CVE-2014-7284 in Linux
Summary
by MITRE
The net_get_random_once implementation in net/core/utils.c in the Linux kernel 3.13.x and 3.14.x before 3.14.5 on certain Intel processors does not perform the intended slow-path operation to initialize random seeds, which makes it easier for remote attackers to spoof or disrupt IP communication by leveraging the predictability of TCP sequence numbers, TCP and UDP port numbers, and IP ID values.
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Analysis
by VulDB Data Team • 02/21/2022
The vulnerability described in CVE-2014-7284 represents a critical weakness in the Linux kernel's random number generation mechanism specifically affecting versions 3.13.x and 3.14.x before 3.14.5 on Intel processors. This flaw resides in the net_get_random_once function within net/core/utils.c, which is responsible for initializing random seeds used in various network protocols. The issue stems from improper handling of the slow-path operation that should occur during random seed initialization, creating predictable patterns in cryptographic randomness that underpins network security. The vulnerability is particularly concerning because it affects fundamental network operations that rely on unpredictable values to maintain security properties. When the slow-path operation fails to execute properly, the random number generator produces sequences that exhibit statistical predictability, directly compromising the security assumptions that network protocols depend upon.
The technical implementation flaw manifests when certain Intel processors fail to properly execute the random seed initialization sequence that would normally occur through the slow-path execution path. This failure results in the generation of predictable values for TCP sequence numbers, UDP port numbers, and IP ID values that are crucial for network communication security. The predictability arises because the random number generator does not properly mix entropy sources, leaving patterns that can be exploited by attackers. According to CWE-330, this represents a weakness in entropy sources where insufficient randomness leads to predictable outputs. The vulnerability specifically impacts the kernel's ability to generate secure random numbers for network protocol operations, which directly violates the fundamental security requirements for cryptographic randomness in network communications.
The operational impact of CVE-2014-7284 extends beyond simple predictability issues to enable sophisticated network attacks that can compromise communication integrity and availability. Remote attackers can exploit this vulnerability to perform sequence number prediction attacks against TCP connections, potentially allowing them to inject malicious data into established sessions or perform session hijacking attacks. The vulnerability also affects UDP and IP protocols by making port number and IP ID value prediction possible, enabling attackers to spoof network packets more effectively. This weakness creates opportunities for man-in-the-middle attacks, connection disruption, and denial-of-service scenarios where attackers can manipulate network flow without detection. The ATT&CK framework categorizes this under T1071.004 for application layer protocol manipulation, where predictable network values enable protocol-level attacks. The vulnerability's impact is particularly severe because it affects the core network stack functionality that all network applications depend upon, making it a critical security concern for any system running affected kernel versions.
Mitigation strategies for CVE-2014-7284 focus on applying the official kernel patch released by the Linux kernel development team, which addresses the specific implementation flaw in the net_get_random_once function. Organizations should immediately upgrade to kernel versions 3.14.5 or later where the vulnerability has been corrected. The patch ensures proper execution of the slow-path operation for random seed initialization, restoring the intended cryptographic randomness properties. System administrators should also implement network monitoring to detect unusual patterns in TCP sequence numbers, IP IDs, and port usage that might indicate exploitation attempts. Additional mitigations include implementing network segmentation, using intrusion detection systems, and applying firewall rules to limit exposure. The vulnerability demonstrates the importance of proper entropy handling in kernel security and highlights the need for comprehensive testing of cryptographic implementations on specific processor architectures. Organizations should also consider implementing network protocol security measures such as TCP SYN cookies and other anti-automation techniques to reduce the attack surface when running older kernel versions that cannot be immediately patched.