Cisco Updated 200-201 Exam Questions and Answers by wilf

 The regex [a−z]+ matches one or more lowercase letters from a to z. The plus sign (+) indicates that the preceding character set [a−z] can appear one or more times, thus matching strings of only lowercase letters1.

References := This explanation is consistent with standard regex syntax as described in various programming and scripting languages documentation

The Cuckoo report indicates that the file has been identified by Yara rules as being capable of detecting a sandbox environment, which is a security mechanism for isolating and analyzing suspicious code. The presence of the “vmdetect” and “anti_dog” Yara rules suggests that the file may have mechanisms to avoid executing its malicious behavior when it detects that it is being analyzed in a sandbox. This is a common evasion technique used by malware to prevent detection and analysis by security researchers or automated systems.

References: Understanding Cisco Cybersecurity Operations Fundamentals (CBROPS) and other Cisco cybersecurity resources discuss malware analysis and the use of sandbox environments to safely execute and study potential malware. These resources also cover the topic of evasion techniques used by malware to avoid detection.

Symmetric encryption is a type of encryption that uses the same key to encrypt and decrypt data. Asymmetric encryption is a type of encryption that uses a pair of keys: a public key and a private key. The public key can be used to encrypt data, but only the private key can decrypt it, and vice versa. An advantage of symmetric encryption over asymmetric encryption is that it is faster and more efficient for encrypting large amounts of data, such as in sessions or bulk transfers. Asymmetric encryption is slower and more computationally intensive, but it is more secure and suitable for key exchange or digital signatures. References := Cisco Cybersecurity Operations Fundamentals, Module 2: Security Monitoring, Lesson 2.3: Cryptography and PKI, Topic 2.3.1: Cryptography

The situation where endpoint logs show a machine receiving an unusual gateway address and DNS servers via DHCP is indicative of a Man-in-the-Middle (MitM) attack, specifically a DHCP spoofing attack. In this type of attack, an adversary can set up a rogue DHCP server or manipulate the DHCP communication to provide false gateway and DNS information to clients. This allows the attacker to intercept, monitor, or manipulate traffic between the client and the intended gateway or DNS servers2.

References: Cisco’s best practices for network protections and attack identification3, and additional insights on securing networks from DHCP attacks