EC-COUNCIL EC-COUNCIL Certifications 312-50 Questions & Answers

• Question 521:

  You have been using the msadc.pl attack script to execute arbitrary commands on an NT4 web server. While it is effective, you find it tedious to perform extended functions. On further research you come across a perl script that runs the following msadc functions: What kind of exploit is indicated by this script?

  

  A. A buffer overflow exploit.

  B. A SUID exploit.

  C. A SQL injection exploit.

  D. A chained exploit.

  E. A buffer under run exploit.

  Correct Answer: D

• Question 522:

  Study the following exploit code taken from a Linux machine and answer the questions below:

  echo "ingreslock stream tcp nowait root /bin/sh sh I" > /tmp/x; /usr/sbin/inetd s /tmp/x; sleep 10; /bin/ rm f /tmp/x AAAA...AAA

  In the above exploit code, the command "/bin/sh sh I" is given.

  What is the purpose, and why is `sh' shown twice?

  A. The command /bin/sh sh i appearing in the exploit code is actually part of an inetd configuration file.

  B. The length of such a buffer overflow exploit makes it prohibitive for user to enter manually.The second `sh' automates this function.

  C. It checks for the presence of a codeword (setting the environment variable) among the environment variables.

  D. It is a giveaway by the attacker that he is a script kiddy.

  Correct Answer: A

  What's going on in the above question is the attacker is trying to write to the unix filed /tm/x (his inetd.conf replacement config) -- he is attempting to add a service called ingresslock (which doesnt exist), which is "apparently" suppose to spawn a shell the given port specified by /etc/services for the service "ingresslock", ingresslock is a non-existant service, and if an attempt were made to respawn inetd, the service would error out on that line. (he would have to add the service to / etc/services to suppress the error). Now the question is asking about /bin/sh sh -i which produces an error that should read "sh: /bin/sh: cannot execute binary file", the -i option places the shell in interactive mode and cannot be used to respawn itself.

• Question 523:

  Which of the following encryption is not based on Block Cipher?

  A. DES

  B. Blowfish

  C. AES

  D. RC4

  Correct Answer: D

  RC4 (also known as ARC4 or ARCFOUR) is the most widely-used software stream cipher and is used in popular protocols such as Secure Sockets Layer (SSL) (to protect Internet traffic) and WEP (to secure wireless networks).

• Question 524:

  One of the most common and the best way of cracking RSA encryption is to being to derive the two prime numbers, which are used in the RSA PKI mathematical process. If the two numbers p and q are discovered through a _________________ process, then the private key can be derived.

  A. Factorization

  B. Prime Detection

  C. Hashing

  D. Brute-forcing

  Correct Answer: A

  In April 1994, an international cooperative group of mathematicians and computer scientists solved a 17-year-old challenge problem, the factoring of a 129-digit number, called RSA-129, into two primes. That is, RSA-129 = 1143816257578888676692357799761466120102182 9672124236256256184293570693524573389783059 7123563958705058989075147599290026879543541 = 34905295108476509491478496199038 98133417764638493387843990820577 times 32769132993266709549961988190834 461413177642967992942539798288533. Se more at http://en.wikipedia.org/wiki/RSA_Factoring_Challenge

• Question 525:

  Microsoft Authenticode technology is used for:

  A. Digital Signing Activex controls

  B. Digitally signing SSL Certificates

  C. Digitally Signing JavaScript Files

  D. Digitally Signing Java Applets

  Correct Answer: A

  Authenticode identifies the publisher of signed software and verifies that it hasn't been tampered with, before users download software to their PCs. As a result, end users can make a more informed decision as to whether or not to download code. Authenticode relies on digital certificates and is based on specifications that have been used successfully in the industry for some time, including Public Key Cryptography Standards (PKCS) #7 (encrypted key specification), PKCS #10 (certificate request formats), X.509 (certificate specification), and Secure Hash Algorithm (SHA) and MD5 hash algorithms.

• Question 526:

  A digital signature is simply a message that is encrypted with the public key instead of the private key.

  A. True

  B. False

  Correct Answer: B

  Digital signatures enable the recipient of information to verify the authenticity of the information's origin, and also verify that the information is intact. Thus, public key digital signatures provide authentication and data integrity. A digital signature also provides non-repudiation, which means that it prevents the sender from claiming that he or she did not actually send the information. Instead of encrypting information using someone else's public key, you encrypt it with your private key. If the information can be decrypted with your public key, then it must have originated with you.

• Question 527:

  Richard is a network Administrator working at a student loan company in lowa. This company processes over 20,000 students loan a year from colleges all over the state. Most communication between the company, schools and lenders is carried out through email. Because of privacy laws that are in the process of being implemented, Richard wants to get ahead of the game and become compliant before any sort of auditing occurs. Much of the email communication used at his company contains sensitive information such as social security numbers. For this reason, Richard wants to utilize email encryption agency-wide. The only problem for Richard is that his department only has couple of servers and they are utilized to their full capacity. Since a server-based PKI is not an option for him, he is looking for a low/no cost solution to encrypt email.

  What should Richard use?

  A. PGP

  B. RSA

  C. 3DES

  D. OTP

  Correct Answer: A

  PGP (Pretty Good Privacy) is an encryption program being used for secure transmission of files and e- mails. This adapts public-key encryption technology in which pairs of keys are used to maintain secure communication. For PGP-based communication both the sender and receiver should have public and private key pairs. The sender's public key should be distributed to the receiver. Similarly, the receiver's public key should be distributed to the sender. When sending a message or a file, the sender can sign using his private key. Also, the sender's private key is never distributed. All encryption is made on the workstation sending the e-mail.

• Question 528:

  What are the different between SSL and S-HTTP?

  A. SSL operates at the network layer and S-HTTP operates at the application layer

  B. SSL operates at the application layer and S-HTTP operates at the network layer

  C. SSL operates at transport layer and S-HTTP operates at the application layer

  D. SSL operates at the application layer and S-HTTP operates at the transport layer

  Correct Answer: C

  Whereas SSL is designed to establish a secure connection between two computers, S-HTTP is designed to send individual messages securely. S-HTTP is defined in RFC 2660

• Question 529:

  One of the most common and the best way of cracking RSA encryption is to being to derive the two prime numbers, which are used in the RSA PKI mathematical process. If the two numbers p and q are discovered through a _________________ process, then the private key can be derived.

  A. Factorization

  B. Prime Detection

  C. Hashing

  D. Brute-forcing

  Correct Answer: A

  In April 1994, an international cooperative group of mathematicians and computer scientists solved a 17-year-old challenge problem, the factoring of a 129-digit number, called RSA-129, into two primes. That is, RSA-129 = 1143816257578888676692357799761466120102182 9672124236256256184293570693524573389783059 7123563958705058989075147599290026879543541 = 34905295108476509491478496199038 98133417764638493387843990820577 times 32769132993266709549961988190834 461413177642967992942539798288533. Se more at http://en.wikipedia.org/wiki/RSA_Factoring_Challenge

• Question 530:

  Bob is a Junior Administrator at ABC Company. He is installing the RedHat Enterprise Linux on his machine. At installation time, he removed the "Use MD5" options. What will be the hashing standard?

  A. MD2

  B. DES

  C. 3DES

  D. RSA

  Correct Answer: B

  crypt() will return an encrypted string using the standard Unix DES-based encryption algorithm or alternative algorithms that may be available on the system. By removing the "Use MD5" option Bob forces crypt() to revert to DES encryption.