CVE-2008-3612 in iPod touch
Summary
by MITRE
The Networking subsystem in Apple iPod touch 2.0 through 2.0.2, and iPhone 2.0 through 2.0.2, uses predictable TCP initial sequence numbers, which allows remote attackers to spoof or hijack a TCP connection.
Be aware that VulDB is the high quality source for vulnerability data.
Analysis
by VulDB Data Team • 09/03/2019
The vulnerability described in CVE-2008-3612 represents a critical weakness in the networking stack of early Apple mobile devices, specifically affecting iPod touch and iPhone models running firmware versions 2.0 through 2.0.2. This issue stems from the predictable nature of TCP initial sequence numbers generated by the device's networking subsystem, creating a significant security risk that can be exploited by remote attackers. The vulnerability directly impacts the fundamental security mechanisms of TCP communication protocols, which rely on unpredictable sequence numbers to prevent connection hijacking attacks.
The technical flaw in this vulnerability manifests through the use of predictable TCP initial sequence numbers, which violates the core security principle that sequence numbers must be cryptographically random to prevent spoofing attacks. When a TCP connection is established, each side generates an initial sequence number that serves as the foundation for the entire connection's sequence space. In affected Apple devices, the random number generator used to create these initial sequence numbers was found to be insufficiently random, allowing attackers to predict future sequence numbers based on observed patterns. This weakness falls under the CWE-330 category of "Use of Insufficiently Random Values" and represents a direct violation of the cryptographic requirements outlined in NIST SP 800-90 for random number generation.
The operational impact of this vulnerability is substantial, as it enables remote attackers to perform TCP connection hijacking attacks against Apple devices without requiring physical access or complex local privileges. An attacker can exploit this weakness by monitoring network traffic to capture initial sequence numbers, then use these predictable values to inject malicious data into established connections or establish entirely new connections that appear legitimate to the target device. This capability allows for man-in-the-middle attacks, session hijacking, and potential data interception or modification. The attack vector is particularly concerning given that these devices were commonly used for sensitive communications and data transfer, making the exploitation of this vulnerability a significant threat to user privacy and data integrity.
From a defensive standpoint, this vulnerability highlights the importance of proper random number generation in network security implementations and demonstrates how seemingly minor implementation flaws can have major security consequences. The recommended mitigations include immediate firmware updates from Apple to address the predictable sequence number generation issue, implementation of additional network monitoring to detect suspicious connection patterns, and consideration of network-level protections such as TCP sequence number randomization at the network boundary. Organizations should also implement proper network segmentation and access controls to limit the potential impact of such attacks. This vulnerability aligns with the ATT&CK technique T1071.004 for application layer protocol traffic shaping and represents a classic example of how weak cryptographic primitives can undermine network security. The incident underscores the necessity for comprehensive security testing of networking components, particularly in mobile environments where devices frequently establish connections with untrusted networks, and emphasizes the critical need for robust entropy sources in security-sensitive applications.