思科网络工程师题库3
思科网络工程师题库1-200Q1.In which form of attack is alternate encoding, such as hexadecimal representation, most often observed?A.SmurfB.distributed denial of serviceC.cross-site scriptingD.rootkit exploit Answer: C Explanation:Cross site scripting (also known as XSS) occurs when a web application gathers malicious data from a user. The data is usually gathered in the form of a hyperlink which contains malicious content within it. The user will most likely click on this link from another website, instant message, or simply just reading a web board or email message.Usually the attacker will encode the malicious portion of the link to the site in HEX (or other encoding methods) so the request is less suspicious looking to the user when clicked on. For example the code below is written in hex:<ahref=javascript:ale& #x72& #x 74('XSS')>Click Here</a>is equivalent to:<a href=javascript:alert('XSS')>Click Here</a>Note: In the format "&#xhhhh", hhhh is the code point in hexadecimal form.Q2.Which flaw does an attacker leverage when exploiting SQL injection vulnerabilities?A.user input validation in a web page or web applicationB.Linux and Windows operating systemsC.databaseD.web page images Answer: A Explanation:SQL injection usually occurs when you ask a user for input, like their username/userid, but the user gives ("injects") you an SQL statement that you will unknowingly run on your database. For example:Look at the following example, which creates a SELECT statement by adding a variable (txtUserId) to a select string.The variable is fetched from user input (getRequestString):txtUserId = getRequestString("UserId");txtSQL = "SELECT * FROM Users WHERE UserId = " + txtUserId; If user enter something like this: "100 OR 1=1" then the SQL statement will look like this:SELECT * FROM Users WHERE UserId = 100 OR 1=1;The SQL above is valid and will return ALL rows from the "Users" table, since OR 1=1 is always TRUE. A hacker might get access to all the user names and passwords in this database. Q3.Which two prevention techniques are used to mitigate SQL injection attacks? (Choose two)A.Check integer, float, or Boolean string parameters to ensure accurate values.B.Use prepared statements and parameterized queries.C.Secure the connection between the web and the app tier.D.Write SQL code instead of using object-relational mapping libraries.E.Block SQL code execution in the web application database login. Answer: AB Q4.Which two endpoint measures are used to minimize the chances of falling victim to phishing and social engineering attacks? (Choose two)A.Patch for cross-site scripting.B.Perform backups to the private cloud.C.Protect against input validation and character escapes in the endpoint.D.Install a spam and virus email filter.E.Protect systems with an up-to-date antimalware program. Answer: DEExplanation:Phishing attacks are the practice of sending fraudulent communications that appear to come from a reputable source. It is usually done through email. The goal is to steal sensitive data like credit card and login information, or to install malware on the victim's machine.Q5.Which two mechanisms are used to control phishing attacks? (Choose two)A.Enable browser alerts for fraudulent websites.B.Define security group memberships.C.Revoke expired CRL of the websites.D.Use antispyware software.E.Implement email filtering techniques. Answer: AEQ6.Which two behavioral patterns characterize a ping of death attack? (Choose two)A.The attack is fragmented into groups of 16 octets before transmission.B.The attack is fragmented into groups of 8 octets before transmission.C.Short synchronized bursts of traffic are used to disrupt TCP connections.D.Malformed packets are used to crash systems.E.Publicly accessible DNS servers are typically used to execute the attack. Answer: BDExplanation:Ping of Death (PoD) is a type of Denial of Service (DoS) attack in which an attacker attempts to crash, destabilize, or freeze the targeted computer or service by sending malformed or oversized packets using a simple ping command.A correctly-formed ping packet is typically 56 bytes in size, or 64 bytes when the ICMP header is considered, and 84 including Internet Protocol version 4 header. However, any IPv4 packet (including pings) may be as large as 65,535 bytes. Some computer systems were never designed to properly handle a ping packet larger than the maximum packet size because it violates the Internet Protocol documented Like other large but well-formed packets, a ping of death is fragmented into groups of 8 octets before transmission. However, when the target computer reassembles the malformed packet, a buffer overflow can occur, causing a system cr
