Cisco CyberOps Associate 200-201 (200-201) — Questions 901–975

The first action when a host is infected with ransomware is to isolate it from the network to prevent lateral movement and further encryption of shared resources. Ransomware often uses SMB, RDP, or other network protocols to spread, so disconnecting the host (e.g., by disabling the switch port or unplugging the cable) stops the propagation immediately. This aligns with the NIST incident response framework's containment phase, which prioritizes stopping the attack before any remediation.

Legal counsel advises on data breach notification laws and regulatory requirements.

Full packet capture (PCAP) provides the most detailed information because it records the entire raw network packet, including headers and the complete application-layer payload. This allows deep inspection of protocols like HTTP, DNS, or SMTP at the byte level, which is essential for detecting malware, data exfiltration, or application-specific anomalies.

The access list applied inbound on the external interface denies the packet because the source IP 10.0.0.1 is a private RFC 1918 address, which is typically blocked by a standard or extended ACL to prevent spoofed or internal traffic from entering from outside. Since the packet matches a deny entry (either explicitly or implicitly via the implicit deny all at the end of the ACL), the router drops it without forwarding.

DNS exfiltration encodes data in subdomain queries. The data is sent to a DNS server controlled by the attacker, who extracts it from the logs.

A drive-by download typically exploits a browser or plugin vulnerability to silently execute code on the host. Once compromised, the malware often establishes command-and-control (C2) communication, which manifests as unusual outbound network connections to suspicious IP addresses or domains on non-standard ports (e.g., TCP 4444, 8080). Analyzing netstat output or firewall logs for unexpected outbound traffic is a primary indicator of such post-exploitation activity.

Verifying file integrity involves computing a cryptographic hash (e.g., SHA-256) of the downloaded file and comparing it to the hash provided by the publisher. If the hashes match, the file has not been altered; any tampering would produce a different hash value. This is a standard integrity check, not a confidentiality or authentication mechanism.

Passive reconnaissance involves gathering information without directly interacting with the target, such as searching public records and social media.

The unauthorized modification of patient records violates integrity, which ensures data has not been altered by unauthorized entities. The ransomware attack that encrypted the database and made it inaccessible for three days violates availability, which ensures systems and data are accessible when needed. These two incidents directly compromise the CIA triad principles of integrity and availability.

PCI DSS is the Payment Card Industry Data Security Standard, which applies to organizations that handle credit card data.

The immediate priority is to stop the active data exfiltration and prevent further exploitation. Since the IPS was configured to 'alert' only, it did not block the malicious traffic. Blocking the attacker's IP at the firewall with a temporary drop rule is the fastest way to sever the attacker's access to the web server and stop the ongoing data theft, containing the incident while preserving forensic evidence.

HR is involved in insider threat cases due to employee relations.

The alert triggered but there is no actual attack (false positive). Since the scanner is legitimate, it is not malicious.

Tier 2 conducts deeper investigation, including malware analysis and correlation with other data.

Data exfiltration often involves transferring large volumes of data to an unknown external IP during off-hours (e.g., 3 AM) to evade detection. This behavior deviates from normal business patterns and is a classic indicator of a data breach or insider threat.

The /proc/[pid]/cmdline file contains the full command line used to start the process, including arguments. This helps verify if a process was launched with suspicious parameters.

Post-incident activities include identifying improvements, updating the IR plan, and creating metrics.

High entropy and a sparse import table strongly suggest the file is packed or encrypted. Packers often compress the original code, raising entropy and obfuscating imports.

The traffic is encrypted over TCP port 443 (HTTPS), so the analyst cannot determine the content or legitimacy of the data transfer without decrypting or inspecting the SSL/TLS handshake. Capturing a packet trace allows the analyst to examine the TLS handshake details, such as the server certificate, cipher suites, and SNI, which can reveal whether the external IP is a legitimate service or an unauthorized endpoint. This step is non-disruptive and provides forensic evidence before taking any blocking or quarantine actions.

RDP uses TCP port 3389 and is frequently targeted by attackers attempting to gain remote access.

winlogon.exe spawning cmd.exe is unusual and may indicate an attacker used Sticky Keys or similar accessibility feature abuse (sethc.exe) to gain a command prompt at the login screen. Normal winlogon does not launch cmd.exe as a child.

The ACL in the exhibit (assuming it is a standard or extended ACL with a permit statement for TCP port 80 to host 10.0.1.10 and an implicit deny all) explicitly permits only HTTP traffic (TCP port 80) to the destination host 10.0.1.10. All other traffic is denied by the implicit deny all at the end of the ACL, making option C correct.

User-specific cron jobs are stored in /var/spool/cron/crontabs/ (or /var/spool/cron/). /etc/crontab is system-wide, /etc/cron.d is system-wide directories, and /etc/cron.hourly are scripts. The user-specific location is under /var/spool/cron/.

Capturing a memory dump preserves volatile evidence (e.g., running processes, network connections, and in-memory credentials) that is critical for forensic analysis of a suspected credential theft incident. This aligns with the NIST SP 800-86 forensic process, where memory acquisition is prioritized before any system shutdown or network changes to avoid losing evidence of the attacker's active session or malicious code.

The vulnerability allows an attacker to upload a malicious file (e.g., a web shell) and then execute it on the server, which is the definition of remote code execution (RCE). This occurs because the application fails to validate file types, contents, or execution permissions, enabling arbitrary code to run in the server's context.

The Run keys under HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run and HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run are standard locations where Windows executes programs automatically at user logon. Malware commonly writes entries to these keys to achieve persistence, making them critical for host-based analysis.

A port scan typically sends SYN packets to multiple ports; responses indicate open ports. The lack of completed handshakes suggests a scan, not an attack.

A port scan targeting multiple ports on a single external IP is the classic behavior of network mapping tools like Nmap or Masscan. These tools systematically probe ports to discover open services, which is distinct from the random or sequential scanning patterns of malware or the limited connections of normal user activity.

A DDoS attack floods the target with traffic from multiple sources, overwhelming network resources and causing legitimate requests to time out or be dropped. This results in slow network performance and service unavailability as the system struggles to process the excessive load. The distributed nature of the attack makes it difficult to mitigate with simple IP-based filtering.

Data classification and handling procedures are fundamental to any data security policy. Topology, antivirus, and contacts are supporting but not the most critical.

Prefetch files in Windows record metadata about application launches, including the executable path, run count, and last run timestamp. During host-based analysis, an analyst can examine these .pf files to determine which executables have been executed, how often, and when, providing crucial evidence of file execution activity.

Interactive shell commands over TCP indicate a reverse shell, where the attacker has a command shell on the victim.

NetFlow records from the border router provide aggregated metadata (source/destination IP, port, protocol, timestamps) that can reveal the periodic 60-second beaconing pattern to the malicious domain and the volume of outbound connections on port 443. Unlike DNS logs, NetFlow captures the actual connection attempts regardless of DNS resolution, making it ideal for identifying regular, repetitive outbound flows.

Both HKLM and HKCU Run keys are commonly used for persistence.

Wireshark's 'Export Objects' feature allows you to extract files (e.g., HTTP objects, SMB files, or other application-layer payloads) from a PCAP file. This is essential for further analysis of malware or data exfiltration, as it reconstructs the original files from the captured network streams without needing to replay the traffic.

An inbound connection from an external IP to a MySQL server (port 3306) is highly suspicious — MySQL is a database service that should never be exposed directly to the internet. The immediate best action is to block the external IP at the firewall to prevent potential exploitation, data exfiltration, or brute-force attacks. This aligns with the principle of least privilege and defense-in-depth, as database servers should only accept connections from trusted internal hosts.

Requiring multi-factor authentication for all RDP connections adds a critical layer of security, making it much harder for attackers to gain access even if credentials are compromised.

The correct Snort rule header format is: alert tcp !$HOME_NET any -> any 21. It alerts on TCP traffic from any IP not in $HOME_NET to any destination on port 21 (FTP).

The correct order is Preparation, Detection and Analysis, Containment Eradication and Recovery, and Post-Incident Activity.

NetFlow records (B) are a common source of security event data in a SIEM because they provide detailed metadata about network flows, including source/destination IPs, ports, protocols, and byte counts. SIEMs ingest NetFlow to detect anomalies, such as data exfiltration or beaconing, by analyzing flow patterns rather than full packet payloads. This makes NetFlow a standard telemetry source for network visibility and threat hunting.

Initial triage and identification of incidents occur in the Detection and Analysis phase.

IP addresses are a fundamental type of Indicator of Compromise (IoC) because they directly identify the network location of a malicious host, such as a command-and-control (C2) server or a source of an attack. Security analysts use IP addresses in threat intelligence feeds and SIEM queries to correlate logs and detect inbound or outbound connections to known malicious hosts.

Snort signature-based IDS alerts on matching rules. This alert indicates a connection from an internal host to a known malicious IP address, likely a command-and-control server.

A false positive occurs when the IPS incorrectly identifies legitimate traffic as malicious based on its signature. In this case, the SQL injection signature is matching benign web requests that contain patterns resembling SQL syntax (e.g., 'SELECT', 'DROP'), causing the IPS to drop valid packets. This is a common issue with signature-based detection systems that lack contextual analysis.

A firewall is a technical control because it uses software or hardware mechanisms—such as packet filtering, stateful inspection, or application-layer filtering—to enforce security policies and block unauthorized traffic. Technical controls are implemented through technology systems (e.g., routers, firewalls, IDS/IPS) rather than through physical barriers or administrative procedures.

DNS tunneling exploits the DNS protocol to exfiltrate data by encoding it in DNS queries and responses. Raising the message-length maximum to 4096 bytes allows the DNS inspection engine to inspect larger DNS payloads, which is necessary to detect tunneling attempts that use long TXT or other resource records to carry data. The current lower limit may allow tunneled data to pass undetected because the inspection engine truncates or ignores oversized messages.

The SIEM rule specifically correlates the creation of a user account followed by its addition to a privileged group within a short time window. This sequence directly maps to the definition of privileged account creation and elevation, where a new account is granted administrative rights. The rule does not require any other malicious activity like data theft or lateral movement to trigger.

Normally, winlogon.exe does not spawn cmd.exe; this could indicate a 'sticky keys' (sethc.exe) persistence or other accessibility tool abuse where cmd.exe replaces the debugger.

PowerShell.exe (PID 2792) is the likely malicious process because it has an established HTTPS connection (TCP port 443) to an external server at 192.168.1.50. PowerShell is a powerful scripting tool often abused by attackers to execute arbitrary code, download payloads, or establish command-and-control (C2) channels over encrypted HTTPS, which can evade detection by traditional signature-based security tools.

Syslog severity levels range from 0 (Emergency) to 7 (Debug). Severity 3 corresponds to 'Error', which indicates error conditions that require attention but are not immediately critical. This is defined in RFC 5424, where level 3 is explicitly labeled 'Error' and is used for conditions such as configuration failures or service degradation.

Pass-the-hash uses NTLM hashes for authentication, and SMB brute force involves trying multiple passwords or hashes. Both can produce multiple failed attempts then success.

The IDS alerts indicate the same source IP is communicating with a known malicious domain (evil.com) using a suspicious user-agent string. This pattern of repeated connections to a known bad destination is characteristic of malware beaconing or command-and-control (C2) traffic, not a false positive or benign activity.

Establishing a baseline requires capturing traffic during a period of normal operation, typically over a week, to account for daily and weekly usage patterns. This baseline represents the typical volume, protocol mix, and flow characteristics, enabling the analyst to later detect deviations that may indicate security incidents. Using a representative sample from normal conditions is the foundational step in anomaly-based monitoring.

HIDS are installed directly on a host and have direct access to the host's operating system, allowing them to monitor local system events such as file system changes, registry modifications, and process activity. This granular visibility is a key advantage over NIDS, which only sees network traffic and cannot inspect internal host state.

The Run registry key under HKEY_LOCAL_MACHINE specifies programs that run for all users at logon, while HKEY_CURRENT_USER is per-user. HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Run is the most common location for malware persistence.

Symmetric encryption, asymmetric encryption, and TLS (which uses both) provide confidentiality. Hashing does not.

The first step when a legitimate-seeming email attachment is flagged as malicious is to verify its authenticity with the sender. This aligns with the security policy's requirement to scan attachments while avoiding unnecessary disruption to business operations. Contacting the customer confirms whether the file was intentionally sent and is safe, allowing the analyst to make an informed decision before taking further action.

DNS tunneling encodes data within DNS queries and responses, often using small packets to evade detection. A high volume of small packets from an internal IP to a single external IP on port 53, without corresponding internal DNS server traffic, is a classic indicator of data exfiltration via DNS tunneling.

Large DNS response packets (Option B) are indicative of data exfiltration because attackers often encode stolen data into DNS TXT or other record types, causing response sizes to exceed the typical 512-byte limit and triggering EDNS0 extensions. This anomaly stands out against normal DNS traffic, where most responses are small.

Sysmon Event ID 8 (CreateRemoteThread) is directly associated with code injection because it logs when a thread is created in a remote process, a common technique used by malware to inject malicious code into a legitimate process. Event ID 10 (ProcessAccess) is also critical as it records when a process opens a handle to another process, often a precursor to injecting code via APIs like OpenProcess and WriteProcessMemory.

DNS tunnelling encodes data in subdomain queries, and periodic beaconing is common for C2. High entropy subdomains and regular intervals suggest DNS tunnelling for C2.

The three-way handshake (SYN, SYN-ACK, ACK) completes a TCP connection, but the immediate RST after the ACK indicates the client terminated the connection without sending any application data. This pattern is characteristic of a port scan (e.g., using nmap's connect scan), where the scanner verifies the port is open by completing the handshake and then immediately resets to avoid leaving the connection half-open.

A false positive occurs when an alert is triggered but no actual attack exists. The file is benign, so the alert is incorrect.

Average bandwidth usage per hour is correct because it establishes a baseline of typical traffic volume over time, allowing the analyst to detect sudden spikes or drops that may indicate anomalies such as DDoS attacks or data exfiltration. Number of connections per host is correct because it provides a per-device baseline for connection counts, enabling detection of unusual behavior like port scans, botnet activity, or compromised hosts generating excessive outbound connections.

This is a phishing attack because the attacker uses a fraudulent email that impersonates a trusted entity (the IT department) to trick the recipient into clicking a malicious link and entering sensitive login credentials. Phishing is a broad category of social engineering that relies on deceptive electronic communications, typically email, to harvest credentials or deliver malware.

PCI DSS is the Payment Card Industry Data Security Standard for credit card data.

A SYN scan sends SYN packets to target ports. If a RST is received, the port is closed. The incomplete handshake is characteristic of a SYN scan, not a full connection scan or DoS attack.

Active reconnaissance involves direct interaction with the target. Port scanning and ping sweeps are active; WHOIS and Google searches are passive.

Large outbound data transfers via HTTP POST to external IPs are indicative of data exfiltration.

The correct first action is to isolate the DNS server from the network and escalate to incident response. A DNS server generating outbound DNS queries to a known malicious domain indicates a likely compromise (e.g., DNS tunneling or malware command-and-control), not normal recursive resolution. Immediate containment prevents further data exfiltration or lateral movement, aligning with incident response best practices.