We introduce a novel SIP based attack, named as the SR-DRDoS attack, that exploits some less known SIP features by using the IP-spoofing technique, the reflection based attack logic and the DDoS attack logic. Furthermore, we develop a SIP-based DoS/DDoS attack simulator, named Mr. SIP, and use it to implement our SR-DRDoS attack. Our attack is shown to dramatically increase the CPU load of a SIP server from 0% up to 100% in only 4 minutes after the attack is initiated. Since our intelligent attack creates legitimate traffic on the SIP network by using reflection methods, it bypasses black-lists as well as IP, packet-count or session/transaction based rate limiting and automatic message generation detection systems which exist in state-of-the-art security perimeters such as firewalls, intrusion detection/prevention systems and anomaly detection systems. Moreover, we propose a novel defense mechanism that effectively mitigates our proposed DRDoS attack. Our defense mechanism is shown to successfully reduce the CPU load of a SIP server under attack from 71% down to 18% within 3 minutes after it is initiated.

We implement elliptic curve cryptography on the MSP430 which is a commonly used microcontroller in wireless sensor network nodes. We use the number theoretic transform to perform finite field multiplication and squaring as required in elliptic curve scalar point multiplication. We take advantage of the fast Fourier transform for the first time in the literature to speed up the number theoretic transform for an efficient realization of elliptic curve cryptography. Our implementation achieves elliptic curve scalar point multiplication in only $0.65$ s and $1.31$ s for multiplication of fixed and random points, respectively, and has similar or better timing performance compared to previous works in the literature.

Voice over Internet Protocol (VoIP) networks are vulnerable to caller-ID (caller-identification) spoofing attacks due to the open nature of Session Initiation Protocol (SIP) signaling. Caller-ID spoofing is a critical security threat in modern telecommunication systems, allowing attackers to impersonate legitimate callers and gain access to sensitive information. While these attacks pose a significant threat to the telecom and financial industries, the existing solutions are limited to only closed-circuit options for subscribers of the same service provider. In this paper, we present a novel blockchain-based solution to effectively prevent caller-ID spoofing attacks in real time. Our approach employs a low-latency consensus algorithm to manage and verify end-to-end the caller-ID information of Internet Service Providers (ISPs) and institutions. We propose a two-step verification process, in which the accuracy and integrity of Automatic Number Identification (ANI) information is verified at different stages of the call. The proposed solution initiates a renewal of the ISP registration on every caller-ID change, making it unaffected by unusual situations such as roaming, the use of an IP-PBX (Internet Protocol Private Branch Exchange), or the use of a VPN (Virtual Private Network). We also discuss the proposed solution’s feasibility and potential deployment issues, including its integration into existing RFC (Request for Comments) efforts and the necessary regulations for service providers to demonstrate compliance. Furthermore, we address future research directions, such as handling complex call scenarios such as call forwarding and teleconference calls. Our approach not only improves the security of telecommunication systems but also provides an efficient and scalable solution to prevent caller-ID spoofing attacks.

As wireless sensor networks (WSNs) become more widespread, potential attacks against them also increase and applying cryptography becomes inevitable to make secure WSN nodes. WSN nodes typically contain only a constrained microcontroller, such as MSP430, Atmega, etc., and running public key cryptography on these constrained devices is considered a challenge. Since WSN nodes are spread around in the field, the distribution of the shared private key, which is used in a symmetric key cryptographic algorithm for securing communications, is a problem. Thus, it is necessary to use public key cryptography to effectively solve the key distribution problem. The RSA cryptosystem, which requires at least a 1024-bit key, is the most widely used public key cryptographic algorithm. However, its large key size is considered a drawback for resource constrained microcontrollers. On the other hand, RSA allows for extremely fast digital signature generation which may make it desirable in applications where messages transmitted by sensor nodes need to be authenticated. Furthermore, for compatibility with an existing communication infrastructure, it may be desirable to adopt RSA in a WSN setting. With this work, we show that, in spite of its long key size, RSA is applicable for wireless sensor networks when optimized arithmetic, low-level coding and some acceleration algorithms are used. We pick three versions of the MSP430 microcontroller, which is used widely on wireless sensor network nodes, and implement 1024-bit RSA on them. Our implementation achieves 1024-bit RSA encryption and decryption operations on MSP430 in only $0.047$ s and $1.14$ s, respectively. In order to achieve these timings, we utilize several acceleration techniques, such as the subtractive Karatsuba-Ofman, Montgomery multiplication, operand scanning, Chinese remainder theorem and sliding window method. To the best of our knowledge, our timings for 1024-bit RSA encryption and decryption operations are the fastest reported timings in the literature for the MSP430 microcontroller.

Voice over Internet Protocol (VoIP) and its underlying Session Initiation Protocol (SIP) are widely deployed technologies since they provide an efficient and fast means of both voice and data communication over a single network. However, in spite of their advantages, they also have their security threats due to the inherent vulnerabilities in the underlying Internet Protocol (IP) that can potentially be exploited by hackers. This study introduces a novel defense mechanism to effectively combat advanced attacks that exploit vulnerabilities identified in some less-known features of SIP. The SIP-DRDoS (SIP-based distributed reflection denial of service) attack, which can survive the existing security systems, is an advanced attack that can be performed on an SIP network through the multiplication of legitimate traffic. In this study, we propose a novel defense mechanism that consists of statistics, inspection, and action modules to mitigate the SIP-DRDoS attack. We implement the SIP-DRDoS attack by utilizing our SIP-based audit and attack software in our VoIP/SIP security lab environment that simulates an enterprise-grade SIP network. We then utilize our SIP-based defense tool to realize our novel defense mechanism against the SIP-DRDoS attack. Our experimental results prove that our defense approach can do a deep packet analysis for SIP traffic, detect SIP flood attacks, and mitigate them by dropping attack packets. While the SIP-DRDoS attack with around 1 Gbps of traffic dramatically escalates the CPU (central processing unit) usage of the SIP server by up to $74\%$, our defense mechanism effectively reduces it down to $17\%$ within 6 min after the attack is initiated. Our approach represents a significant advancement over the existing defense mechanisms and demonstrates the potential to effectively protect VoIP systems against SIP-based DRDoS attacks.

We present a practical realization of Rivest-Shamir-Adleman (RSA) with a 2048-bit key on MSP430, a widely used microcontroller in wireless sensor network and Internet of things applications, and show that 2048-bit RSA is feasible on a constrained microcontroller. We exploit several methods for acceleration, e.g. Montgomery modular multiplication, subtractive Karatsuba-Ofman and Chinese remainder theorem (CRT) based modular exponentiation, and achieve RSA encryption and decryption with a 2048-bit key on MSP430 in just 0.14 s and 7.56 s, respectively. Our implementation on the low-end MSP430 microcontroller achieves 2048-bit RSA significantly faster (×2.9 and ×2.4 for encryption and decryption) with respect to the existing implementation in the literature on the comparable ATmega128 microcontroller. While our implementation is secure against the brute force attack due to its 2048-bit key, and thus 112-bit security level, it also includes the necessary side-channel countermeasures, e. g. message and key blinding, to help mitigate implementation attacks such as simple power analysis and differential power analysis.