CVE-2018-9846 Explained : Impact and Mitigation

A vulnerability in the Roundcube email client versions 1.2.0 to 1.3.5 allows attackers to perform an MX (IMAP) injection attack through the archive plugin.

Understanding CVE-2018-9846

What is CVE-2018-9846?

In Roundcube versions 1.2.0 to 1.3.5, a vulnerability exists in the archive plugin that can be exploited by manipulating the "_uid" parameter in a specific request.

The Impact of CVE-2018-9846

This vulnerability enables attackers to execute an MX (IMAP) injection attack, potentially compromising the integrity of the email system.

Technical Details of CVE-2018-9846

Vulnerability Description

The vulnerability arises when the archive plugin is enabled and configured, allowing attackers to insert malicious IMAP commands.

Affected Systems and Versions

Versions 1.2.0 to 1.3.5 of Roundcube

Exploitation Mechanism

Attackers manipulate the "_uid" parameter in a request to archive.php
By inserting an IMAP command after a specific sequence, an MX (IMAP) injection attack can be executed
Exploitation is more challenging in version 1.3.4 and later due to enhanced security measures

Mitigation and Prevention

Immediate Steps to Take

Disable the archive plugin if not essential
Implement input validation to sanitize user-controlled parameters
Regularly monitor and analyze IMAP traffic for suspicious activities

Long-Term Security Practices

Keep Roundcube updated to the latest version
Educate users on email security best practices

Patching and Updates

Apply patches provided by Roundcube to address the vulnerability