300-215 Questions and Answers

YARA rules are pattern-matching rules used to identify malware based on specific strings, conditions, and binary patterns. They are most effective in memory or file scans where analysts search for known indicators or unique signatures via string matching.

Correct answer: C. string matching.

Cisco Firepower Management Center (FMC), when configured with Snort rules, classifies attacks with signature categories such as FILE-OFFICE for Microsoft Office-based exploits. One of the critical threats involving Microsoft Office is a known vector involving Microsoft Graphics, which attackers exploit forremote code execution (RCE). RCE vulnerabilities enable attackers to execute arbitrary commands or code on the target machine—making this classification high-severity.

The alert "FILE-OFFICE Microsoft Graphics remote code execution attempt" is consistent with what Cisco and Snort define for such threats and appears in rulesets addressing vulnerabilities like CVE-2017-0001.

Theroot cause analysisin incident response focuses on identifying theinitial trigger or root causeof the incident to understand how it started and how to prevent recurrence. In this scenario, thephishing email sent to the victim(A) is the initial trigger that led to the employee’s action of clicking the malvertising link, resulting in the malware download.

The other options represent later stages in the incident response cycle, such as detection (SIEM alert, cybersecurity team’s alert) or supporting evidence (email header information), but they do not address the root cause, which is thephishing email itself.

This aligns with theCyberOps Technologies (CBRFIR) 300-215 study guide, which states that identifying theinitial vector of compromiseis critical to theroot cause analysisphase of incident response (Chapter: Incident Response Techniques, page 410-412).

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 PowerShell cmdlet Get-Content reads content line-by-line from a file and is commonly used for processing logs or large text files. When combined with Select-String, it can search for specific patterns (such as "ERROR" or "SUCCESS") within those lines and return a collection of matching objects, including metadata like line number and line content.

Option D uses:

Get-Content –Path: Correct syntax to read the log file from a UNC path.

Select-String “ERROR”, “SUCCESS”: Searches for these terms in each line and returns matching lines as structured output.

The other options (A, B, C) use non-existent or incorrect cmdlets/parameters such as Get-Content-Folder, –ifmatch, –Directory, which are invalid in PowerShell.

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.

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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.

Ghidrais a free and open-source software reverse engineering (SRE) suite developed by the NSA. It includes disassembly, decompilation, and debugging tools specifically designed for analyzing malware and other compiled programs.

The Cisco CyberOps guide referencesGhidraas a top tool for reverse engineering binary files during malware analysis tasks, making it ideal for understanding malicious code behavior at a deeper level.

The alert indicates aWebDAV Stack Buffer Overflow, which is amemory corruptionattack targeting the stack, a common vector forremote code executionordenial-of-service (DoS).

To mitigate such exploits, two effective system-hardening techniques are:

C. Address Space Layout Randomization (ASLR):Randomizes memory addresses used by system and application processes, making it difficult for attackers to predict where their malicious code will be executed.

E. Data Execution Prevention (DEP):Prevents execution of code from non-executable memory regions such as the stack, thus stopping buffer overflow attacks from successfully executing payloads.

Both are well-established protections against stack-based buffer overflow attacks and are strongly recommended in the Cisco CyberOps Associate guide and general security best practices.

Dynamic malware analysis involves executing the malware in a controlled environment to observe its behavior, such as file creation, network traffic, or system modifications. Asandboxis designed for this purpose—it safely executes and monitors suspicious code without risking the host system. The other tools (Decompiler, Unpacker, Disassembler) are primarily used in static analysis.

Correct answer: D. Sandbox

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A disassembler is a forensic and reverse engineering tool that translates machine-level code (binary) back into human-readable assembly language. This is used during static malware analysis to understand how the malware is constructed and what it is designed to do without actually executing the code.

According to theCyberOps Technologies (CBRFIR) 300-215 study guide, “Disassembler tools are used to assist with reverse malware engineering by allowing a security professional to examine the binary and understand the functionality of the malware code”.

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Input validation (A) is a critical countermeasure to defend against command injection and related vulnerabilities, as discussed in the Cisco guide. Proper validation ensures that malicious commands or payloads are not accepted or executed by the web application.

File integrity monitoring (E) helps detect unauthorized changes such as log deletion or binary modification, making it a crucial tool in recognizing and investigating tampering attempts.Blocking port 443 (B) would disable HTTPS and is not a practical solution. Antivirus (C) does not prevent form-based application attacks, and merely updating the application (D) may not be sufficient without addressing the underlying input validation flaw.

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The incident stems from a policy-level issue rather than a technical vulnerability. According to incident response best practices, the priority should be to review and update firewall rules and ensure that the network security policy aligns with the principle of least privilege and correct access segmentation.

Volatility is an open-source memory forensics tool specifically designed for memory analysis. It allows forensic investigators to inspect memory dumps for running processes, hidden processes, injected code, and malicious activity in memory.

As per the Cisco CyberOps Associate study guide, “Volatility helps security professionals with both incident response and malware analysis. It can identify processes, registry artifacts, network connections, and memory-resident malware”.

While Memoryze (D) is also a memory analysis tool, Volatility is the more recognized, command-line driven tool used widely in industry and is directly highlighted in the curriculum.

Cisco Secure Endpoint (formerly AMP for Endpoints) offers features like:

File trajectory: to track file behavior and spread across endpoints.

Orbital Advanced Search: for querying endpoint data to detect threats in real time.

In therecovery phase, the goal is to restore affected systems to normal operations and ensure the threat has been completely eradicated. According to the CyberOps Associate guide:

"This phase may include restoring data from clean backups, replacing compromised systems, and the re-installation of the Operating System (OS) and applications".

Also:

"During recovery, scanning hosts with updated antivirus and removing vulnerabilities ensures systems do not get reinfected".

YARA rulesare primarily used for malware classification and detection based onbinary pattern matchingwithin files. They describe sequences of bytes, strings, and other file characteristics found in malicious binaries.

The Cisco CyberOps Associate guide explains:"YARA rules operate by inspecting binary data using conditions and string matches to identify specific patterns that indicate known malware samples.".

The best immediate step during a DDoS attack against an Apache web server is to inspect theaccess logs, which will show which IP addresses are making requests, their frequency, and potential patterns of abuse. As covered in the Cisco CyberOps material, "Apache logs can reveal the IPs responsible for flooding the service with requests". The commandsudo tail -100 /var/log/apache2/access.logallows quick review of recent activity.

The Cisco study material recommends integrating automation for log/event collection and contextual analysis to reduce detection delays and ensure rapid identification of anomalies. It also emphasizes the need for pre-defined roles and documented steps in anIncident Handling Playbook, following NIST SP 800-61 Rev.2 standards, to improve consistency and readiness during incidents.

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 Python code snippet:

Usessocket.socket(AF_INET, SOCK_STREAM), which indicatesTCP communication

Connects to a remote server (192.168.1.10on port 80)

Sends a manual HTTPGETrequest

Receives the response usings.recv()

This is a classic example ofTCP/IP socket programming, specifically creating asimple TCP clientto communicate with a web server. It does not monitor traffic or crawl websites — it sends a crafted request and prints the response.

Thus, this code best fits:

D. socket programming listener for TCP/IP communication.

According to theCyberOps Technologies (CBRFIR) 300-215 study guidecurriculum, when analyzing suspicious behavior—especially when scripts or shell commands are executed from applications like Word (which is uncommon)—the encoded PowerShell payload must be decoded to determine if malicious intent is present. Deobfuscation is a critical step in identifying command-and-control behavior, persistence, or malware execution paths.

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YARA rulesare designed to identifyfilesthat match specific patterns, strings, or binary characteristics.

The Cisco CyberOps guide states:

“YARA helps researchers and analysts identify and classify malware samples based on textual or binary patterns”.

The string shown is long, alphanumeric, and includes both uppercase and lowercase letters with numbers—characteristics of Base64 encoding. This format is widely used to obfuscate payloads in malicious scripts, particularly in phishing or malware campaigns. Base64 encoding is also supported by Python and other platforms for data transformation.

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The safest and most effective approach is to isolate the files and subject them to heuristic and behavioral analysis. This can reveal obfuscated malware or unauthorized data storage techniques, even if signature-based antivirus fails to flag them.

Using adifferent IP addressto disguise the origin of an attack is the definition ofIP spoofing.

“Spoofing involves falsifying data, such as IP or MAC addresses, to hide the source of malicious activity.” — Cisco CyberOps guide

The Wireshark output shows SMB protocol transactions, including NT Create AndX Response and Write AndX Response, indicating the transfer of files or objects. SMB (Server Message Block) is a protocol used for file sharing and printer access in Windows networks. The log does not indicate phishing or redirection behavior but rather normal SMB communication such as accessing files or shared resources.

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TheCisco Secure Firewall Threat Defense (Firepower)includes advanced capabilities such as intrusion prevention, URL filtering, and deep packet inspection. According to the CyberOps guide, it can detect and block C2 communications by analyzing traffic patterns and comparing them to threat intelligence data. The guide specifically states: "Advanced solutions such as Firepower provide detection capabilities for command and control (C2) traffic by identifying unusual outbound connections and behavioral anomalies".

The eradication phase in incident response involveseliminating the root cause of the incidentand strengthening defenses to prevent reoccurrence. In this case:

Intrusion Prevention System (D): Adding new rules to the IPS to detect and block malicious activity on TCP/135 is a direct eradication step to remove the threat’s entry point and prevent future attacks.

Centralized User Management (C): Hardening user accounts, removing unnecessary permissions, and applying tighter authentication/authorization measures helps eliminate the possibility that threat actors could exploit weak or mismanaged accounts to continue accessing the system.

Althoughanti-malware software (A)andenterprise block listing (E)are valuable, themost direct eradication stepshere specifically involve managing network access (via IPS) and strengthening user controls (via centralized user management), especially when TCP/135 (MSRPC endpoint mapper) can be used to enumerate services and potentially access vulnerable endpoints remotely.

This aligns with best practices outlined in incident response frameworks (such as the NIST SP 800-61 and referenced resources), which emphasizeclosing the exploited entry points(in this case, TCP/135) andremoving any lingering access pointsthrough user management and network control enhancements.