CVE-2004-2719 in Foxmail
Summary
by MITRE
Buffer overflow in the UrlToLocal function in PunyLib.dll of Foxmail 5.0.300 allows remote attackers to execute arbitrary code via a mail message with a long From field, a different issue than CVE-2005-0339.
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Analysis
by VulDB Data Team • 07/05/2025
The vulnerability described in CVE-2004-2719 represents a critical buffer overflow flaw within the PunyLib.dll library component of Foxmail version 5.0.300. This issue specifically affects the UrlToLocal function which processes email headers, particularly the From field of incoming messages. The vulnerability stems from inadequate input validation and bounds checking within the email parsing routine, creating an exploitable condition where maliciously crafted email content can trigger memory corruption. The buffer overflow occurs when the UrlToLocal function processes a specially constructed From field that exceeds the allocated buffer size, allowing attackers to overwrite adjacent memory locations and potentially execute arbitrary code with the privileges of the affected application. This vulnerability is classified under CWE-121 as a stack-based buffer overflow, representing a fundamental flaw in memory management where the application fails to properly validate the length of input data before copying it into fixed-size buffers. The attack vector requires remote exploitation through email delivery, making it particularly dangerous for email clients that automatically process incoming messages without user intervention.
The operational impact of this vulnerability extends beyond simple code execution, as it provides attackers with a potential pathway for complete system compromise. When a user receives an email with a maliciously crafted From field, the Foxmail client automatically processes the header information during message parsing, triggering the buffer overflow condition. The exploitability of this vulnerability is enhanced by the fact that email clients typically process headers automatically, meaning users do not need to interact with malicious content to be affected. This makes the vulnerability particularly dangerous in enterprise environments where email is a primary communication channel and users may inadvertently receive malicious emails from compromised sources. The vulnerability's classification under ATT&CK technique T1190 indicates it represents a method for gaining initial access through email-based attacks, while also aligning with T1059 for remote code execution capabilities. The specific nature of the buffer overflow in PunyLib.dll suggests that the exploit may leverage return-oriented programming techniques or direct code injection to achieve arbitrary code execution, potentially bypassing modern security protections like DEP and ASLR through memory corruption techniques.
Mitigation strategies for CVE-2004-2719 should focus on immediate patching of the affected Foxmail version, as the vulnerability was addressed through updates to the PunyLib.dll component. Organizations should implement email filtering solutions that can identify and quarantine messages with suspicious header content, particularly those containing overly long From fields or unusual character sequences that may indicate buffer overflow attempts. Network-based intrusion detection systems should be configured to monitor for patterns associated with this vulnerability, including unusually long email headers or malformed content that could trigger the buffer overflow condition. Security administrators should also consider implementing email client sandboxing or virtualization techniques to isolate email processing from the core operating system, reducing the potential impact of successful exploitation. The vulnerability highlights the importance of proper input validation and bounds checking in email processing libraries, as recommended by industry standards such as the CERT/CC secure coding guidelines and OWASP secure coding practices. Additionally, regular security assessments of email client components should be conducted to identify similar buffer overflow vulnerabilities in other third-party libraries that may be susceptible to similar exploitation techniques. Organizations should also consider implementing email security gateways that can perform deep content inspection of incoming messages to prevent malicious headers from reaching end-user email clients. The remediation process should include not only patching the specific vulnerability but also reviewing and updating security policies to address the broader category of email-based buffer overflow attacks that could affect other components of the email infrastructure.