Heuristic Recon of IPv6 Addresses Based on Their Characteristics

Previously, we mentioned that IPv6 addresses, when assigned, can, for example, include random values in particular bytes or embed MAC addresses. With these facts in mind, we exercised some restrictions to narrow down the address space to be scanned.

Specifically, we employed the following approaches to conduct the recon based on data from the collection of IPv6 addresses available on Hitlist.

• Recon of low-byte addresses and addresses containing random bits in particular bytes

For low-byte IPv6 addresses, the recon method is similar to that for IPv4 addresses. Such addresses contain 0s in all bytes except the least significant byte, so it is only necessary to base the scan on this part (least significant byte).

For those containing random bits in particular bytes than in the least significant byte, Scan6 uses hexadecimal notation to specify the scanning scope so as to traverse only specified bits. To do so, we ran the “scan6 -i eth0 -d ****:983:0-3000::1” command, in which 0-3000 (hexadecimal) specifies
the traversal scope. It took about 1 minute to complete a scan of 12,288 IPv6 addresses, with 3853 active ones found, as shown in Figure 2-13.

Identification of IoT Assets from Known IPv6 Addresses

The preceding section gives a brief account of difficulties in the blind-scan of IPv6 addresses. To work around these problems, we based our recon on some available IPv6 addresses, in a bid to discover IoT assets operating in IPv6 environments. Sources of these addresses include Hitlist27, which maintains about 3 million IPv6 addresses, and NSFOCUS Threat Intelligence (NTI), which provides a collection of about 1.7 billion IPv6 addresses extracted from domain name intelligence. Note that the IPv6 addresses available for our recon are but a very small portion of the total number. Besides, IoT assets found active in IPv6 environments were rather small in number.

This section presents the exposure of IPv6 assets on the Internet and methods for recon of these assets. IPv6 Evolution With the IoT and 5G gaining ground, the demand of network applications for IP addresses is undergoing an explosive growth. However, the IPv4 address space has been depleted and IPv4 addresses have been unevenly allocated. […]

Overview

2020 H1 witnessed nine Internet of Things (IoT) security events that deserved close attention:

• Ripple20 0-day vulnerabilities were discovered and affected hundreds of millions of networked devices in various industries across the globe.
• A high-risk 0-day vulnerability was detected in dozens of Netgear router products.
• A group of Industrial Control System (ICS) honeypots attracted four 0-day attacks.
• A critical remote code execution (RCE) vulnerability affected millions of network devices based on OpenWrt.
• Hackers exploited 0-day vulnerabilities in DrayTek devices to launch attacks on enterprise networks.
• Hackers hijacked a smart building access system and could launch distributed denial-of-service (DDoS) attacks on devices accessible via networks.
• Millions of devices using LoRaWAN were vulnerable to hacker attacks, and nodes, gateways, and servers in the LoRaWAN network were prone to critical vulnerabilities. Therefore, their security protection capabilities remained to be improved.
• Hackers divulged Telnet credentials of over 500,000 devices.
• Researchers discovered LiquorBot, which was a new botnet with the cryptomining function.

Introduction

As we indicated in the 2018 Annual IoT Security Report, network addresses on the Internet constantly change. Use of historical data to delineate exposure of assets will result in a deviation from reality, presenting a value higher than the actual number. Therefore, to accurately reflect the reality of a given area, we should specify a short period as the statistical cycle when calculating the number. This chapter starts with an analysis of the actual exposure of IoT assets in 2019.

With the booming of IoT applications and depletion of IPv4 addresses, IPv6 addresses will be gradually adopted, which is an irreversible trend. This means that IoT assets on IPv6 networks will become major targets of attackers. In this sense, it will be of great significance to cybersecurity to accurately survey IPv6 assets and services. For this reason, we also describe the methods for discovering IoT assets in IPv6 environments and analyze their exposure in this chapter.