedded script executes in their browser, potentially granting attackers unauthorized access to sensitive data or enabling further exploitation.

The flaw is particularly dangerous given that it requires minimal interaction from the victim. The attacker only needs access to an authenticated account in the system to craft and send the malicious email.

The vulnerability impacts systems using the affected version of Roundcube deployed in corporate environments, educational institutions, and personal email setups.

An attack leveraging this XSS vulnerability could have widespread implications, including:

1. Data Theft: Attackers could steal sensitive information such as login credentials, email content, or personal data stored in the victim’s browser session.
2. Account Compromise: The vulnerability may enable attackers to hijack email accounts or gain unauthorized access to email servers.
3. Spread of Malware: By injecting malicious files, attackers can propagate malware to other systems connected to the Roundcube deployment.

The Roundcube development team acknowledged the vulnerability and has released a security patch addressing the issue in version 1.6.10.

Administrators and users are strongly advised to update their Roundcube installations immediately.

The patch ensures stricter input validation during file uploads, mitigating the risk of XSS. To protect against potential exploitation of CVE-2024-57004, users are urged to:

1. Upgrade to Roundcube 1.6.10 or Later: Install the latest version of Roundcube to mitigate the vulnerability.
2. Apply Security Best Practices: Limit user access permissions and employ web application firewalls (WAFs) to detect and block malicious payloads.
3. Monitor For Unusual Activity: Regularly review webmail activity logs for potential signs of exploitation.

This latest discovery highlights the importance of staying vigilant and maintaining up-to-date software to reduce exposure to security risks.

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