Improving Web Application Security: Threats and - CGISecurity

Chapter 18: Securing Your Database Server 505AttacksDirect connection attacks exist for both authenticated users and those without a username and password; for example:● Tools such as Query Analyzer (Isqlw.exe) or the command line equivalent(Osql.exe) are used to establish a direct connection to SQL Server and issuecommands.● Server information, such as software version, is revealed to an attacker who sendscarefully constructed packets to listening ports.CountermeasuresTo counter these attacks:● Make sure that SQL Server ports are not visible from outside of the perimeternetwork.● Within the perimeter, restrict direct access by unauthorized hosts, for example, byusing IPSec or TCP/IP filters.Password CrackingA common first line of attack is to try to crack the passwords of well known accountnames, such as sa (the SQL Server administrator account).VulnerabilitiesCommon vulnerabilities that lead to password cracking are:●●Weak or blank passwordsPasswords that contain everyday wordsAttacksCommon password cracking attacks include:●●Dictionary attacksManual password guessingCountermeasuresTo counter these attacks:●●Create passwords for SQL Server login accounts that meet complexityrequirements.Avoid passwords that contain common words found in the dictionary.Note If you use Windows authentication, password complexity can be enforced by Windowssecurity policy.