Horizon Alert
Summary of the vulnerability and why it matters
MDaemon Email Server is affected by a cross-site scripting vulnerability. This flaw allows an attacker to inject malicious JavaScript code into an email message. When a user views this email through the webmail interface, the JavaScript can execute within the user's browser session.
- MDaemon Email Server webmail
- Attacker injects JavaScript via email
- Arbitrary JavaScript executes in user's browser
Attack Path
How an attacker could exploit the issue
This vulnerability allows an attacker to execute arbitrary JavaScript code within a webmail user's browser session. The attack leverages a flaw in how HTML email messages are processed. By crafting a malicious email containing specific HTML and JavaScript, an attacker can trick a user into opening the email, leading to the execution of unauthorized code. This can result in various impacts, including session hijacking or the manipulation of the user's webmail interface.
- Exposure condition: Email service accessible externally.
- Attacker starting point: Remote attacker.
- Trigger and result: HTML email with JavaScript leads to arbitrary code execution.
Live Threat
Current exploitation, exposure, and threat context
A cross-site scripting vulnerability in MDaemon Email Server could allow attackers to inject malicious JavaScript into users' webmail sessions. This occurs when an attacker sends a specially crafted HTML email containing JavaScript within an image tag. Successful exploitation could lead to arbitrary JavaScript execution in the context of a webmail user's browser. The U.S. government has listed this as a known exploited vulnerability, indicating active threat actor interest and potential for urgent remediation.
- Attackers need moderate skill.
- Attackers require no privileges and network access.
- Business risk is high due to active exploitation.
Priority actions
Operational Fix
Recommended remediation, mitigation, and detection steps
This vulnerability allows attackers to execute arbitrary JavaScript code within a webmail user's browser by sending a specially crafted HTML email. Organizations using the affected software should prioritize identifying all instances of the product, then take steps to limit potential exposure. Finally, applying the vendor's provided fix and confirming its successful implementation is crucial, followed by ongoing monitoring.
- Find all instances of the affected product.
- Limit exposure or isolate risk.
- Fix, verify, and monitor.
