Cross-site scripting, or XSS, is the correct answer because it involves injecting malicious script into web content that executes in a user's browser. If an application fails to validate or encode input properly, an attacker can cause the browser to run externally supplied JavaScript. This can allow session theft, credential harvesting, browser redirection, page manipulation, or actions performed as the victim. A secure web gateway, or SWG, is a defensive control, not an attack vulnerability. Denial of service focuses on disrupting availability, not controlling a browser through script execution. SQL injection targets backend database queries rather than browser-side script execution. The phrase "externally injected script" strongly identifies XSS as the exploited vulnerability.

Detailed Explanation:A VM escape occurs when an attacker breaks out of a virtual machine's isolation to access the hypervisor. This compromise can allow control of the hypervisor and all other VMs on the host, posing significant security risks. Reference: CompTIA Security+ SY0-701 Study Guide, Domain 3: Security Architecture, Section: "Virtualization Risks and Mitigation".

Detailed Explanation:The Common Vulnerability Scoring System (CVSS) is a standardized metric used to assess the severity of vulnerabilities, aiding organizations in prioritizing their response based on risk.
Reference: CompTIA Security+ SY0-701 Study Guide, Domain 2: Vulnerabilities, Section: "Vulnerability Prioritization and Metrics".

To block signature-based attacks, the Intrusion Prevention System (IPS) must be in active mode. In this mode, the IPS can actively monitor and block malicious traffic in real time based on predefined signatures. This is the best mode to prevent known attack types from reaching the internal network.
Monitor mode and sensor mode are typically passive, meaning they only observe and log traffic without actively blocking it.
Audit mode is used for review purposes and does not actively block traffic.

This scenario describes a partially-known environment penetration test. In CompTIA Security+ SY0-701, penetration testing approaches are commonly categorized as black box (unknown), white box (fully known), and gray box (partially known). A partially-known environment means the tester is given limited information-enough to be realistic and efficient, but not complete details about the infrastructure.
Here, the vendor is assisting an internal red team and is intentionally not provided with extensive infrastructure details, which mirrors a gray-box testing approach. This method balances realism and efficiency by simulating an attacker who has some knowledge (such as credentials, architecture diagrams, or application details) but not full access or documentation.
Passive reconnaissance (A) is an activity within testing, not a testing methodology. Integrated testing (C) refers to coordinated testing involving multiple teams (e.g., red and blue teams) with full cooperation.
Defensive testing (D) focuses on validating defensive controls rather than simulating an attacker's perspective.
Therefore, the correct answer is B: Partially-known environment.