Last year, brute-forcing passwords and exploiting ProxyLogon vulnerabilities against Microsoft Exchange Server were among the most prominent attack methods. According to ESET's Q3 Threat Report, which covers September to December 2021, while supply chain attacks increased over 2020, the year 2021 was marked by the continuous discovery of zero-day vulnerabilities potent enough to wreak havoc on enterprise systems. The discovery of zero-day flaws in Exchange Server, as well as Microsoft's emergency patches to address on-premise issues, haunted IT admins well into the year.
The end of the year was similarly tumultuous in terms of RDP attacks, which grew in severity throughout 2020 and 2021. Despite the fact that 2021 was no longer distinguished by the chaos of freshly imposed lockdowns and fast migrations to remote work, the data from the final weeks of T3 2021 eclipsed all prior records, amounting to a remarkable yearly surge of 897% in total attack attempts thwarted. The only positive news from the RDP attack front is that the number of targets has been gradually decreasing, albeit the rampage does not appear to be coming to a stop anytime soon.
Ransomware, previously described as "more aggressive than ever" in the Q4 2020 Threat Report, outperformed the worst predictions in 2021, with attacks on critical infrastructure, outrageous ransom demands, and over US$5 billion in bitcoin transactions tied to potential ransomware payments identified in the first half of 2021 alone.
However, the pressure from the opposing side has been increasing as well, as evidenced by increased law enforcement efforts against ransomware and other cybercriminal endeavors. While the intensive crackdown prompted numerous gangs to quit the scene – even providing decryption keys – it appears that other attackers are becoming even more daring: T3 saw the biggest ransom demand yet, US$240 million, tripling the prior report's figure.
The repercussions of a critical vulnerability in Log4j were also discovered in the last four months of 2021. The remote code execution (RCE) flaw in Log4j, tracked as CVE-2021-44228, received a CVSS severity level of 10.0, sending organizations scrambling to repair the problem. Threat actors immediately began attempting to exploit the flaw.
Despite the fact that the vulnerability was only made public in the last three weeks of 2021, ESET has classified CVE-2021-44228 as one of the top five attack vectors of the year.
According to the study, there has been a significant increase in Android banking malware, with a 428% increase in 2021 compared to 2020. According to ESET, infection rates connected with Android banking Trojans including SharkBot, Anatsa, Vultur, and BRATA have now surpassed adware levels.
