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Technical Support Scams (TSS), which combine online abuse with social engineering over the phone channel, have persisted despite several law enforcement actions. Although recent research has provided important insights into TSS, these scams have now evolved to exploit ubiquitously used online services such as search and sponsored advertisements served in response to search queries. We use a data-driven approach to understand search-and-ad abuse by TSS to gain visibility into the online infrastructure that facilitates it. By carefully formulating tech support queries with multiple search engines, we collect data about both the support infrastructure and the websites to which TSS victims are directed when they search online for tech support resources. We augment this with a DNSbased amplification technique to further enhance visibility into this abuse infrastructure. By analyzing the collected data, we provide new insights into search-and-ad abuse by TSS and reinforce some of the findings of earlier research. Further, we demonstrate that tech support scammers are (1) successful in getting major as well as custom search engines to return links to websites controlled by them, and (2) they are able to get ad networks to serve malicious advertisements that lead to scam pages. Our study period of approximately eight months uncovered over 9,000 TSS domains, of both passive and aggressive types, with minimal overlap between sets that are reached via organic search results and sponsored ads. Also, we found over 2,400 support domains which aid the TSS domains in manipulating organic search results. Moreover, to our surprise, we found very little overlap with domains that are reached via abuse of domain parking and URL-shortening services which was investigated previously. Thus, investigation of search-and-ad abuse provides new insights into TSS tactics and helps detect previously unknown abuse infrastructure that facilitates these scams.

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Masking of gates is one of the most popular techniques to prevent differential power analysis (DPA) of AES algorithm. It has been shown that the logic circuits used in the implementation of cryptographic algorithms leak side-channel information inspite of masking, which can be exploited, in differential power attacks. The phenomenon in CMOS circuits responsible for the leakage of masked circuits is known as glitching. Motivated by this fact, the authors analyse the effect of glitches in CMOS circuits against masked implementation of the AES S-box. The authors explicitly demonstrate that glitches do not affect always. There exists a relation between combinational path delay of the circuit and timing difference of input vectors to the circuit, which has a bearance on the amount of information leaked by the masked gates. A balanced masked S-box circuit is proposed where the inputs are synchronised by sequential components. Detailed SPICE results are shown to support the claim that the modifications indeed reduce the vulnerability of the masked AES S-box against DPA attacks.