CAPEC-108: Command Line Execution through SQL Injection
CAPEC版本: 3.9
更新日期: 2023-01-24
攻击模式描述
An attacker uses standard SQL injection methods to inject data into the command line for execution. This could be done directly through misuse of directives such as MSSQL_xp_cmdshell or indirectly through injection of data into the database that would be interpreted as shell commands. Sometime later, an unscrupulous backend application (or could be part of the functionality of the same application) fetches the injected data stored in the database and uses this data as command line arguments without performing proper validation. The malicious data escapes that data plane by spawning new commands to be executed on the host.
执行流程
步骤 1 Explore
[Probe for SQL Injection vulnerability] The attacker injects SQL syntax into user-controllable data inputs to search unfiltered execution of the SQL syntax in a query.
步骤 2 Exploit
[Achieve arbitrary command execution through SQL Injection with the MSSQL_xp_cmdshell directive] The attacker leverages a SQL Injection attack to inject shell code to be executed by leveraging the xp_cmdshell directive.
步骤 3 Exploit
[Inject malicious data in the database] Leverage SQL injection to inject data in the database that could later be used to achieve command injection if ever used as a command line argument
步骤 4 Exploit
[Trigger command line execution with injected arguments] The attacker causes execution of command line functionality which leverages previously injected database content as arguments.
前提条件
- The application does not properly validate data before storing in the database
- Backend application implicitly trusts the data stored in the database
- Malicious data is used on the backend as a command line argument
所需技能
所需资源
- None: No specialized resources are required to execute this type of attack.
后果影响
影响范围: Integrity
技术影响: Modify Data
影响范围: Confidentiality
技术影响: Read Data
影响范围: Availability
技术影响: Unreliable Execution
影响范围: Confidentiality Access Control Authorization
技术影响: Gain Privileges
影响范围: Confidentiality Integrity Availability
技术影响: Execute Unauthorized Commands
说明: Run Arbitrary Code
缓解措施
Disable MSSQL xp_cmdshell directive on the database
Properly validate the data (syntactically and semantically) before writing it to the database.
Do not implicitly trust the data stored in the database. Re-validate it prior to usage to make sure that it is safe to use in a given context (e.g. as a command line argument).