CVE-2021-38542 in James
Summary
by MITRE • 01/04/2022
Apache James prior to release 3.6.1 is vulnerable to a buffering attack relying on the use of the STARTTLS command. This can result in Man-in -the-middle command injection attacks, leading potentially to leakage of sensible information.
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Analysis
by VulDB Data Team • 01/06/2022
Apache James versions prior to 3.6.1 contain a critical buffering vulnerability that exploits the STARTTLS command implementation, creating a pathway for man-in-the-middle command injection attacks. This vulnerability stems from inadequate input validation and buffer handling within the email server's secure communication protocol implementation. The flaw allows attackers to manipulate the TLS negotiation process through crafted STARTTLS commands, potentially intercepting or injecting commands during the secure connection establishment phase.
The technical exploitation occurs when the vulnerable James server processes STARTTLS commands without proper boundary checking or input sanitization. Attackers can craft malicious input sequences that overflow buffers or manipulate command parsing logic, enabling them to inject arbitrary commands into the server's processing pipeline. This buffer-related vulnerability specifically targets the protocol handling mechanisms that manage secure email transmission, making it particularly dangerous for email infrastructure. The issue falls under CWE-121, heap-based buffer overflow, and CWE-78, OS command injection, representing a dual threat that combines memory corruption with command execution capabilities.
The operational impact of this vulnerability extends beyond simple information leakage to encompass complete system compromise potential. An attacker who successfully exploits this vulnerability could gain unauthorized access to email communications, potentially reading sensitive messages, modifying email content, or even establishing persistent access to the email server. The man-in-the-middle attack vector allows for passive monitoring of email traffic during TLS negotiation, while the command injection aspect enables active exploitation of the server's functionality. This vulnerability directly maps to ATT&CK technique T1071.004 for application layer protocol and T1566 for phishing, as it enables both passive surveillance and active command execution against email infrastructure.
Organizations running vulnerable Apache James versions face significant security risks including unauthorized data access, email spoofing, and potential lateral movement within network environments. The vulnerability's impact is amplified in environments where James servers handle sensitive corporate or personal communications, as the compromise could lead to intellectual property theft, identity theft, or regulatory compliance violations. The buffer overflow characteristics mean that exploitation could potentially crash the email service or allow for more sophisticated attack vectors including privilege escalation.
Mitigation strategies should prioritize immediate patching to Apache James 3.6.1 or later versions where the buffer handling has been corrected. Network segmentation and firewall rules should be implemented to restrict access to email services, particularly during TLS negotiation phases. Additional monitoring should be deployed to detect anomalous STARTTLS command sequences or unusual protocol behavior that might indicate exploitation attempts. Organizations should also implement proper input validation controls and consider deploying intrusion detection systems specifically configured to identify buffer overflow patterns and command injection attempts. The fix addresses the root cause by implementing proper buffer boundary checking and input sanitization within the STARTTLS command processing logic, preventing the exploitation vectors that led to the vulnerability.