In September 2024, cybersecurity experts at Positive Technologies uncovered a sophisticated attack targeting a state organization in a CIS country. The attack exploited a critical vulnerability (CVE-2024-37383) in the popular Roundcube Webmail client, highlighting the ongoing threats faced by government entities and the importance of timely software updates.
Anatomy of the Attack
The malicious email, devoid of text, contained a hidden attachment that went undetected by the email client. Cybersecurity analysts discovered telltale HTML tags within the email body, incorporating an eval(atob(…)) construct designed to decode and execute JavaScript code. The presence of an attribute with an extra space (attributeName=”href “) was a clear indicator of an attempt to exploit the CVE-2024-37383 vulnerability in Roundcube Webmail.
Understanding CVE-2024-37383
CVE-2024-37383 is a cross-site scripting (XSS) vulnerability that allows attackers to execute arbitrary JavaScript code in the user’s browser. This flaw affects Roundcube versions prior to 1.5.6 and versions 1.6 to 1.6.6. The vulnerability was patched by Roundcube developers on May 19, 2024, emphasizing the critical need for organizations to maintain up-to-date software.
Exploitation Mechanism
The payload embedded in the malicious email attempted to retrieve messages from the mail server using the ManageSieve plugin. Additionally, it injected an authentication form into the HTML page displayed to the user, featuring fields for the Roundcube client username (rcmloginuser) and password (rcmloginpwd). Researchers speculate that this tactic aimed to exploit auto-fill features or trick users into re-entering their credentials under the guise of a necessary re-authentication.
Historical Context and Threat Actors
Roundcube Webmail has been a target for various advanced persistent threat (APT) groups in the past. Notable actors such as APT28, Winter Vivern, and TAG-70 have exploited vulnerabilities in this widely-used email client. However, the current attack has not been definitively linked to any known threat group, underscoring the evolving landscape of cyber threats and the emergence of new or previously unidentified actors.
This incident serves as a stark reminder of the persistent threats facing government organizations and the critical importance of robust cybersecurity measures. It highlights the need for regular security audits, prompt application of software updates, and comprehensive user education to mitigate the risks posed by sophisticated phishing attacks and zero-day vulnerabilities. As cyber threats continue to evolve, organizations must remain vigilant and proactive in their approach to information security.
