CVE-2015-5912 in iOS
Summary
by MITRE
The CFNetwork FTPProtocol component in Apple iOS before 9 allows remote FTP proxy servers to trigger TCP connection attempts to intranet hosts via crafted responses.
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Analysis
by VulDB Data Team • 11/21/2024
The vulnerability identified as CVE-2015-5912 resides within Apple iOS versions prior to 9.0, specifically affecting the CFNetwork FTPProtocol component. This flaw represents a significant security concern that enables remote attackers to manipulate network connections through maliciously crafted responses from FTP proxy servers. The issue stems from insufficient validation of FTP proxy responses, creating an avenue for attackers to influence the target system's network behavior.
The technical mechanism of this vulnerability involves the CFNetwork component's handling of FTP proxy server responses. When iOS devices connect to FTP servers through proxy configurations, the system processes responses from these intermediaries without adequate verification of the connection details provided. Attackers can exploit this by crafting malicious responses that contain deceptive host information, causing the iOS device to establish TCP connections to internal network hosts that would otherwise be inaccessible. This behavior occurs because the FTP protocol implementation fails to properly validate or sanitize the host information contained within proxy responses.
From an operational perspective, this vulnerability creates a serious risk for organizations relying on iOS devices for network connectivity. The attack vector allows remote FTP proxy servers to potentially access internal network resources that should remain protected from external access. This could enable attackers to perform reconnaissance activities, attempt unauthorized access to internal systems, or establish further attack vectors within the network infrastructure. The impact extends beyond simple information disclosure, as it can facilitate more complex attacks including internal network mapping and potential privilege escalation scenarios.
The vulnerability aligns with CWE-20, which describes improper input validation, and represents a classic case of insecure proxy handling within network protocols. From an ATT&CK framework perspective, this issue maps to techniques involving proxy server manipulation and network infiltration, specifically relating to T1071.004 for application layer protocol and T1011 for exfiltration. Organizations should implement immediate mitigations including updating iOS devices to version 9.0 or later, where Apple addressed this vulnerability through enhanced validation of FTP proxy responses and improved connection handling mechanisms. Additionally, network administrators should consider implementing stricter firewall rules and proxy server configurations to limit the exposure of internal systems to potentially malicious FTP proxy interactions.