Pass the Cisco CyberOps Professional 300-215 Questions and answers with CertsForce

In VMware ESXi systems, the vmksummary.log file is responsible for capturing general system events, including uptime, reboot statistics, and key service-related issues. It serves as a valuable source for troubleshooting persistent or unexplained system behaviors.

The Cisco CyberOps study guide references log file paths used in system diagnostics and incident response, and for authentication-related issues on ESXi where standard logs don't yield insights, vmksummary.log is the recommended next source for identifying systemic service faults or anomalies.

—

The most relevant log for system-level events such as memory exhaustion and shutdown is/var/log/messages.log, which contains kernel and service-level logs including OOM (Out-Of-Memory) events.

As detailed in Linux investigations:

"Logs located in/var/log/messagesprovide critical system error reporting including shutdowns, memory errors, and service failures".

The code in the exhibit is written in Python. Here’s how we can confirm:

The function definition uses Python syntax: def function_name(args):

It uses the b64encode and decode functions — typical of Python’s base64 module.

Data structures such as dictionaries are used with curly braces (e.g., form_data = {entry1: enc1, ...}).

The conditional syntax uses “if r.status_code == 200:” which is Pythonic.

The request object “r = post(...)” and use of headers show standard use of the Python requests library.

This type of script is typical in exfiltration scenarios where encoded information is sent via a web form (in this case Google Forms), bypassing detection systems.

From the Wireshark capture:

A (iraniansk.com): This domain isnot a known legitimate resourceand is hosting a suspicious file named “Fy.exe,” strongly indicative of amalware distribution domain.

D (Fy.exe): TheContent-Disposition: attachment; filename="Fy.exe"header explicitly signals abinary executabledownload, a key indicator in Emotet campaigns.

WhileContent-Type: application/octet-stream(E) is typical of binary data transfers, it isnot uniqueto malware and cannot by itself serve as a strong IoC. Thenginx server (B)andcookie/hash string (C)similarly do not uniquely indicate compromise.

The provided log file contains multiple HTTP GET requests attempting to access various directories and files on the web server such as:

/balance

/security

/finance

/secret

/opt

/fuzzer/admin

These requests appear to be sequential, systematically targeting commonly used file and directory paths. The response codes are mostly 404 (Not Found) and a few 301s, indicating that the requester is trying different permutations of paths to discover hidden or vulnerable endpoints. This behavior is consistent withdirectory fuzzing, a reconnaissance technique used by attackers (or automated tools) to map out web directory structures by sending a high volume of crafted requests to guess hidden or unlinked directories and files.

This is distinct from DDoS (which would manifest as volume-based access issues), SQL injection (which targets specific parameters within requests), or botnet infection (which generally involves command-and-control communication or massive traffic floods).

The event log shown in the exhibit isEvent ID 104, which in Windows indicates"The audit log was cleared."This is a significant indicator oflog tampering, a common post-exploitation technique used by attackers to hide their tracks after exfiltrating data or performing unauthorized actions.

The Cisco CyberOps Associate guide mentions:

"Log deletion events, especially Event ID 104, should be treated as potential evidence of malicious activity attempting to cover tracks".

Combined with large data dumps to network shares, this indicates not only unauthorized activity but also deliberate efforts to erase forensic evidence—characteristic oflog tampering.

The root cause analysis report’s main goal is to identify what allowed the ransomware to successfully infect systems. The Cisco CyberOps Associate guide emphasizes the importance of uncovering and mitigating the actual vulnerabilities that were exploited during an incident. These could include outdated software, unpatched systems, or poor access control. While understanding the encryption technique or C2 server is helpful for threat intelligence, it does not address the root cause.

The guide states:

"Effective IR helps professionals to leverage the information collected from a security incident to better understand the intrusion and its functionality… this data helps the security team to be better prepared and equipped to handle future incidents".

Identifying the exploited vulnerabilities enables future prevention strategies such as patch management, configuration hardening, and reducing attack surfaces.

—

The XML structure shows that:

The file namestarts with:"Final Report"

The file extensionequals:"doc.exe"

Together, this forms"Final Report.doc.exe"— a knowndouble-extensiontechnique used todisguise executablesas benign documents. This is a red flag in email forensics, commonly linked tomalware distribution, and explicitly covered in the Cisco CyberOps study material as a typicalevasion methodfor malicious attachments.

This STIX (Structured Threat Information eXpression) JSON snippet provides two key elements relevant for IOC (Indicator of Compromise) analysis:

The indicator pattern shows a suspicious URL:→ "pattern": "[url:value = 'http://x4z9rb.cn/4712/']" This is the actual IOC that can be used for detection.

The type of object that the indicator relates to:→ "type": "malware"→ "name": "x4z9arb backdoor"This indicates the nature of the threat associated with the IOC is malware.

Therefore, the threat is "malware" and the associated indicator (IOC) is the URL: http://x4z9rb.cn/4712/

Option A correctly captures both the IOC category ("malware") and the indicator value ("http://x4z9rb.cn/4712/").

In the provided Wireshark capture, we see multiple TCP SYN packets being sent from different source IP addresses to the same destination IP address(192.168.1.159:80)within a short time window. These SYN packets do not show a corresponding SYN-ACK or ACK response, indicating that these TCP connection requests are not being completed.

This pattern is indicative of aSYN flood attack, a type of Denial of Service (DoS) attack. In this attack, a malicious actor floods the target system with a high volume of TCP SYN requests, leaving the target's TCP connection queue (backlog) filled with half-open connections. This can exhaust system resources, causing legitimate connection requests to be denied or delayed.

Thecountermeasurefor this scenario, as highlighted in theCyberOps Technologies (CBRFIR) 300-215 study guideunderNetwork-Based Attacks and TCP SYN Flood Attacks, involves:

Increasing the backlog queue: This allows the server to hold more half-open connections.

Recycling the oldest half-open connections: This ensures that legitimate connections have a chance to be established if the backlog fills up.