CompTIA Security+ SY0-701 Reddit Questions

Cryptojacking is the likely cause in this scenario. It involves malware that hijacks the resources of infected computers to mine cryptocurrency, usually without the user's knowledge. This type of attack doesn't typically degrade performance significantly or result in obvious system failures, which matches the situation described, where the machines showed no signs of degraded performance or excessive failed logins.

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CompTIA Security+ SY0-701 Course Content: Cryptojacking is covered under types of malware attacks, highlighting its stealthy nature and impact on infected systems​​.

Data exfiltration is a technique that attackers use to steal sensitive data from a target system or network by transmitting it through DNS queries and responses. This method is often used in advanced persistent threat (APT) attacks, in which attackers seek to persistently evade detection in the target environment. A large amount of unusual DNS queries to systems on the internet over short periods of time during non-business hours is a strong indicator of data exfiltration. A worm, a logic bomb, and ransomware would not use DNS queries to communicate with their command and control servers or perform their malicious actions. References: CompTIA Security+ Study Guide: Exam SY0-701, 9th Edition, page 487; Introduction to DNS Data Exfiltration; Identifying a DNS Exfiltration Attack That Wasn’t Real — This Time

IPSec is a protocol suite that provides secure communication over IP networks. IPSec can be used to create virtual private networks (VPNs) that encrypt and authenticate the data exchanged between two or more parties. IPSec can also provide data integrity, confidentiality, replay protection, and access control. A security consultant can use IPSec to gain secure, remote access to a client environment by establishing a VPN tunnel with the client’s network. References: CompTIA Security+ Study Guide: Exam SY0-701, 9th Edition, Chapter 8: Secure Protocols and Services, page 385 1