CVE-2013-4698 in Mailwise
Summary
by MITRE
Cybozu Mailwise 5.0.4 and 5.0.5 allows remote authenticated users to obtain sensitive e-mail content intended for different persons in opportunistic circumstances by reading Subject header lines within the user s own mailbox.
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Analysis
by VulDB Data Team • 03/01/2019
The vulnerability identified as CVE-2013-4698 affects Cybozu Mailwise versions 5.0.4 and 5.0.5, representing a significant information disclosure flaw that undermines the confidentiality of email communications. This vulnerability falls under the category of improper access control and can be classified as CWE-284, which addresses inadequate access control mechanisms. The flaw specifically exploits a weakness in how the mail system handles subject line visibility, creating an opportunity for authenticated attackers to access emails intended for other users through the subject headers present in their own mailbox.
The technical implementation of this vulnerability stems from insufficient validation of email access permissions within the Mailwise application. When authenticated users access their email mailbox, the system fails to properly isolate email metadata, particularly subject lines, from messages addressed to other recipients. This occurs during opportunistic circumstances where an attacker can leverage their legitimate access to read subject headers of emails that were not intended for their personal mailbox. The vulnerability is particularly concerning because it operates without requiring additional privileges or compromising the authentication mechanism itself.
Operational impact of this vulnerability extends beyond simple information disclosure, as it can enable attackers to gather intelligence about communication patterns, identify potential targets, and understand the organizational structure through email subject lines. The attack vector requires only authenticated access to the system, making it relatively accessible to malicious insiders or compromised accounts. This weakness can be exploited to conduct reconnaissance activities, identify sensitive topics within the organization, and potentially uncover confidential information that might not be directly accessible through other means. The vulnerability demonstrates a fundamental flaw in the application's security model regarding data isolation and access control enforcement.
The exploitation of this vulnerability aligns with ATT&CK technique T1213.002, which involves accessing data from cloud storage services, and can be categorized under the broader ATT&CK tactic of Credential Access. Organizations using affected versions of Cybozu Mailwise should implement immediate mitigations including updating to patched versions of the software, implementing additional access controls, and conducting security reviews of email handling procedures. System administrators should also consider implementing network monitoring to detect unusual access patterns that might indicate exploitation attempts. The vulnerability underscores the importance of proper access control implementation and data isolation mechanisms in email systems, particularly when dealing with multi-user environments where sensitive communications are handled.