300-215 Conducting Forensic Analysis and Incident Response Using Cisco CyberOps Technologies (CBRFIR) Questions and Answers

Cisco Secure Malware Analytics (formerly Threat Grid) enables deep file behavior analysis, including TCP/IP stream analysis and behavioral indicators such as file system activity, process injection, registry changes, and command and control communication. These are essential in understanding what the suspicious file does post-execution, especially given the described behavior of creating a fake folder and outbound connection attempts.

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Once an incident has occurred, the appropriate course of action is to engage the organization ' s Incident Response (IR) plan. This is a structured approach to contain, analyze, and eradicate threats before they spread across the network.

The Cisco CyberOps Associate study guide emphasizes:

“Incident response and handling are essential within an organization… The main objective of implementing an incident handling process is to reduce the impact of a cyber-attack, ensure the damages caused are assessed, and implement recovery procedures”.

In particular, the containment phase of IR is focused on isolating the threat and preventing lateral movement or further compromise.

Options such as " root cause " or " attack surface " are relevant at later stages of analysis and mitigation, not immediate containment. Therefore, the correct answer is C.

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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Since the phishing email originates from a known compromised cloud provider (XYZCloud), the correct immediate action for the security analyst is to determine the broader scope of exposure. This involves checking whether other users in the organization received similar emails from the same potentially malicious source. Therefore, querying for emails from the IP address ranges or SMTP domains linked to XYZCloud is essential for identifying other possible attack vectors.

This step aligns with the containment phase of the incident response lifecycle, as outlined in the CyberOps Technologies (CBRFIR) 300-215 study guide, where threat hunting and log analysis are used to determine the extent of compromise and prevent lateral movement or further exposure. Only after the scope is understood should remediation or reporting actions follow.

Generic Routing Encapsulation (GRE) is a tunneling protocol used to encapsulate a wide variety of network layer protocols inside point-to-point connections. If packets encapsulated with GRE are bypassing monitoring tools, it ' s likely due to tunneling—where payloads are hidden within another protocol. Tunneling can obscure malicious content or lateral movement in a network and is a common method used in data exfiltration.

Comprehensive and Detailed Explanation:

The exhibit contains STIX (Structured Threat Information Expression) formatted threat intelligence indicating:

A phishing indicator related to the domain: apponline-8473.xyz

Associated malicious IP addresses: 164.90.168.78 and 199.19.224.83

Labelled as " malicious-activity " with " xfe-threat-score-10 "

Based on this:

Option B is correct: The IP addresses explicitly listed in the pattern field should be blacklisted to prevent command-and-control or malicious connections.

Option C is correct: The domain apponline-8473.xyz is also listed and flagged as involved in phishing, so DNS and firewall rules should block access to and from this domain.

Options A and E are too broad or speculative; the data specifies a specific domain, not a generic block on all emails or URLs. Option D refers to a label used for classification and not a directly actionable item.

Therefore, the correct answers are: B and C.

YARA rules are designed to identify files that 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”.

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.

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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The XML (STIX/CybOX format) details an email-based threat indicator. Specifically:

The email address contains “@state.gov” (not exact match, so blocking all @state.gov would be overbroad).

The attachment is a PDF file with a specified MD5 hash : cf2b3ad32a8a4cfb05e9dfc45875bd70.

The attachment size is 87022 bytes.

From a threat mitigation perspective:

A is correct: Updating AV to block or flag files matching the malicious hash is a standard response.

D is correct: The email address context and hash together provide a precise rule for blocking—this prevents false positives.

Incorrect options:

B overreaches by blocking an entire domain without confirming threat context.

C would stop all PDFs, which is impractical.

E is incorrect; there is no indication that the hash appears in the subject line.

In highly sensitive environments such as secure government networks, the presence of anomalous DLL injection, beaconing to known interception points, and signs of encrypted data exfiltration constitutes a critical incident. The appropriate response in such classified contexts involves:

Invoking a pre-established, classified incident response protocol,

Immediately notifying national cyber defense operatives (such as national CERT or military cyber command),

Prioritizing containment to stop lateral spread,

Proceeding with eradication of malware or backdoors.

This response sequence aligns with the high-severity, immediate-response model described in the Cisco CyberOps Associate v1.2 curriculum under national defense and classified incident frameworks. The study guide emphasizes the importance of stakeholder communication and multi-agency coordination during advanced persistent threat (APT) intrusions involving critical infrastructure or defense systems.

Process injection is a tactic where malicious code is inserted into the memory space of another process, enabling it to run with the privileges and context of a legitimate application. The Cisco study guide explains that this method allows malware to " hide in plain sight " within trusted processes and evade endpoint detection and response (EDR) tools.

It specifically notes: " Process injection techniques allow malware to execute within the memory space of a legitimate process, avoiding detection and taking advantage of the process ' s permissions. " .

The scenario describes an attack vector where insiders or malicious actors use removable media (USB drives) to introduce malware, which then connects to external sources to exfiltrate data and compromise systems.

Option B addresses the human factor and technological prevention. The guide stresses the need for training to ensure users are aware of social engineering and removable media risks. Blocking the use of USB drives at a system level further minimizes attack vectors.

Option E, using Multi-Factor Authentication (MFA), provides an additional layer of defense. Even if credentials are stolen, MFA can prevent the attacker from accessing sensitive internal resources without the second authentication factor.

These controls align with defense-in-depth strategies recommended in the Cisco CyberOps Associate curriculum to combat insider threats and external unauthorized access.

TCPdump is a command-line packet analyzer used to capture and inspect network packets. As described in the study guide, " tcpdump is a command-line interface tool that is used to capture packets on a network. It is a very powerful and popular network protocol analyzer " . The tool allows cybersecurity professionals to analyze headers and payloads of network traffic, making it valuable in forensic investigations and network diagnostics.

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.

The hexadecimal representation in the exhibit does not match the Base64 encoding format, which uses ASCII characters (A-Z, a-z, 0-9, +, /) and often includes padding with = . This string is clearly hex and is more aligned with Charcode , where hexadecimal values represent individual characters based on ASCII values.

The Cisco CyberOps Associate guide refers to such encodings during forensic analysis and emphasizes identifying patterns in memory dumps, payloads, or logs. " Security professionals often decode hexadecimal strings to reveal ASCII representations, particularly when inspecting encoded payloads or character obfuscation techniques used in malware " .

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/ " ).

Comprehensive and Detailed Explanation:

From the exhibit, Cisco Secure Malware Analytics (formerly Threat Grid) has captured outbound HTTP POST communication to the IP address 51.38.124.206 on port 80. This destination is highlighted in the analysis under “Outbound HTTP POST Communications,” indicating exfiltration behavior or command-and-control (C2) signaling.

Key indicators:

The report shows that binary data was POSTed to this IP.

The source system generated 22 packets and sent 6,192 bytes.

The system has flagged the behavior with a severity of 25 and confidence of 25—suggesting that this is an IoC worth acting on.

Therefore, the artifacts suggest that the destination IP 51.38.124.206 is involved in malicious activity, and the correct answer is:

Answer: A. Destination IP 51.38.124.206 is identified as malicious.

According to the CyberOps Technologies (CBRFIR) 300-215 study guide curriculum, command-and-control (C2) communication is a strong indicator that a system has already been compromised and is actively under the control of an attacker. Sudden outbound traffic to high-risk regions and resolution of known malicious domains are high-confidence signs of an active threat. Therefore, prioritizing detection and disruption of this outbound traffic is critical to prevent further damage or data exfiltration.

While monitoring vulnerability exploitation (B) and gathering port scan data (D) are also valuable, they are more preventive or forensic in nature. The most immediate threat—and therefore the top priority—is stopping active C2 communications.

According to the Cisco Certified CyberOps Associate guide (Chapter 5 - Identifying Attack Methods), attachments in emails—especially with file extensions like .xlsm —are high-risk indicators when analyzing suspicious or phishing emails. Malicious actors often use macro-enabled Excel files ( .xlsm ) as a payload delivery mechanism for malware or other exploits. These attachments are typically disguised as legitimate content such as refunds or invoices to trick the recipient into opening them.

The presence of “Card_Refund_18_6913.xlsm” is a strong Indicator of Compromise (IoC) , as .xlsm files can contain VBA macros capable of executing malicious code. This matches exactly with examples provided in the study material discussing how macro-based payloads are delivered and recognized.

Hence, option C is the most direct indicator of attack in this email.

When suspicious activity is detected on a workstation, immediate steps need to be taken to preserve evidence and prevent further compromise:

Disconnecting the system from the network (C) is crucial to stop potential exfiltration of data or ongoing communications with a command-and-control server. This isolation prevents further spread or damage while preserving the state of the compromised system for further investigation.

Taking an image of the workstation (E) is part of the forensics acquisition process. It involves creating a bit-by-bit copy of the system’s disk, which preserves all evidence in its current state. This allows for thorough forensic analysis without affecting the original evidence.

These steps align with the best practices outlined in the incident response and forensics processes (as described in the CyberOps Technologies (CBRFIR) 300-215 study guide). Specifically, in the Identification and Containment phases of the incident response cycle, it’s emphasized that isolating the system and preserving evidence through imaging are critical to ensuring both containment of the threat and successful forensic investigation.

To prepare a post-incident report, the cause of the incident (what enabled it) and the effect (what damage was done) are the primary components analyzed first. This allows teams to understand vulnerabilities exploited and the consequences, forming the basis for corrective action.

The Cisco CyberOps guide recommends beginning with root cause analysis followed by impact assessment to guide future prevention strategies.

The eradication phase in incident response involves eliminating the root cause of the incident and 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.

Although anti-malware software (A) and enterprise block listing (E) are valuable, the most direct eradication steps here 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 emphasize closing the exploited entry points (in this case, TCP/135) and removing any lingering access points through user management and network control enhancements.

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 with directory fuzzing , a reconnaissance technique used by attackers (or automated tools) to map out web direc tory 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).

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 a SYN 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.

The countermeasure for this scenario, as highlighted in the CyberOps Technologies (CBRFIR) 300-215 study guide under Network-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.

The Apache access logs in the exhibit show a sequence of HTTP requests and responses indicative of a malicious upload via WordPress:

A POST to:

/wp-admin/admin-ajax.php with parameters that include uploading r57.php (a known PHP web shell).

The uploaded file name appears as r57.php in: → & name=%5B%5D=r57.php & FILES...

There are plugin installation and activation attempts, specifically for:

file-manager plugin: → plugin=file-manager & ...

Which is known to be vulnerable and exploited for file uploads.

GET requests to:

/wp-content/57.php and variations such as 57.php?28 — This suggests that r57.php was successfully uploaded and is being accessed.

These logs reveal that:

D. The attacker used the WordPress file manager plugin to upload r57.php — confirmed by plugin activity and file uploads.

B. The attacker uploaded the WordPress file manager trojan — as evidenced by the direct access to /wp-content/57.php (r57 shell variant).

Other options are invalid or speculative:

A is correct in identifying r57 as a web shell, but the logs don ' t show privilege escalation.

C mentions brute force and SQL injection, which are not indicated here.

E assumes legitimate access — logs suggest exploitation, not standard login.

The event log shown in the exhibit is Event ID 104 , which in Windows indicates " The audit log was cleared. " This is a significant indicator of log 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 of log tampering .

During the initial phase of incident response, the two key actions are:

Disconnecting the server (B) to contain the threat and prevent lateral movement or further exfiltration.

Reviewing network logs (E) to understand the timeline and scope of the attack.

These are emphasized in the containment and detection stages of the incident response lifecycle outlined in NIST 800-61 and covered in the Cisco CyberOps training.

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Fileless malware resides in memory and does not leave traditional file artifacts, making it difficult for antivirus solutions to detect. The most effective next step is to isolate the endpoints to prevent lateral movement and perform memory forensics to capture volatile data and identify any running malicious processes.

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 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 alert indicates a WebDAV Stack Buffer Overflow , which is a memory corruption attack targeting the stack, a common vector for remote code execution or denial-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.

The best immediate step during a DDoS attack against an Apache web server is to inspect the access 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 command sudo tail -100 /var/log/apache2/access.log allows quick review of recent activity.

/etc/shadow : This file stores encrypted passwords and password aging information, including the date of the last password change (stored as the number of days since January 1, 1970). It is only readable by the root user, making it the primary source for forensic auditing of local password changes.

The correct registry path to investigate user profiles and login details is:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\WindowsNT\CurrentVersion\ProfileList

This location stores information about each user profile on the machine, including login activity and the LastWrite time for forensic tracking.