Improving Web Application Security: Threats and - CGISecurity

504 Part IV: Securing Your Network, Host and Application●Use a SQL Server login that has restricted permissions in the database. Ideally, youshould grant execute permissions only to selected stored procedures in thedatabase and provide no direct table access.For more information about application-level countermeasures to SQL injectionattacks, see Chapter 14, “Building Secure Data Access.”Network EavesdroppingThe deployment architecture of most applications includes a physical separation ofthe data access code from the database server. As a result, sensitive data, such asapplication-specific data or database login credentials, must be protected fromnetwork eavesdroppers.VulnerabilitiesVulnerabilities that increase the likelihood of network eavesdropping include:● Insecure communication channels● Passing credentials in clear text to the database; for example:●●Using SQL authentication instead of Windows authenticationUsing SQL authentication without a server certificateCountermeasuresTo counter network eavesdropping:●●●●Use Windows authentication to connect to the database server to avoid sendingcredentials over the network.Install a server certificate on the database server. This results in the automaticencryption of SQL credentials over the network.Use an SSL connection between the Web server and database server to protectsensitive application data. This requires a database server certificate.Use an IPSec encrypted channel between Web and database server.Unauthorized Server AccessDirect access to your database server should be restricted to specific client computersto prevent unauthorized server access.VulnerabilitiesVulnerabilities that make your database server susceptible to unauthorized serveraccess include:● Failure to block the SQL Server port at the perimeter firewall● Lack of IPSec or TCP/IP filtering policies