CVE-2015-2914 in Almond
Summary
by MITRE
Securifi Almond devices with firmware before AL1-R201EXP10-L304-W34 and Almond-2015 devices with firmware before AL2-R088M use a fixed source-port number in outbound DNS queries performed on behalf of any device, which makes it easier for remote attackers to spoof responses by using this number for the destination port, a different vulnerability than CVE-2015-7296.
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Analysis
by VulDB Data Team • 11/07/2024
The Securifi Almond devices represent a class of IoT gateway appliances that facilitate communication between home networks and external services through various protocols including DNS resolution. These devices operate as intermediaries between local IoT devices and cloud services, requiring outbound network connectivity for their operational functionality. The vulnerability in question specifically affects the DNS query implementation within these appliances, creating a predictable network behavior that undermines security assumptions. The affected firmware versions indicate a widespread issue across multiple device generations, suggesting a fundamental flaw in the network stack implementation rather than an isolated incident. This vulnerability impacts both the AL1 and AL2 device families, demonstrating the scope of the underlying implementation issue.
The technical flaw manifests in the use of a fixed source port number for outbound DNS queries, a practice that violates fundamental security principles for network communications. When devices make DNS requests, they typically use ephemeral port numbers to establish unique communication channels that make spoofing attacks significantly more difficult. However, the fixed source port approach creates a predictable pattern that adversaries can exploit. The vulnerability specifically references a destination port spoofing attack vector where attackers can use the known fixed source port to craft malicious DNS responses that appear legitimate to the appliance. This represents a classic case of insufficient randomness in network protocol implementation, where the predictable nature of port selection creates a vulnerability that can be exploited without requiring extensive reconnaissance or privilege escalation.
The operational impact of this vulnerability extends beyond simple DNS spoofing, as it compromises the integrity of network communications within the home network ecosystem. Attackers who can observe network traffic or have access to the local network segment can potentially redirect DNS responses to malicious servers, enabling various attack vectors including man-in-the-middle scenarios, phishing attacks, and service disruption. The vulnerability is particularly concerning for IoT environments where devices may be configured to trust DNS responses from the gateway without additional validation mechanisms. The fact that this vulnerability exists alongside CVE-2015-7296 suggests a pattern of network protocol implementation weaknesses in the Securifi appliance line, indicating potential systemic issues in how these devices handle outbound network communications. This flaw effectively undermines the trust model that IoT gateways are expected to provide, making it easier for attackers to compromise the entire network ecosystem.
Mitigation strategies for this vulnerability should focus on both immediate firmware updates and network-level protective measures. Device manufacturers should implement proper port selection algorithms that utilize random or pseudo-random port numbers for outbound DNS queries, aligning with established security practices for network protocol implementation. The fix should ensure that source port selection follows cryptographic best practices to prevent predictability while maintaining operational functionality. Network administrators should consider implementing DNS filtering and monitoring solutions to detect anomalous DNS traffic patterns that might indicate exploitation attempts. Additionally, network segmentation and firewall rules can help limit the impact of successful attacks by restricting communication paths between the gateway and other network segments. This vulnerability aligns with CWE-338, which addresses the use of cryptographically weak pseudo-random number generators, and represents a clear violation of the principle of least privilege in network communications. The ATT&CK framework would categorize this as a network infiltration technique leveraging predictable communication patterns, potentially enabling further attacks through DNS-based reconnaissance and command and control channel establishment.