Critical Roundcube Webmail Vulnerability (CVE-2023-43770) Exposes Users to Account Hijacking

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VTA-004475 – Critical Roundcube Webmail Vulnerability (CVE-2023-43770) Exposes Users to Account Hijacking

The Roundcube webmail software is currently under threat as attackers exploit the cross-site scripting (XSS) vulnerability CVE-2023-43770, despite a patch being issued in September 2023. CISA has included this vulnerability in its Known Exploited Vulnerabilities (KEV) catalog, warning of the risks posed by attackers. Roundcube, an open-source IMAP client, is susceptible to XSS attacks through crafted links in plain text email messages, potentially leading to information disclosure. This is not the first instance of Roundcube vulnerabilities being exploited, with previous cases reported in cyberespionage activities targeting Ukrainian state organizations and European governmental entities. CISA emphasizes the urgency of addressing such vulnerabilities, listing them in its KEV catalog as prioritized issues for federal agencies and providing a valuable resource for other organizations. Users of Roundcube are advised to remain vigilant for security updates and promptly implement patches, given the software’s active development and maintenance by its creators.


Attack Surfaces:

Command and Control, Execution, Exfiltration, Initial Access, Lateral Movement, Persistence, Privilege Escalation

T1531 – Account Access Removal
T1566 – Phishing
T1059 – Command and Scripting Interpreter
T1059.001 – PowerShell
T1059.007 – JavaScript
T1203 – Exploitation for Client Execution
T1068 – Exploitation for Privilege Escalation


SuperPRO’s Threat Countermeasures Procedures: 
1. Update Roundcube webmail to the latest version.
2. Regularly check for updates and apply them promptly.
3. Conduct a thorough vulnerability assessment of the organization’s webmail system.
4. Enforce the use of multi-factor authentication (MFA) for all Roundcube webmail accounts.
5. Conduct cybersecurity training sessions for employees to educate them about the importance of avoiding suspicious email links and recognizing potential phishing attempts.
6. Strengthen monitoring and logging mechanisms to detect any unusual or suspicious activities related to Roundcube webmail.

Contributed by: Kai Sheng