CompTIA CS0-003 CySA+ Exam Dumps and Practice Test Questions Set 2 Q16-30
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Question 16
An organization has detected abnormal outbound traffic from a web server to multiple external IP addresses. The traffic occurs in short bursts every 15 minutes, mostly over TCP port 443, and the payloads appear encrypted. What is the most likely explanation, and what should the analyst prioritize first?
A) The server is performing routine SSL-based application updates; no action is required.
B) The server is part of a botnet conducting periodic command-and-control communications; investigate process memory and block IPs.
C) The server is misconfigured with an open proxy, relaying client traffic; disable proxy functionality immediately.
D) The traffic is a legitimate user data upload activity; confirm user behavior before taking action.
Answer: B)
Explanation:
A) Routine SSL-based application updates typically occur at scheduled intervals defined by the software vendor. The payloads are often larger, occur in a small set of trusted domains, and do not exhibit the regular periodic beaconing behavior described. Traffic to multiple, rotating external IP addresses with short, frequent bursts is atypical for normal updates. Assuming the traffic is benign without validation risks leaves a compromise uninvestigated.
B) The behavior closely aligns with command-and-control (C2) communication patterns observed in botnet-infected hosts or compromised servers. Attackers often use standard ports like TCP 443 to blend with normal HTTPS traffic, making detection more challenging. Encrypted payloads and beaconing at fixed intervals indicate that the server may be receiving commands or sending exfiltrated data. Investigating the memory of running processes can reveal injected code, anomalous threads, or in-memory payloads. Blocking the suspicious external IP addresses while retaining packet captures is critical for containment. Additional steps include correlating the IPs with threat intelligence databases, inspecting logs for lateral movement, and auditing for other indicators of compromise. Effective response balances containment with forensic preservation, ensuring analysts can understand attack methodology and prevent further spread.
C) A misconfigured open proxy could result in external connections, but traffic generated by legitimate users relaying generally exhibits unpredictable timing, varied destinations, and normal web browsing patterns. The periodic bursts and encrypted payloads seen here are inconsistent with standard proxy behavior. Disabling proxy functionality without confirming the cause could interrupt legitimate service operations unnecessarily.
D) Labeling the traffic as legitimate user uploads is not a prudent first step. While user-uploaded data may occasionally use HTTPS, it does not typically occur in precisely timed intervals with encrypted bursts to multiple external IPs. Accepting it as normal without verification risks overlooking potential data exfiltration or active compromise.
The priority is to determine whether the activity represents malicious communication. Memory analysis and network monitoring allow the SOC to capture evidence and understand the payloads without immediately disrupting operations. The combination of temporal patterns, encrypted communications, and external connections to multiple IPs strongly indicates C2 activity, justifying containment, investigation, and remediation measures before broader damage can occur.
Question 17
A security analyst notices an unusual increase in failed login attempts on several privileged accounts over the weekend. The attempts come from multiple geographic locations that do not align with users’ typical access patterns. What is the most appropriate initial action?
A) Lock all privileged accounts to prevent further access.
B) Analyze authentication logs and correlate failed attempts with known threat intelligence sources.
C) Notify users to change their passwords immediately and enable multifactor authentication.
D) Ignore the attempts because failed logins are common during weekends.
Answer: B)
Explanation:
A) Locking all privileged accounts could prevent potential unauthorized access, but it may also disrupt critical business operations. Account lockouts are an effective response when compromise is confirmed or imminent, but doing so without evidence could unnecessarily impact productivity.
B) Correlating authentication logs with threat intelligence provides visibility into potential attack patterns. Failed login attempts from multiple unexpected geographic locations often indicate credential-stuffing, brute force, or targeted attacks. By reviewing log timestamps, source IPs, device identifiers, and associated user behaviors, analysts can determine whether these attempts are malicious. Threat intelligence feeds can provide additional context, such as known attacker IP ranges or botnet-related sources. This methodical approach ensures that the security team makes informed decisions about containment, such as temporary IP blocking, account monitoring, or selective enforcement of multifactor authentication.
C) Notifying users to reset passwords and enabling MFA is a reactive approach that may help prevent account compromise. However, if the attack is ongoing, these actions alone may not stop the attackers from exploiting already obtained credentials. Furthermore, without analyzing the source and scope of attacks, the organization may miss identifying other affected accounts or attack vectors.
D) Ignoring failed logins during weekends is unsafe. Attackers often exploit periods of reduced monitoring to launch attacks, and failed authentication attempts are key indicators of potential compromise. Dismissing them could allow attackers to escalate privileges and gain unauthorized access.
Prioritizing log analysis and correlation ensures the security team can confirm whether the activity is malicious, determine scope, and implement targeted remediation. A structured investigation avoids unnecessary disruption while maximizing detection accuracy and preserving forensic evidence.
Question 18
During a routine security assessment, a server shows high CPU usage from a process that continuously spawns child processes and establishes outbound connections to multiple countries. The binary is signed by a legitimate vendor but was downloaded from an unofficial website. What is the best interpretation, and what action should follow?
A) The binary is safe because it is vendor-signed; approve it and monitor it.
B) The binary is likely compromised or tampered; isolate the server and perform memory and disk forensics.
C) The CPU usage is caused by legitimate vendor updates; reboot the server.
D) The server is experiencing normal heavy load; no action is required.
Answer: B)
Explanation:
A) Vendor signatures do indicate authenticity, but if a binary is obtained from an unofficial website, the signature may be fraudulent or the binary tampered with. Assuming safety solely based on signing is risky, as attackers sometimes repackage signed software or exploit stolen keys to distribute malware. Approving it without further investigation could result in ongoing compromise.
B) The observed high CPU usage, repeated spawning of child processes, and outbound connections to multiple countries strongly suggest malicious behavior. Supply-chain attacks or binary tampering can replace legitimate software with malware, often leveraging trusted binaries to bypass endpoint protection. The correct action is to isolate the server from the network to prevent lateral movement or data exfiltration, then perform detailed memory and disk forensics. Memory analysis captures volatile data such as injected code or runtime payloads, while disk forensics ensures the collection of binaries, logs, and configuration files. Together, these steps allow analysts to verify compromise, determine scope, and remediate appropriately.
C) Assuming CPU spikes are caused by vendor updates without verification is unsafe. Legitimate updates usually follow predictable patterns and do not create multiple child processes with unusual outbound communication. Rebooting may temporarily alleviate the load, but it does not address potential malware.
D) Treating the server as a normal high load disregards multiple indicators of compromise. Ignoring the activity may allow attackers to persist, escalate privileges, or exfiltrate data.
Prioritizing investigation and forensic analysis ensures that potentially compromised servers are handled correctly while preserving evidence. Once the investigation confirms tampering, further actions include revoking compromised binaries, updating policies for trusted sources, and enhancing detection signatures for future incidents.
Question 19
A SOC team observes multiple endpoints sending unusual SMB traffic to a rarely accessed internal file share outside regular business hours. Some connections are reading small portions of multiple files, and others attempt unauthorized writes. What is the likely security concern?
A) Normal off-hours backup activity; no action required.
B) Internal reconnaissance or lateral movement by malware; investigate logs and isolate affected hosts.
C) Misconfigured scheduled tasks accessing file shares; correct task configurations.
D) Users performing legitimate remote access operations; notify users to verify activity.
Answer: B)
Explanation:
A) Normal backup activity is typically scheduled, consistent, and documented. Backup processes generally read or write entire files or directories, rather than small portions of multiple files in an irregular pattern. Assuming these activities are backups risks missing malicious activity.
B) Small, targeted SMB reads and unauthorized write attempts outside business hours often indicate malware performing internal reconnaissance or lateral movement. Malware may probe for sensitive files, enumerate accessible directories, or prepare for data exfiltration. Investigating system and file share logs allows identification of which hosts are involved, timeframes, and specific files accessed. Isolation of affected endpoints prevents further spread while enabling forensic analysis to determine infection vector and remediation steps. Detecting lateral movement early is critical for limiting the scope of compromise.
C) Misconfigured scheduled tasks could generate file share traffic, but these tasks are usually predictable and documented. Patterns of repeated unauthorized access and irregular small file reads suggest deliberate exploration rather than accidental misconfiguration.
D) Legitimate remote access is typically tied to authorized accounts, occurs during expected hours, and follows standard operational patterns. Treating unusual off-hour SMB traffic as legitimate user activity could allow malware to persist undetected.
Proper investigation involves correlating network logs, endpoint telemetry, and access records to confirm whether activity is malicious, followed by containment, remediation, and policy updates to prevent future incidents.
Question 20
During a threat hunting exercise, analysts discover a Linux server making repeated ICMP requests with unusually large payloads to external hosts. The traffic is low-volume but persistent. What is the most probable purpose of this activity, and what is the immediate response?
A) Normal network diagnostic activity; ignore.
B) Covert data exfiltration using ICMP tunnels; capture traffic and analyze payloads.
C) Ping floods from the server; throttle ICMP traffic to mitigate risk.
D) Misconfigured monitoring software; update configurations.
Answer: B)
Explanation:
A) Routine network diagnostics use ICMP for ping and traceroute, but large and persistent payloads to external hosts, especially in low volume, are atypical for normal network checks. Ignoring this activity may allow covert exfiltration or persistent C2 channels to continue.
B) ICMP tunnels are a known method for covert communication and data exfiltration. Attackers use ICMP because it is often allowed through firewalls and can evade standard monitoring. The persistent, low-volume but large payload traffic suggests data is being encoded and sent to external destinations. The immediate response should be to capture the traffic for analysis, determine the source process, and decode any embedded data. This preserves evidence and helps identify the scope of compromise. Following analysis, containment measures may include blocking outbound ICMP to untrusted destinations, isolating the server, and reviewing endpoint security for malware or unauthorized tunneling software.
C) Ping floods are denial-of-service attacks typically generating high-volume traffic to overwhelm targets. The observed low-volume ICMP traffic is inconsistent with a flood attack, so throttling alone would not address the potential covert channel or identify the underlying compromise.
D) Misconfigured monitoring software could generate ICMP traffic, but persistent, targeted external communication with large payloads is not characteristic of standard monitoring tools. Updating configurations without investigation could miss malicious activity.
Proper investigation involves correlating endpoint telemetry, network logs, and host processes to determine whether the ICMP traffic is benign or malicious, then taking steps to contain, remediate, and document the incident for future threat hunting and preventive measures.
Question 21
A security analyst detects that a workstation is making repeated HTTPS connections to a domain that was recently registered and has no associated reputation. The connections occur at regular 10-minute intervals, and packet analysis shows small, encoded payloads. What is the most likely cause of this activity, and what should be the immediate response?
A) The workstation is downloading routine application updates; allow connections.
B) The workstation is communicating with a command-and-control server using HTTPS covert channels; capture traffic and isolate the host.
C) The connections are caused by scheduled cloud backups; verify configuration with the user.
D) The workstation is scanning for open ports externally; block outbound scanning.
Answer: B)
Explanation:
A) Routine application updates over HTTPS are typically performed to trusted domains with well-known certificates and predictable update patterns. Newly registered domains with no reputation, and the small, encoded payloads do not match normal update behavior. Allowing these connections could allow malicious activity to continue unnoticed.
B) The repeated, small, encoded HTTPS connections to a recently registered domain strongly indicate command-and-control (C2) activity. Malware often uses newly created domains to avoid detection and frequently employs HTTPS to blend in with legitimate traffic. The periodic pattern is characteristic of beaconing, where compromised hosts check in with a remote server to receive instructions or exfiltrate data. Immediate response should include capturing network traffic for forensic analysis, isolating the compromised host to prevent lateral movement or data exfiltration, and cross-referencing the domain with threat intelligence sources. Subsequent actions may include analyzing the host for malware persistence mechanisms, checking logs for other affected systems, and updating intrusion detection or prevention rules to block the malicious domain.
C) Scheduled cloud backups can generate periodic network traffic, but they generally use trusted domains and documented endpoints, not newly registered unknown domains. Payloads are usually larger and reflect complete file transfers rather than small encoded fragments. Assuming the traffic is benign, backup activity could fail to detect a compromise.
D) Outbound port scanning produces a different pattern—usually multiple destinations or ports rather than repeated small HTTPS POSTs to the same domain. While scanning could be suspicious, the description aligns more closely with a C2 covert channel than network reconnaissance.
The correct approach prioritizes identifying the malicious communication, isolating the host, and preserving evidence while mitigating further compromise. This ensures that any malware or C2 infrastructure can be analyzed, remediated, and prevented from impacting other systems.
Question 22
An intrusion detection system generates an alert for repeated SQL injection attempts against a web application. The requests contain unusual payloads with encoded characters and nested queries. What is the recommended next step for the security analyst?
A) Block all incoming traffic to the web application immediately.
B) Review the web server logs and analyze the injection attempts for pattern recognition.
C) Rebuild the web server from a clean image.
D) Notify users to change their database passwords immediately.
Answer: B)
Explanation:
A) Blocking all traffic to the web application immediately may stop malicious activity, but it also interrupts legitimate operations, potentially causing downtime for users. Immediate full blocking should only occur if the risk of exploitation is critical and ongoing.
B) Reviewing web server logs and analyzing injection attempts is the correct next step. Logs contain detailed request information, including payload content, source IP addresses, and timing, which allows the analyst to identify attack patterns and determine the potential scope of exploitation. Encoded and nested SQL payloads indicate that attackers are attempting to bypass input validation or web application firewall protections. By analyzing these attempts, the analyst can identify vulnerabilities, correlate activity with known attack signatures, and create targeted mitigation strategies. Actions following analysis may include updating WAF rules, patching the application, or implementing input sanitization measures to prevent future attacks. This method preserves business continuity while addressing the security threat efficiently.
C) Rebuilding the web server is a drastic measure and is unnecessary unless there is evidence that the server has been compromised or defaced. While rebuilding ensures a clean environment, it does not address the root cause if the web application remains vulnerable.
D) Notifying users to change database passwords without confirming whether the SQL injection attempts succeeded is premature. If the database has not been compromised, password changes are unnecessary and may distract from remediation of the actual vulnerability.
Focusing on log review and analysis allows the security team to understand the attack method, verify whether exploitation occurred, and implement precise defenses, minimizing disruption while enhancing security posture.
Question 23
A security operations center notices unusual traffic from several workstations to an external IP over UDP port 53. Analysis shows DNS queries with extremely long subdomain names, and the responses appear encoded. What is the likely security concern, and what should be done first?
A) Normal DNS activity; no action needed.
B) DNS tunneling used for covert exfiltration; monitor traffic and capture payloads.
C) Misconfigured internal DNS resolver; fix DNS configuration.
D) Routine antivirus updates using DNS; verify update server IPs.
Answer: B)
Explanation:
A) Standard DNS queries usually consist of short domain names and are resolved quickly. Extremely long subdomains and encoded responses are inconsistent with normal DNS activity and often indicate covert channels. Ignoring this behavior risks missing exfiltration or malware communication.
B) DNS tunneling is a technique used to transmit data covertly over DNS queries and responses. Attackers encode data in subdomain requests and extract it from DNS server responses. The signs here—multiple workstations, long subdomain names, and encoded responses—strongly suggest exfiltration attempts. The immediate response should be to capture and analyze the traffic, decode the data, and identify affected endpoints. Network monitoring and containment steps, such as blocking communication to the suspicious external IP, can help prevent further data loss. Additional follow-up includes reviewing DNS logs for historical activity, validating endpoint integrity, and enhancing detection rules for DNS tunneling.
C) Misconfigured DNS resolvers generally result in failed lookups or incorrect resolution, but do not typically generate encoded payloads or persistent traffic patterns that appear malicious. Fixing DNS without analysis might disrupt ongoing investigation or fail to detect active data exfiltration.
D) Antivirus updates rarely use DNS for payload delivery; update mechanisms generally rely on HTTP/HTTPS and known update servers. Assuming DNS traffic is legitimate without analysis risks overlooking potential compromise.
DNS tunneling requires careful monitoring and analysis to confirm malicious activity while preserving evidence for incident response. Detecting it early allows analysts to mitigate risks without interrupting normal business operations unnecessarily.
Question 24
An analyst identifies a workstation executing a new PowerShell script that downloads a file from a URL not associated with any corporate vendor. The script is obfuscated and runs in memory without writing files to disk. What type of threat does this indicate, and what is the recommended response?
A) Legitimate administrative automation allows execution.
B) Fileless malware using PowerShell to execute payloads in memory; isolate the host and perform memory analysis.
C) Routine software installation; monitor for completion.
D) Misconfigured endpoint configuration management script; update script repository.
Answer: B)
Explanation:
A) Legitimate administrative scripts usually come from known sources, are signed, and are reviewed before execution. Allowing unknown, obfuscated scripts to run can result in compromise.
B) The behavior described—obfuscated PowerShell, downloading from an untrusted URL, and executing entirely in memory—is a hallmark of fileless malware. Fileless attacks avoid writing to disk to evade antivirus detection and persist by using legitimate system processes. Isolating the host prevents lateral movement or further exploitation, while memory analysis allows forensic investigators to capture the in-memory payload, analyze the code, and identify the threat actor’s methods. Additional steps include blocking the URL at network perimeter controls, scanning other endpoints for similar activity, and updating detection rules to catch future fileless attacks.
C) Routine software installations are generally signed, documented, and do not employ obfuscation or memory-only execution. Assuming this behavior is normal could result in widespread compromise.
D) Misconfigured management scripts could execute unexpectedly, but the obfuscation, external download, and memory-only execution indicate malicious intent rather than a configuration error. Updating the script repository without investigation ignores the threat.
Identifying fileless malware quickly is crucial to preventing persistent infection. Isolation, memory capture, and forensic analysis provide evidence for remediation and improvement of detection capabilities.
Question 25
During a SOC investigation, analysts observe a spike in failed SSH login attempts from several external IP addresses to multiple Linux servers. Attempts are coming from a wide geographic range, and usernames correspond to known privileged accounts. What is the most appropriate immediate action?
A) Ignore the attempts because failed logins are common.
B) Block the attacking IP addresses, enable rate-limiting, and review logs for successful compromises.
C) Disable SSH across all servers temporarily.
D) Notify users to change their passwords without further investigation.
Answer: B)
Explanation:
A) Ignoring failed SSH logins, particularly those targeting privileged accounts from multiple geolocations, is dangerous. Attackers often perform brute-force or credential-stuffing attacks to gain unauthorized access. Dismissing these alerts could allow a successful compromise.
B) Blocking the source IPs and enabling rate-limiting on SSH connections helps contain ongoing brute-force attempts while preventing excessive disruption to legitimate users. Reviewing logs for any successful authentication ensures detection of compromised accounts. Implementing multi-factor authentication strengthens security for privileged accounts. Additionally, analyzing IP addresses with threat intelligence can identify botnet or attacker infrastructure. These steps collectively protect critical systems while preserving forensic evidence for further analysis.
C) Disabling SSH on all servers is a disruptive measure that could halt legitimate administrative operations. This extreme response is only appropriate if compromise is confirmed and immediate containment is necessary.
D) Notifying users to change passwords without investigating whether their accounts were actually targeted or compromised may result in unnecessary operational overhead. Investigation should precede notification and remediation to ensure actions are appropriate.
Proper response requires containment, verification, and mitigation. Blocking attacker IPs, limiting authentication attempts, and monitoring for successful access ensure protection of servers while informing longer-term security measures.
Question 26
A security analyst notices that several endpoints are communicating with a domain that is categorized as “dynamic DNS” and has been associated with past malware campaigns. The traffic is low-volume but persistent and occurs at random intervals throughout the day. What is the most likely explanation, and what is the immediate response?
A) The endpoints are performing legitimate cloud service operations; ignore the traffic.
B) The endpoints are infected and using a dynamic DNS-based command-and-control channel; isolate hosts and capture network traffic.
C) Dynamic DNS services are required for VPN connectivity; allow connections.
D) Users are testing external services using dynamic DNS; notify users to stop.
Answer: B)
Explanation:
A) While some legitimate services may use dynamic DNS, the combination of low-volume but persistent traffic, random intervals, and association with malware campaigns suggests anomalous behavior rather than normal cloud service activity. Ignoring this traffic could allow attackers to maintain a covert channel or exfiltrate data undetected.
B) Dynamic DNS is frequently exploited by attackers to maintain command-and-control (C2) infrastructure, allowing malware to communicate with external servers without a fixed IP. Low-volume and intermittent communications are characteristic of beaconing behavior designed to evade detection while maintaining persistent access. The immediate response should be to isolate affected endpoints to prevent lateral movement and contain potential exfiltration. Capturing network traffic provides forensic evidence to analyze payload content, identify the malware family, and determine the attack scope. Following analysis, security teams can block malicious domains at the DNS or firewall level, update detection rules for similar activity, and ensure endpoints are fully remediated. This response prioritizes both containment and investigation, minimizing operational disruption while addressing the threat effectively.
C) VPN connectivity sometimes leverages dynamic DNS services for client connections; however, legitimate VPN traffic generally uses known endpoints, authentication credentials, and secure channels. Random intervals and association with past malware campaigns make this explanation less likely. Allowing the traffic without validation risks persistent compromise.
D) Users testing external dynamic DNS services is plausible but typically occurs from a small subset of endpoints, not several simultaneously, and is usually associated with known user activity. Assuming user testing as the cause without verification could lead to ignoring malicious behavior.
This scenario demonstrates the importance of correlating traffic patterns, threat intelligence, and endpoint behavior to identify covert channels and take informed containment actions.
Question 27
During a routine review of SIEM alerts, analysts notice repeated alerts for PowerShell command execution on a server that is not typically used for administrative tasks. The commands are obfuscated, and the server has initiated connections to multiple external hosts. What is the most likely cause of this behavior, and what should the SOC do first?
A) The server is performing routine administrative tasks; continue monitoring.
B) Malicious scripts have been executed via PowerShell, potentially indicating a fileless malware infection; isolate the host and perform memory analysis.
C) Scheduled updates are being applied via PowerShell; verify the update process.
D) Remote troubleshooting is being performed by IT staff; notify staff and approve activity.
Answer: B)
Explanation:
A) Routine administrative tasks on a server not designated for management functions are unusual. Legitimate activities rarely involve obfuscated PowerShell scripts, connections to multiple external hosts, or unexpected command execution. Assuming normal operation risks, ignoring malicious behavior.
B) Fileless malware often leverages PowerShell to execute payloads directly in memory, avoiding disk-based detection. Indicators include obfuscated scripts, unexpected execution on non-administrative servers, and outbound connections to external hosts. The immediate response should be to isolate the host to prevent lateral movement or exfiltration while retaining forensic evidence. Memory analysis is critical for capturing the in-memory payload, identifying persistence mechanisms, and understanding the attacker’s objectives. Additional measures include analyzing logs for lateral movement, cross-referencing IPs with threat intelligence, and applying endpoint detection rules to prevent similar attacks. This approach allows containment without disrupting other systems and ensures detailed evidence collection for remediation and reporting.
C) Scheduled updates via PowerShell are typically documented, signed, and predictable. The unexpected obfuscation, server role, and external communications indicate a higher likelihood of compromise than routine updates. Verifying updates alone does not address the potential threat.
D) Remote troubleshooting by IT staff is usually controlled, authorized, and documented. Assuming that obfuscated PowerShell scripts on an unusual server represent legitimate activity would ignore potential malicious behavior and compromise the integrity of the network.
Prioritizing host isolation, memory analysis, and threat intelligence correlation ensures detection, containment, and proper remediation of fileless malware threats.
Question 28
A SOC analyst observes that several endpoints are sending small chunks of data over HTTP to a public cloud service at irregular intervals. The domains being contacted are not recognized by IT, and some data appears to be encoded. What is the likely concern, and what is the recommended response?
A) Legitimate SaaS usage; allow traffic.
B) Potential data exfiltration via HTTP to a cloud service; capture traffic, isolate endpoints, and analyze payloads.
C) Normal antivirus updates using HTTP; verify the update server IPs.
D) Internal web application testing; inform users to cease testing.
Answer: B)
Explanation:
A) Legitimate SaaS usage is typically predictable, uses known domains, and is associated with specific user accounts. Low-volume, irregular, and encoded traffic to unknown domains is inconsistent with normal operations. Allowing it risks ongoing data exfiltration.
B) Data exfiltration over HTTP is a common tactic used by attackers to avoid detection. Small, irregular chunks suggest attempts to bypass monitoring thresholds while transmitting information from endpoints. Capturing traffic allows analysts to reconstruct and decode the data, understand the type of sensitive information at risk, and identify malware or scripts responsible. Isolating affected endpoints prevents further data leakage while preserving evidence. Follow-up actions include blocking malicious domains, investigating the infection vector, and performing endpoint remediation. This approach balances containment with detailed investigation, ensuring protection against ongoing threats while minimizing operational disruption.
C) Antivirus updates rarely transmit small, encoded HTTP chunks; update traffic usually involves direct downloads from known vendor domains. Assuming normal updates could overlook malicious activity.
D) Internal web application testing may generate some HTTP traffic, but encoded payloads and unrecognized domains point toward malicious exfiltration rather than testing. Notifying users without investigation does not mitigate the risk.
Proper investigation involves correlating network patterns, payload analysis, and endpoint telemetry to confirm exfiltration and remediate affected systems.
Question 29
During vulnerability scanning, several Linux servers report an outdated SSH implementation with known privilege escalation CVEs. Patch management indicates all updates were applied last month. What is the best approach to verify this finding?
A) Ignore the scanner output because patches were applied.
B) Cross-check the SSH version and configuration on the servers, review vendor advisories, and test exploitability in a controlled environment.
C) Reinstall all Linux servers from scratch to ensure security.
D) Disable SSH on all servers until the scanner confirms no vulnerabilities.
Answer: B)
Explanation:
A) Ignoring the scanner output risks missing a genuine vulnerability. Vulnerability scanners may misreport due to configuration differences, missing patches, or misinterpretation of system responses. Relying solely on patch management without validation could leave servers exposed.
B) Verification involves checking the actual SSH version and server configuration to confirm whether known vulnerabilities exist. Reviewing vendor advisories ensures patches were applied correctly and completely. Testing exploitability in a controlled lab environment can determine whether the reported CVEs can be leveraged in the current server configuration. This thorough approach prevents unnecessary downtime while accurately assessing risk. If a vulnerability exists, remediation can be applied in a targeted manner, reducing operational disruption and ensuring compliance.
C)Reinstalling servers is a drastic measure that should be approached with caution, as it carries significant operational and logistical implications. While it can provide a clean slate, removing all potential vulnerabilities and misconfigurations, it is inherently disruptive to business continuity, often requiring substantial downtime, restoration of data from backups, and reconfiguration of applications and services. In most cases, vulnerabilities can be effectively addressed through less invasive methods such as configuration adjustments, security hardening, or targeted patching. For instance, applying security patches to software components, updating system libraries, or modifying configuration files to close exposure points can remediate specific issues without necessitating a full system rebuild. These actions are generally faster, minimize disruption to users and dependent systems, and allow IT teams to maintain service availability while still improving security posture. Additionally, reinstalling a server may not always eliminate risks, particularly if the underlying processes, credentials, or network configurations that contributed to the vulnerability are preserved or mismanaged during reinstallation. It is also important to consider that a full server reinstall involves restoring backups, which could inadvertently reintroduce vulnerabilities if the backups contain compromised data or outdated software versions. Therefore, careful verification of the vulnerability, coupled with targeted remediation, is both a more efficient and safer approach in most scenarios. Targeted patching also allows organizations to address the specific threat without overhauling entire systems, reducing the risk of operational errors or misconfigurations that can occur during a full rebuild. For example, if a vulnerability is identified in a web application server, applying the latest security patches, updating dependent frameworks, and adjusting relevant security settings can often eliminate the issue while leaving other critical services intact. This approach also provides a clear audit trail, demonstrating that the vulnerability was assessed, tested, and remediated in a controlled manner, which is important for regulatory compliance and internal governance. Reinstallation should be reserved for situations where a system is irreparably compromised, such as in the case of widespread malware infection, persistent rootkits, or deeply embedded configuration corruption that cannot be reliably corrected through conventional remediation. Even then, careful planning is required to ensure that data integrity, user access, and system functionality are preserved during the process. By prioritizing verification and targeted remediation over wholesale reinstallation, organizations can maintain a balance between security and operational efficiency, ensuring that vulnerabilities are addressed in a controlled, effective, and minimally disruptive manner. This approach fosters better long-term security practices, as IT teams develop a deeper understanding of system configurations, threat landscapes, and appropriate mitigation strategies, rather than relying on complete system replacement as a default response. Ultimately, reinstalling servers is a tool for extreme cases rather than a routine solution, and judicious use ensures resources are applied where they are most needed, avoiding unnecessary downtime while still maintaining a strong security posture.
D)Disabling SSH on all servers is an extreme measure that can severely disrupt administrative operations, preventing system updates, troubleshooting, and essential maintenance. Such a blanket action is disproportionate to most security concerns, as it halts legitimate access while offering little targeted mitigation. A more effective approach is targeted verification, where servers are individually assessed for vulnerabilities or compromise. This allows administrators to apply precise fixes, adjust configurations, or implement access controls without interrupting critical system management. By addressing the actual risk rather than implementing broad restrictions, organizations maintain both security and operational continuity.
Effective verification involves systematically assessing systems to confirm the existence, scope, and severity of vulnerabilities. This process ensures that security teams focus on real threats rather than hypothetical or false-positive issues, enabling accurate prioritization of remediation efforts based on risk. By identifying which systems and components are truly at risk, organizations can apply targeted fixes, patches, or configuration changes without unnecessary disruption. This approach reduces downtime, preserves business operations, and optimizes resource allocation. Ultimately, effective verification balances security needs with operational continuity, ensuring that vulnerabilities are addressed efficiently while minimizing negative impact on business functions and productivity.
Question 30
A SOC analyst observes an endpoint executing a scheduled task that invokes a script connecting to multiple external IPs using custom TCP ports. The script logs have been cleared, and the endpoint has been rebooted several times recently. What is the most likely scenario, and what is the recommended action?
A) Routine maintenance task; allow execution.
B) Persistent malware using scheduled tasks for C2 communication; isolate the endpoint, perform memory and disk forensics, and identify persistence mechanisms.
C) Misconfigured administrative script; update the script repository.
D) Endpoint misbehavior due to reboot; monitor the endpoint.
Answer: B)
Explanation:
A) Routine maintenance tasks rarely involve multiple external connections to unknown IPs over custom TCP ports. Assuming it is normal without analysis could leave a compromise unaddressed.
B) The observed pattern—scheduled task execution, external communication on nonstandard ports, cleared logs, and repeated reboots—is consistent with persistent malware attempting to maintain command-and-control access. The recommended response is to isolate the endpoint to prevent further compromise, perform memory and disk forensics to capture in-memory payloads and persistent artifacts, and identify how the malware maintains persistence. Additional steps include blocking the malicious IPs, reviewing similar endpoints for compromise, and applying detection rules to prevent recurrence. Documenting the incident ensures lessons learned and improvement of incident response processes.
C)Misconfigured scripts in a system often produce symptoms that are relatively easy to identify and are typically limited to error messages, failed processes, or predictable patterns of unusual traffic. For instance, a script with a syntax error or incorrect parameters may repeatedly fail to execute, triggering error logs that can alert administrators to the underlying issue. Similarly, scripts that inadvertently generate excessive or abnormal traffic usually do so in a manner that follows recognizable patterns, allowing for detection and resolution through routine debugging or monitoring. In contrast, the presence of cleared logs, unusual external connections, or obfuscated persistence mechanisms is rarely a product of simple misconfiguration. Such behaviors are more indicative of deliberate, malicious activity, as attackers often take deliberate steps to hide their presence, maintain long-term access, and exfiltrate data without detection. Attempting to correct scripts without a thorough investigation in this context could result in a significant oversight, as the apparent errors may actually mask a more sophisticated intrusion or compromise. Misinterpreting these indicators as benign script errors could allow an attacker to continue operating undetected, potentially causing greater harm to the system and the broader network environment.
D)Endpoint reboots, while sometimes a symptom of ordinary issues such as system instability, software updates, or hardware failures, acquire a different significance when observed alongside unusual external communications and evidence of log tampering. In such a scenario, the combination of multiple unusual behaviors suggests deliberate interference rather than random misbehavior. For example, an attacker may trigger a reboot to disrupt monitoring, bypass security controls, or apply changes to the system that require a restart, all while maintaining covert connections to external systems. The deliberate clearing of logs further emphasizes intent, as it is a common tactic used to eliminate traces of unauthorized activity and hinder forensic investigation. The presence of obfuscated persistence mechanisms, such as hidden processes, disguised scheduled tasks, or encrypted scripts, reinforces the conclusion that the activity is malicious, as these measures are designed to evade detection and maintain control over the system. Taken together, these factors create a pattern that distinguishes intentional attacks from ordinary system misconfigurations. Understanding the difference is crucial for effective incident response, as treating malicious behavior as a routine script error could delay detection, allow for further compromise, and reduce the ability to mitigate risks promptly. A careful and comprehensive investigation that considers all symptoms, including endpoint behavior, network traffic, and log integrity, is essential to accurately identify the root cause and implement appropriate countermeasures. This approach ensures that both the immediate threat is addressed and long-term security is reinforced, preventing recurrence and protecting sensitive assets from further exploitation.
Prioritizing containment, evidence preservation, and forensic analysis ensures accurate detection and remediation of persistent malware while preventing further network impact.