CVE-2015-7296 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 linear algorithm for selecting the ID value in the header of a DNS query performed on behalf of the device itself, which makes it easier for remote attackers to spoof responses by including this ID value, as demonstrated by a response containing the address of the firmware update server, a different vulnerability than CVE-2015-2914.
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Analysis
by VulDB Data Team • 11/10/2024
The Securifi Almond devices represent a class of IoT gateway appliances that connect home networks to cloud services, making them critical entry points for smart home ecosystems. These devices operate by performing DNS queries on behalf of connected IoT devices to resolve cloud service addresses and facilitate communication. The vulnerability in question stems from the predictable nature of ID value selection within DNS query headers, a flaw that directly impacts the security of the device's communication channels. This vulnerability affects specific firmware versions including AL1-R201EXP10-L304-W34 and AL2-R088M, indicating a widespread issue across multiple device generations within the Securifi product line.
The technical flaw manifests in the use of a linear algorithm for generating DNS query IDs, which are meant to provide uniqueness and prevent response spoofing in DNS communications. When a device sends a DNS query, it includes a unique identifier in the query header that should be random and unpredictable to ensure that responses can be correctly matched to their corresponding queries. However, the linear algorithm approach means that attackers can predict or enumerate these ID values through observation and analysis of the device's query patterns. This predictability creates a window of opportunity for man-in-the-middle attacks where malicious actors can intercept DNS responses and inject falsified data using the known ID values, effectively bypassing the intended security mechanisms that protect against such attacks.
The operational impact of this vulnerability extends beyond simple DNS spoofing, as it specifically enables attackers to manipulate firmware update processes. The demonstration shows how an attacker could craft a response containing the address of a firmware update server, potentially leading to unauthorized firmware installation or redirection to malicious servers. This creates a significant risk for device compromise, as firmware updates are critical for maintaining security patches and device functionality. The vulnerability's relationship to CVE-2015-2914 demonstrates a pattern of DNS-related weaknesses in IoT device implementations, where the predictability of network communication elements undermines fundamental security assumptions. This issue aligns with CWE-330, which addresses the use of insufficiently random values in security contexts, and represents a clear violation of the principle that security-critical identifiers should be generated using cryptographically secure random number generators.
Mitigation strategies for this vulnerability require both immediate and long-term approaches to address the fundamental design flaw in the device's DNS query implementation. Device manufacturers should implement proper random number generation for DNS query IDs, ensuring that these values cannot be predicted or enumerated by attackers. Network administrators should monitor for suspicious DNS traffic patterns and implement DNS sinkhole configurations to redirect traffic away from known malicious servers. The vulnerability highlights the importance of following security standards such as those outlined in the NIST SP 800-90A for random number generation and demonstrates how ATT&CK technique T1071.004 (DNS Tunneling) can be leveraged when DNS security mechanisms are weakened. Organizations should also consider implementing network segmentation and monitoring solutions that can detect anomalous DNS query patterns, particularly those involving firmware update servers, to prevent exploitation of this vulnerability in production environments.