CVE-2009-0569 in Becky! Internet Mail
Summary
by MITRE
Buffer overflow in Becky! Internet Mail 2.48.02 and earlier allows remote attackers to execute arbitrary code via a mail message with a crafted return receipt request.
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Analysis
by VulDB Data Team • 12/07/2017
The vulnerability described in CVE-2009-0569 represents a critical buffer overflow flaw affecting Becky! Internet Mail version 2.48.02 and earlier. This security issue resides within the email client's handling of return receipt requests, which are automated notifications sent by email clients when a recipient opens or acknowledges receipt of a message. The flaw occurs when the application processes a specially crafted return receipt request embedded within an email message, leading to memory corruption that can be exploited by malicious actors.
This buffer overflow vulnerability stems from inadequate input validation and memory management within the Becky! email client's parsing mechanism. When the application encounters a malformed return receipt request containing excessive data, it fails to properly bounds-check the input before copying it into a fixed-size buffer. The lack of proper boundary checking allows attackers to overwrite adjacent memory locations, potentially corrupting the program's execution flow and enabling arbitrary code execution. The vulnerability specifically affects the client-side processing of email headers and return receipt parameters, making it particularly dangerous in environments where users regularly receive email from untrusted sources.
The operational impact of this vulnerability extends beyond simple code execution, as it can enable attackers to gain complete control over affected systems running vulnerable versions of Becky! Internet Mail. An attacker could craft a malicious email message containing a specially constructed return receipt request that, when processed by the vulnerable client, would allow remote code execution with the privileges of the user running the email client. This creates a significant risk for enterprise environments where users may inadvertently open malicious emails, potentially leading to full system compromise, data exfiltration, or lateral movement within network infrastructure. The vulnerability's remote exploitability means that attackers do not require local access to the target system, making it particularly concerning for email-based attack campaigns.
The technical nature of this vulnerability aligns with CWE-121, which describes heap-based buffer overflow conditions, and can be categorized under the ATT&CK technique T1203 - Exploitation for Client Execution. Organizations should immediately implement mitigations including updating to Becky! Internet Mail version 2.48.03 or later, which contains the necessary patches to address the buffer overflow. Network administrators should also consider implementing email filtering solutions that can detect and block suspicious return receipt requests, while users should be educated about the risks of opening emails from unknown senders. Additionally, system hardening measures such as disabling automatic return receipt generation and implementing strict email content filtering policies can help reduce the attack surface. The vulnerability demonstrates the importance of proper input validation and memory management in client-side applications, particularly those handling untrusted data from network sources, and serves as a reminder of the critical need for regular security updates and patch management programs.