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

The STIX data structure shows apatternfield with this entry:

file:hashes.'SHA-256' = '3299f07bc0711b3587fe8a1c6bf3ee6cbcc14cb775f64b28a61d72ebcb8968d3'

This value is aSHA-256 file hash, a well-knownindicator of compromise (IoC)for identifying malicious files.

Therefore, the correct answer is:

A. SHA256 file hash.

The-hoption in theobjdumpcommand displayssection headersof an object file. According to general usage and command-line documentation, and also explained in digital forensics tools discussions in the CyberOps course, the header information includes details about the name, size, VMA, LMA, file offset, and alignment of each section in the object file. This helps analysts understand how data is stored and organized within compiled files during forensic examinations.

One of the primary challenges of cloud forensics is the inability to physically access the underlying hardware (e.g., the hard drives storing VM or container data). This restricts investigators from performing traditional disk imaging and handling procedures, which are crucial for maintaining evidence integrity. This limitation is widely recognized in cloud forensics frameworks.

Correct answer: C. no physical access to the hard drive.

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.

The syntax in the code snippet includes:

On Error Resume Next– a classic VBScript error-handling directive.

function ... end functionstructure.

Use ofMid(),Chr(), andAsc()functions – all commonly used in VBScript for string manipulation.

CInt()for conversion – typical in VBScript.

These characteristics alignexactly with VBScript, which is frequently used in malicious macros and obfuscated payloads for malware distribution, as covered in the Cisco CyberOps Associate curriculum when analyzing scripts and encoded threats.

The XML (STIX/CybOX format) details anemail-based threatindicator. Specifically:

Theemail addresscontains “@state.gov” (not exact match, so blocking all @state.gov would be overbroad).

Theattachment is a PDFfile with a specifiedMD5 hash: cf2b3ad32a8a4cfb05e9dfc45875bd70.

Theattachment sizeis 87022 bytes.

From a threat mitigation perspective:

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

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

Incorrect options:

Boverreaches by blocking an entire domain without confirming threat context.

Cwould stop all PDFs, which is impractical.

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

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.

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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According to the event log, a suspicious service was installed (DIAOHHNMPMMRgji) with a service file pointing to a remote share (\\127.0.0.1\admin$\EqnBqKWm.exe). This type of activity strongly suggests:

A. Unauthorized system modification: Installation of a service without proper authorization, especially with a random or obfuscated name, directly fits the description of system modification. The use of admin$ (administrative share) further implies this wasn't part of standard operations.

E. Malware outbreak: The use of a service that points to an executable with a seemingly random name and the demand start configuration indicate a potential backdoor or remote-controlled malware. As stated in the Cisco CyberOps Associate guide, event ID 7045 with unusual service names or file paths is a strongIndicator of Compromise (IoC)for malware or persistence mechanisms.

Options like privilege escalation or DoS are not directly evidenced in the event log shown. There's no indication that the LocalSystem account was elevated beyond its default, nor that system resources were overwhelmed (as would be typical in DoS).

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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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.

According to theCyberOps Technologies (CBRFIR) 300-215 study guide, during thepost-incident activityphase, it is critical to analyze lessons learned and update processes to ensure quicker and more efficient response in the future. Specifically:

Introducing a priority rating for incident response workloads(A) helps address the issue of team members being occupied with other tasks and unable to prioritize abnormal system activity. This ensures incidents are handled based on severity, not just workload.

Creating an executive team delegation plan(D) addresses the issue of delays due to unavailability of management for approvals. It ensures alternative decision-makers are available for swift action.

These strategies are based on the NIST SP 800-61 Rev. 2 recommendations and are highlighted in the Cisco guide’s post-incident activity phase (page 418), which emphasizeslessons learnedand how to reduce detection and response times for future incidents.

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 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 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.

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:164.90.168.78and199.19.224.83

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 domainapponline-8473.xyzis 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.

When Web Application Firewalls (WAFs) are configured to block specific patterns (like${), attackers may bypass this using URL encoding (e.g.,%24%7B). In such cases, the WAF must decode these patterns before applying matching rules. EnablingURL decodingensures the WAF recognizes encoded payloads and applies protections appropriately. This is a recommended hardening strategy against bypass techniques for command injection and remote code execution.

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/").

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”.

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 theCyberOps Technologies (CBRFIR) 300-215 study guide). Specifically, in theIdentification and Containmentphases 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.

The scenario describes an attack vector where insiders or malicious actors useremovable 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, usingMulti-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.

The magic number (also known as a magic byte) is a sequence of bytes used to identify the format of a file. For PDF files, the standard magic number is:

25 50 44 46, which translates to%PDFin ASCII. OptionC(255044462d) begins with25 50 44 46, confirming it's a PDF file signature. This is a key forensic detail when performing file type identification and validation of potentially obfuscated or renamed files.

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.

A “malicious insider” is someone within the organization who has authorized access but intentionally misuses that access to extract or exfiltrate data. In this case:

The HR user has legitimate access but deviates from their normal behavior pattern (accessing legal data daily instead of monthly).

The presence of large data dumps and the alert from a threat intelligence platform suggest intentional misuse rather than accidental behavior.

According to the Cisco CyberOps Associate guide, insider threats are identified by behavioral anomalies, especially involving sensitive data access patterns inconsistent with role-based access and historical usage profiles.

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.

The alert box in the screenshot ("HACKED BY 1337") is a classic sign ofCross-Site Scripting (XSS). This occurs when unvalidated input is executed as code in a browser.

To prevent this:

TheCisco CyberOps Associateguide recommendsstrict input validationas the primary defense against XSS and similar web-based injection attacks.

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 alert clearly identifies ET SCAN DirBuster Web App Scan in Progress, referencingSID 2008186, which is a Snort signature that specifically detectsDirBusteractivity. DirBuster is a well-known tool used for brute-forcing hidden directories and files on web servers.

The Cisco CyberOps Associate guide and OWASP both identifydirectory brute-forcingas a reconnaissance technique to find unprotected or misconfigured endpoints on web applications, typically prior to launching deeper attacks.

Therefore, the correct interpretation of the alert is:

C. brute-force attack against directories and files on the target webserver.

In phishing incidents, especially with successful lateral movement (land and expand), the most critical factor is usuallyweaknesses in email security systems—such as lack of advanced phishing detection, weak DMARC/DKIM/SPF policies, or insufficient user behavior monitoring. To prevent recurrence, the root cause analysis must focus on what allowed the phishing email to bypass defenses and how initial credentials were compromised.

This aligns with best practices from the Cisco CyberOps v1.2 Guide underEmail Threat Vectors and Security Control Weaknesses.