CVE-2007-5769 in ftp
Summary
by MITRE
Double free vulnerability in the getreply function in ftp.c in netkit ftp (netkit-ftp) 0.17 20040614 and later allows remote FTP servers to cause a denial of service (application crash) and possibly have unspecified other impact via some types of FTP protocol behavior. NOTE: the netkit-ftpd issue is covered by CVE-2007-6263.
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Analysis
by VulDB Data Team • 09/12/2018
The CVE-2007-5769 vulnerability represents a critical double free memory error in the netkit-ftp implementation that affects versions 0.17 20040614 and later. This flaw exists within the getreply function of the ftp.c file, which is responsible for processing responses from FTP servers during client operations. The vulnerability manifests when remote FTP servers send malformed or unexpected protocol responses that trigger improper memory management handling within the client application. The double free condition occurs when the same memory block is freed twice during the processing of specific FTP protocol interactions, creating a potential for arbitrary code execution or complete application termination.
From a technical perspective, this vulnerability falls under CWE-415, which specifically addresses double free conditions in memory management operations. The flaw exploits the lack of proper input validation and error handling within the FTP client's response parsing mechanism. When the getreply function encounters certain malformed FTP responses, it fails to properly validate the state of memory pointers before attempting to free allocated resources. This creates a scenario where a memory block that has already been released is targeted for a second free operation, leading to undefined behavior that can be exploited by remote attackers. The vulnerability is particularly dangerous because it can be triggered through normal FTP protocol operations without requiring authentication or special privileges.
The operational impact of this vulnerability extends beyond simple denial of service scenarios, as demonstrated by the potential for unspecified other impacts mentioned in the original description. Remote FTP servers can leverage this double free condition to cause application crashes that may result in service unavailability for legitimate users. In more severe cases, the memory corruption resulting from the double free could potentially be exploited to execute arbitrary code on the affected system, particularly when the vulnerable client application runs with elevated privileges. This makes the vulnerability particularly concerning for systems that frequently interact with untrusted FTP servers or that serve as FTP clients for automated processes.
Mitigation strategies for CVE-2007-5769 should prioritize immediate patching of affected netkit-ftp installations to versions that contain memory management fixes for the getreply function. System administrators should implement network segmentation to limit exposure to untrusted FTP servers and consider deploying network filtering rules that restrict FTP traffic from potentially malicious sources. The vulnerability aligns with ATT&CK technique T1210, which covers exploitation of remote services through memory corruption vulnerabilities, making it essential for security teams to monitor for potential exploitation attempts. Additionally, organizations should consider implementing application whitelisting controls and ensuring that FTP client applications are running with minimal required privileges to limit potential damage from successful exploitation attempts.