A new mobile banking application is being developed and uses SSL / TLS certificates but penetration tests show that it is still vulnerable to man-in-the-middle attacks, such as DNS hijacking. Which of the following would mitigate this attack?
A. Certificate revocation B. Key escrow C. Public key infrastructure D. Certificate pinning
An administrator is investigating a system that may potentially be compromised, and sees the following log entries on the router. *Jul 15 14:47:29.779:%Router1: list 101 permitted tcp 192.10.3.204(57222) (FastEthernet 0/3) -> 10.10.1.5 (6667), 3 packets. *Jul 15 14:47:38.779:%Router1: list 101 permitted tcp 192.10.3.204(57222) (FastEthernet 0/3) -> 10.10.1.5 (6667), 6 packets. *Jul 15 14:47:45.779:%Router1: list 101 permitted tcp 192.10.3.204(57222) (FastEthernet 0/3) -> 10.10.1.5 (6667), 8 packets. Which of the following BEST describes the compromised system?
A. It is running a rogue web server B. It is being used in a man-in-the-middle attack C. It is participating in a botnet D. It is an ARP poisoning attack
Answer: C
Explanation: In this question, we have a source computer (192.10.3.204) sending data to a single destination IP address 10.10.1.5. No data is being received back by source computer which suggests the data being sent is some kind of Denial-of-service attack. This is common practice for computers participating in a botnet. The port used is TCP 6667 which is IRC (Internet Relay Chat). This port is used by many Trojans and is commonly used for DoS attacks.
Software running on infected computers called zombies is often known as a botnet. Bots, by themselves, are but a form of software that runs automatically and autonomously. (For example, Google uses the Googlebot to find web pages and bring back values for the index.) Botnet, however, has come to be the word used to describe malicious software running on a zombie and under the control of a bot-herder. Denial-of-service attacks—DoS and DDoS—can be launched by botnets, as can many forms of adware, spyware, and spam (via spambots). Most bots are written to run in the background with no visible evidence of their presence. Many malware kits can be used to create botnets and modify existing ones.
A user has plugged in a wireless router from home with default configurations into a network jack at the office. This is known as:
A. an evil twin. B. an IV attack. C. a rogue access point. D. an unauthorized entry point.
Answer: C
Explanation: A rogue access point is a wireless access point that should not be there. In this question, the wireless router has been connected to the corporate network without authorization. Therefore, it is a rogue access point. A rogue access point is a wireless access point that has either been installed on a secure company network without explicit authorization from a local network administrator, or has been created to allow a hacker to conduct a man-in-the-middle attack. Rogue access points of the first kind can pose a security threat to large organizations with many employees, because anyone with access to the premises can install (maliciously or non-maliciously) an inexpensive wireless router that can potentially allow access to a secure network to unauthorized parties. Rogue access points of the second kind target networks that do not employ mutual authentication (client-server server-client) and may be used in conjunction with a rogue RADIUS server, depending on security configuration of the target network. To prevent the installation of rogue access points, organizations can install wireless intrusion prevention systems to monitor the radio spectrum for unauthorized access points.
Ann, the network administrator, has learned from the helpdesk that employees are accessing the wireless network without entering their domain credentials upon connection. Once the connection is made, they cannot reach any internal resources, while wired network connections operate smoothly. Which of the following is MOST likely occurring?
A. A user has plugged in a personal access point at their desk to connect to the network wirelessly. B. The company is currently experiencing an attack on their internal DNS servers. C. The company’s WEP encryption has been compromised and WPA2 needs to be implemented instead. D. An attacker has installed an access point nearby in an attempt to capture company information.
Answer: D
Explanation: The question implies that users should be required to enter their domain credentials upon connection to the wireless network. The fact that they are connecting to a wireless network without being prompted for their domain credentials and they are unable to access network resources suggests they are connecting to a rogue wireless network. A rogue access point is a wireless access point that has either been installed on a secure company network without explicit authorization from a local network administrator, or has been created to allow a hacker to conduct a man-in-the-middle attack. Rogue access points of the first kind can pose a security threat to large organizations with many employees, because anyone with access to the premises can install (maliciously or non-maliciously) an inexpensive wireless router that can potentially allow access to a secure network to unauthorized parties. Rogue access points of the second kind target networks that do not employ mutual authentication (client-server server-client) and may be used in conjunction with a rogue RADIUS server, depending on security configuration of the target network. To prevent the installation of rogue access points, organizations can install wireless intrusion prevention systems to monitor the radio spectrum for unauthorized access points.
A company is concerned that a compromised certificate may result in a man-in-the-middle attack against backend financial servers. In order to minimize the amount of time a compromised certificate would be accepted by other servers, the company decides to add another validation step to SSL/TLS connections. Which of the following technologies provides the FASTEST revocation capability?
A. Online Certificate Status Protocol (OCSP) B. Public Key Cryptography (PKI) C. Certificate Revocation Lists (CRL) D. Intermediate Certificate Authority (CA)
Answer: A
Explanation: CRL (Certificate Revocation List) was first released to allow the CA to revoke certificates, however due to limitations with this method it was succeeded by OSCP. The main advantage to OCSP is that because the client is allowed query the status of a single certificate, instead of having to download and parse an entire list there is much less overhead on the client and network.
A computer supply company is located in a building with three wireless networks. The system security team implemented a quarterly security scan and saw the following. SSIDStateChannelLevel Computer AreUs1connected170dbm Computer AreUs2connected580dbm Computer AreUs3connected375dbm Computer AreUs4connected695dbm Which of the following is this an example of?
A. Rogue access point B. Near field communication C. Jamming D. Packet sniffing
Answer: A
Explanation: The question states that the building has three wireless networks. However, the scan is showing four wireless networks with the SSIDs: Computer AreUs1 , Computer AreUs2 , Computer AreUs3 and Computer AreUs4. Therefore, one of these wireless networks probably shouldn’t be there. This is an example of a rogue access point. A rogue access point is a wireless access point that has either been installed on a secure company network without explicit authorization from a local network administrator, or has been created to allow a hacker to conduct a man-in-the-middle attack. Rogue access points of the first kind can pose a security threat to large organizations with many employees, because anyone with access to the premises can install (maliciously or non-maliciously) an inexpensive wireless router that can potentially allow access to a secure network to unauthorized parties. Rogue access points of the second kind target networks that do not employ mutual authentication (client-server server-client) and may be used in conjunction with a rogue RADIUS server, depending on security configuration of the target network. To prevent the installation of rogue access points, organizations can install wireless intrusion prevention systems to monitor the radio spectrum for unauthorized access points.
Which of the following attacks could be used to initiate a subsequent man-in-the-middle attack?
A. ARP poisoning B. DoS C. Replay D. Brute force
Answer: C
Explanation: A replay attack (also known as playback attack) is a form of network attack in which a valid data transmission is maliciously or fraudulently repeated or delayed. This is carried out either by the originator or by an adversary who intercepts the data and retransmits it, possibly as part of a masquerade attack by IP packet substitution (such as stream cipher attack).
For example: Suppose Alice wants to prove her identity to Bob. Bob requests her password as proof of identity, which Alice dutifully provides (possibly after some transformation like a hash function); meanwhile, Eve is eavesdropping on the conversation and keeps the password (or the hash). After the interchange is over, Eve (posing as Alice) connects to Bob; when asked for a proof of identity, Eve sends Alice’s password (or hash) read from the last session, which Bob accepts thus granting access to Eve.
Countermeasures: A way to avoid replay attacks is by using session tokens: Bob sends a onetime token to Alice, which Alice uses to transform the password and send the result to Bob (e.g. computing a hash function of the session token appended to the password). On his side Bob performs the same computation; if and only if both values match, the login is successful. Now suppose Eve has captured this value and tries to use it on another session; Bob sends a different session token, and when Eve replies with the captured value it will be different from Bob’s computation. Session tokens should be chosen by a (pseudo-) random process. Otherwise Eve may be able to pose as Bob, presenting some predicted future token, and convince Alice to use that token in her transformation. Eve can then replay her reply at a later time (when the previously predicted token is actually presented by Bob), and Bob will accept the authentication. One-time passwords are similar to session tokens in that the password expires after it has been used or after a very short amount of time. They can be used to authenticate individual transactions in addition to sessions. The technique has been widely implemented in personal online banking systems. Bob can also send nonces but should then include a message authentication code (MAC), which Alice should check. Timestamping is another way of preventing a replay attack. Synchronization should be achieved using a secure protocol. For example Bob periodically broadcasts the time on his clock together with a MAC. When Alice wants to send Bob a message, she includes her best estimate of the time on his clock in her message, which is also authenticated. Bob only accepts messages for which the timestamp is within a reasonable tolerance. The advantage of this scheme is that Bob does not need to generate (pseudo-) random numbers, with the trade-off being that replay attacks, if they are performed quickly enough i.e. within that ‘reasonable’ limit, could succeed.
Which of the following is where an unauthorized device is found allowing access to a network?
A. Bluesnarfing B. Rogue access point C. Honeypot D. IV attack
Answer: B
Explanation: A rogue access point is a wireless access point that has either been installed on a secure company network without explicit authorization from a local network administrator, or has been created to allow a hacker to conduct a man-in-the-middle attack. Rogue access points of the first kind can pose a security threat to large organizations with many employees, because anyone with access to the premises can install (maliciously or non-maliciously) an inexpensive wireless router that can potentially allow access to a secure network to unauthorized parties. Rogue access points of the second kind target networks that do not employ mutual authentication (client-server server-client) and may be used in conjunction with a rogue RADIUS server, depending on security configuration of the target network. To prevent the installation of rogue access points, organizations can install wireless intrusion prevention systems to monitor the radio spectrum for unauthorized access points.
Which of the following protocols is vulnerable to man-in-the-middle attacks by NOT using end to end TLS encryption?
A. HTTPS B. WEP C. WPA D. WPA 2
Answer: B
Explanation: WEP offers no end-to-end TLS encryption.
The WEP process consists of a series of steps as follows: The wireless client sends an authentication request. The Access Point (AP) sends an authentication response containing clear-text (uh-oh!) challenge text. The client takes the challenge text received and encrypts it using a static WEP key. The client sends the encrypted authentication packet to the AP. The AP encrypts the challenge text using its own static WEP key and compares the result to the authentication packet sent by the client. If the results match, the AP begins the association process for the wireless client.
The big issue with WEP is the fact that it is very susceptible to a Man in the Middle attack. The attacker captures the clear-text challenge and then the authentication packet reply. The attacker then reverses the RC4 encryption in order to derive the static WEP key. Yikes! As you might guess, the designers attempted to strengthen WEP using the approach of key lengths. The native Windows client supported a 104-bit key as opposed to the initial 40-bit key. The fundamental weaknesses in the WEP process still remained however.
A disgruntled employee executes a man-in-the-middle attack on the company network. Layer 2 traffic destined for the gateway is redirected to the employee’s computer. This type of attack is an example of:
A. ARP cache poisoning B. IP spoofing C. amplified DNS attack D. evil twin