CompTIA Security+ Question K-85

Four weeks ago, a network administrator applied a new IDS and allowed it to gather baseline data. As rumors of a layoff began to spread, the IDS alerted the network administrator that access to sensitive client files had risen far above normal. Which of the following kind of IDS is in use?

A. Protocol based
B. Heuristic based
C. Signature based
D. Anomaly based

Answer: D

Explanation:
Most intrusion detection systems (IDS) are what is known as signature-based. This means that they operate in much the same way as a virus scanner, by searching for a known identity – or signature – for each specific intrusion event. And, while signature-based IDS is very efficient at sniffing out known methods of attack, it does, like anti-virus software, depend on receiving regular signature updates, to keep in touch with variations in hacker technique. In other words, signature-based IDS is only as good as its database of stored signatures. Any organization wanting to implement a more thorough – and hence safer – solution, should consider what we call anomaly-based IDS. By its nature, anomaly-based IDS is a rather more complex creature. In network traffic terms, it captures all the headers of the IP packets running towards the network. From this, it filters out all known and legal traffic, including web traffic to the organization’s web server, mail traffic to and from its mail server, outgoing web traffic from company employees and DNS traffic to and from its DNS server.

There are other equally obvious advantages to using anomaly-based IDS. For example, because it detects any traffic that is new or unusual, the anomaly method is particularly good at identifying sweeps and probes towards network hardware. It can, therefore, give early warnings of potential intrusions, because probes and scans are the predecessors of all attacks. And this applies equally to any new service installed on any item of hardware – for example, Telnet deployed on a network router for maintenance purposes and forgotten about when the maintenance was finished. This makes anomaly-based IDS perfect for detecting anything from port anomalies and web anomalies to mis-formed attacks, where the URL is deliberately mis-typed.

CompTIA Security+ Question H-82

Suspicious traffic without a specific signature was detected. Under further investigation, it was determined that these were false indicators. Which of the following security devices needs to be configured to disable future false alarms?

A. Signature based IPS
B. Signature based IDS
C. Application based IPS
D. Anomaly based IDS

Answer: D

Explanation:
Most intrusion detection systems (IDS) are what is known as signature-based. This means that they operate in much the same way as a virus scanner, by searching for a known identity – or signature – for each specific intrusion event. And, while signature-based IDS is very efficient at sniffing out known s of attack, it does, like anti-virus software, depend on receiving regular signature updates, to keep in touch with variations in hacker technique. In other words, signature-based IDS is only as good as its database of stored signatures. Any organization wanting to implement a more thorough – and hence safer – solution, should consider what we call anomaly-based IDS. By its nature, anomaly-based IDS is a rather more complex creature. In network traffic terms, it captures all the headers of the IP packets running towards the network. From this, it filters out all known and legal traffic, including web traffic to the organization’s web server, mail traffic to and from its mail server, outgoing web traffic from company employees and DNS traffic to and from its DNS server.

There are other equally obvious advantages to using anomaly-based IDS. For example, because it detects any traffic that is new or unusual, the anomaly method is particularly good at identifying sweeps and probes towards network hardware. It can, therefore, give early warnings of potential intrusions, because probes and scans are the predecessors of all attacks. And this applies equally to any new service installed on any item of hardware – for example, Telnet deployed on a network router for maintenance purposes and forgotten about when the maintenance was finished. This makes anomaly-based IDS perfect for detecting anything from port anomalies and web anomalies to mis-formed attacks, where the URL is deliberately mis-typed.

CompTIA Security+ Question H-53

The security administrator is observing unusual network behavior from a workstation. The workstation is communicating with a known malicious destination over an encrypted tunnel. A full antivirus scan, with an updated antivirus definition file, does not show any signs of infection.
Which of the following has happened on the workstation?

A. Zero-day attack
B. Known malware infection
C. Session hijacking
D. Cookie stealing

Answer: A

Explanation:
The vulnerability was unknown in that the full antivirus scan did not detect it. This is zero day vulnerability. A zero day vulnerability refers to a hole in software that is unknown to the vendor. This security hole is then exploited by hackers before the vendor becomes aware and hurries to fix it—this exploit is called a zero day attack. Uses of zero day attacks can include infiltrating malware, spyware or allowing unwanted access to user information. The term “zero day” refers to the unknown nature of the hole to those outside of the hackers, specifically, the developers. Once the vulnerability becomes known, a race begins for the developer, who must protect users.

CompTIA Security+ Question H-39

A server dedicated to the storage and processing of sensitive information was compromised with a rootkit and sensitive data was extracted. Which of the following incident response procedures is best suited to restore the server?

A. Wipe the storage, reinstall the OS from original media and restore the data from the last known good backup.
B. Keep the data partition, restore the OS from the most current backup and run a full system antivirus scan.
C. Format the storage and reinstall both the OS and the data from the most current backup.
D. Erase the storage, reinstall the OS from most current backup and only restore the data that was not compromised.

Answer: A

Explanation:
Rootkits are software programs that have the ability to hide certain things from the operating system. With a rootkit, there may be a number of processes running on a system that do not show up in Task Manager or connections established or available that do not appear in a netstat display—the rootkit masks the presence of these items. The rootkit is able to do this by manipulating function calls to the operating system and filtering out information that would normally appear. Theoretically, rootkits could hide anywhere that there is enough memory to reside: video cards, PCI cards, and the like. The best way to handle this situation is to wipe the server and reinstall the operating system with the original installation disks and then restore the extracted data from your last known good backup. This way you can eradicate the rootkit and restore the data.

CompTIA Security+ Question H-19

Peter a company’s new security specialist is assigned a role to conduct monthly vulnerability scans across the network. He notices that the scanner is returning a large amount of false positives or failed audits. Which of the following should Peter recommend to remediate these issues?

A. Ensure the vulnerability scanner is located in a segmented VLAN that has access to the company’s servers
B. Ensure the vulnerability scanner is configured to authenticate with a privileged account
C. Ensure the vulnerability scanner is attempting to exploit the weaknesses it discovers
D. Ensure the vulnerability scanner is conducting antivirus scanning

Answer: A

Explanation:
The vulnerability scanner is returning false positives because it is trying to scan servers that it doesn’t have access to; for example, servers on the Internet. We need to ensure that the local network servers only are scanned. We can do this by locating the vulnerability scanner in a segmented VLAN that has access to the company’s servers.

A false positive is an error in some evaluation process in which a condition tested for is mistakenly found to have been detected. In spam filters, for example, a false positive is a legitimate message mistakenly marked as UBE -­unsolicited bulk email, as junk email is more formally known. Messages that are determined to be spam — whether correctly or incorrectly — may be rejected by a server or client-side spam filter and returned to the sender as bounce e-mail. One problem with many spam filtering tools is that if they are configured stringently enough to be effective, there is a fairly high chance of getting false positives. The risk of accidentally blocking an important message has been enough to deter many companies from implementing any anti-spam measures at all. False positives are also common in security systems. A host intrusion prevention system (HIPS), for example, looks for anomalies, such as deviations in bandwidth, protocols and ports. When activity varies outside of an acceptable range – for example, a remote application attempting to open a normally closed port — an intrusion may be in progress. However, an anomaly, such as a sudden spike in bandwidth use, does not guarantee an actual attack, so this approach amounts to an educated guess and the chance for false positives can be high. False positives contrast with false negatives, which are results indicating mistakenly that some condition tested for is absent.

CompTIA Security+ Question B-17

An administrator is concerned that a company’s web server has not been patched. Which of the following would be the BEST assessment for the administrator to perform?

A. Vulnerability scan
B. Risk assessment
C. Virus scan
D. Network sniffer

Answer: A

Explanation:
A vulnerability scan is the process of scanning the network and/or I.T. infrastructure for threats and vulnerabilities. Vulnerabilities include computer systems that do not have the latest security patches installed. The threats and vulnerabilities are then evaluated in a risk assessment and the necessary actions taken to resolve and vulnerabilities. A vulnerability scan is the automated process of proactively identifying security vulnerabilities of computing systems in a network in order to determine if and where a system can be exploited and/or threatened. While public servers are important for communication and data transfer over the Internet, they open the door to potential security breaches by threat agents, such as malicious hackers. Vulnerability scanning employs software that seeks out security flaws based on a database of known flaws, testing systems for the occurrence of these flaws and generating a report of the findings that an individual or an enterprise can use to tighten the network’s security. Vulnerability scanning typically refers to the scanning of systems that are connected to the Internet but can also refer to system audits on internal networks that are not connected to the Internet in order to assess the threat of rogue software or malicious employees in an enterprise.

CompTIA A+ 220-902 Question J-85

A user has downloaded and installed a browser add-on that causes the browser to hang. The PC has very slow system response when rebooted. Which of the following should a technician do to troubleshoot this problem?

A. Run System Restore, update antivirus program, and run an antivirus scan.
B. Remove all Internet temporary files, run an antivirus scan, and reboot using Last Known Good Configuration.
C. Remove all temporary files, turn off System Restore, update and run an antivirus scan.
D. Run an antivirus scan, Run Disk Cleanup, and reboot into Safe Mode.

Correct Answer: C

Explanation:
This might be the sign of a virus infecting the system. First, remove all temporary Internet files on your computer. Viruses are downloaded through software or a webpage. And normally it resides in Temporary Internet Files folder. Now turn off system restore because you don’t want to load a previous state on the computer with the virus still lingering the digital wild. Run an antivirus program to clean infected files.

CompTIA A+ 220-902 Question F-18

A technician is about to put a computer back into service that has not been turned on for many months. It was healthy when taken out of service and boots quickly without any problems. Which of the following actions would be a best practice to begin computer maintenance? (Select TWO).

A. Run a full antivirus scan.
B. Defragment the hard disk.
C. Run antivirus updates.
D. Run Windows updates.
E. Configure the firewall to access the Internet.

Correct Answer: CD

Explanation:
You have to update the system. Run antivirus updates because antivirus changes frequently as new viruses are discovered. Run Windows updates to keep the system updated and ready to use.