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ExplanationCross 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: Click Hereis equivalent to:Click HereNote: In the format “&#xhhhh“, hhhh is the code point in hexadecimal form.

ExplanationThe command “snmp-server user user-name group-name [remote ip-address [udp-port port]] {v1 | v2c | v3 [encrypted] [auth {md5 | sha} auth-password]} [access access-list]” adds a new user (in this case “andy”) to an SNMPv3 group (in this case group name “myv3”) and configures a password for the user.In the “snmp-server host” command, we need to:+ Specify the SNMP version with key word “version {1 | 2 | 3}”+ Specify the username (“andy”), not group name (“myv3”).Note: In “snmp-server host inside …” command, “inside” is the interface name of the ASA interface through which the NMS (located at 10.255.254.1) can be reached.

SQL injection attacks are a type of code injection technique that exploit the use of dynamic SQL queries in web applications. Attackers can inject malicious SQL statements into user input fields, such as login forms, search boxes, or URLs, and execute them on the underlying database. This can result in unauthorized access, data theft, data corruption, or denial of service.

To prevent SQL injection attacks, web developers should use the following techniques:

• Use prepared statements and parameterized queries: Prepared statements are SQL queries that are precompiled and executed with user-supplied parameters. Parameterized queries are SQL queries that use placeholders for user input and bind them to actual values at runtime. Both techniques separate the SQL code from the user input, making it impossible for attackers to inject SQL commands into the query. For example, in Java, PreparedStatement is a class that implements parameterized queries. In PHP, PDO and mysqli are extensions that support prepared statements.
• Block SQL code execution in the web application database login: Web applications should use a dedicated database user account with limited privileges to connect to the database. This account should only have the permissions necessary to perform the required operations, such as select, insert, update, or delete. It should not have the permissions to execute arbitrary SQL commands, such as create, drop, alter, grant, or revoke. This way, even if an attacker manages to inject SQL code into the query, the database will reject it due to insufficient privileges.

References:

• [Implementing and Operating Cisco Security Core Technologies (SCOR) v1.0], Module 5: Securing the Cloud, Lesson 5.2: Cloud Application Security, Topic 5.2.2: SQL Injection
• SQL Injection Prevention - OWASP Cheat Sheet Series
• How to Prevent SQL Injection: 5 Key Prevention Methods - eSecurityPlanet
• How to Protect Against SQL Injection Attacks