CVE-2007-4679 in Mac OS X
Summary
by MITRE
CFFTP in CFNetwork for Apple Mac OS X 10.4 through 10.4.10 allows remote FTP servers to force clients to connect to other hosts via crafted responses to FTP PASV commands.
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Analysis
by VulDB Data Team • 07/31/2019
The vulnerability described in CVE-2007-4679 represents a significant security flaw in the CFFTP component of Apple Mac OS X 10.4 through 10.4.10 operating systems. This issue resides within the CFNetwork framework's implementation of FTP client functionality, specifically affecting how the client processes Passive FTP (PASV) command responses from remote servers. The vulnerability stems from insufficient validation of FTP server responses, particularly those related to the PASV command which is used to establish data connections in FTP protocol communications. When a remote FTP server sends a crafted response to a PASV command, the vulnerable client will interpret this response and attempt to establish a data connection with the host specified in the manipulated response rather than the original server that issued the command.
This flaw creates a dangerous condition where an attacker controlling a malicious FTP server can redirect client connections to arbitrary hosts, potentially leading to man-in-the-middle attacks or unauthorized data access. The technical implementation issue occurs because the CFFTP client does not properly validate that the host specified in the PASV response matches the original server that issued the command. This validation gap allows attackers to inject malicious hostnames or IP addresses into the FTP connection process, effectively bypassing normal security boundaries that should prevent such redirection. The vulnerability operates at the network protocol level and affects the fundamental trust model of FTP client-server communications, where clients typically assume that responses from the originating server are legitimate and should be honored without additional verification.
The operational impact of this vulnerability extends beyond simple connection redirection, as it can enable sophisticated attack scenarios including credential theft, data interception, and unauthorized access to systems that rely on FTP for file transfers. Attackers can leverage this vulnerability to force clients to connect to malicious servers that may attempt to capture user credentials or intercept sensitive data transfers. The flaw affects all versions of Mac OS X 10.4 through 10.4.10, representing a broad attack surface that would have impacted numerous systems in enterprise and personal environments. This vulnerability aligns with CWE-20, which describes improper input validation, and can be categorized under ATT&CK technique T1071.004 for application layer protocol usage, specifically targeting FTP communications. The attack vector requires minimal privileges since it operates at the network protocol level and can be exploited through standard FTP server implementations without requiring special access rights.
The mitigation strategies for this vulnerability involve immediate system updates and patches provided by Apple to address the flawed FTP response handling logic. Users should upgrade to Mac OS X 10.4.11 or later versions where the vulnerability has been resolved through proper validation of PASV command responses. Additionally, network administrators should consider implementing firewall rules to restrict FTP traffic where possible, and organizations should conduct vulnerability assessments to identify systems running affected versions of the operating system. The fix typically involves implementing strict validation of hostnames in FTP responses, ensuring that any host specified in a PASV command must match the original server's identity or be explicitly validated through secure mechanisms. This vulnerability highlights the importance of secure implementation of network protocols and demonstrates how seemingly minor validation gaps can create significant security risks in client-server communications.