CVE-2021-38372 in Trojita
Summary
by MITRE • 08/10/2021
In KDE Trojita 0.7, man-in-the-middle attackers can create new folders because untagged responses from an IMAP server are accepted before STARTTLS.
Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.
Analysis
by VulDB Data Team • 08/15/2021
The vulnerability CVE-2021-38372 affects KDE Trojita version 0.7, a popular email client that implements the IMAP protocol for email retrieval. This issue represents a critical security flaw in the client's handling of secure communication channels, specifically during the initial connection establishment phase. The vulnerability stems from improper protocol handling that allows malicious actors to manipulate the connection process before encryption is properly established.
The technical flaw occurs when the IMAP client connects to a mail server and processes untagged responses from the server before the STARTTLS command has been successfully negotiated and executed. In standard IMAP security protocols, clients should wait for the server to acknowledge the STARTTLS command and complete the TLS encryption handshake before accepting any untagged responses that might contain commands or data. However, KDE Trojita 0.7 fails to enforce this critical sequence, allowing attackers to inject malicious responses during this window.
This vulnerability falls under the CWE-310 weakness category, specifically related to cryptographic issues and improper handling of security protocols. The man-in-the-middle attack scenario enables adversaries to intercept and manipulate the communication between the email client and the mail server. Attackers can create new folders, modify existing folder structures, or potentially gain unauthorized access to email data by exploiting this timing gap in the protocol implementation.
The operational impact of this vulnerability is significant for users who rely on KDE Trojita for email management, particularly in environments where network security cannot be guaranteed. The attack can be executed against any IMAP server that does not properly validate the connection state before processing untagged responses. This creates a persistent security risk where attackers can manipulate folder structures without the user's knowledge, potentially leading to data loss, unauthorized access to sensitive information, or complete compromise of the email account.
Security mitigations for this vulnerability involve immediate software updates to the latest version of KDE Trojita where the protocol handling has been corrected to properly enforce the STARTTLS sequence before accepting untagged responses. Organizations should also implement network monitoring to detect unusual folder creation patterns and ensure that all email clients are configured to require secure connections by default. The fix aligns with ATT&CK technique T1071.004, which covers application layer protocol: email protocols, and addresses the broader category of credential access through network protocol manipulation. Additionally, users should verify that their email servers are configured to require STARTTLS for all connections and that certificate validation is properly enforced to prevent downgrade attacks that could exploit this vulnerability.