Vulnerabilities > CVE-2023-36830 - Injection vulnerability in Sqlfluff
Summary
SQLFluff is a SQL linter. Prior to version 2.1.2, in environments where untrusted users have access to the config files, there is a potential security vulnerability where those users could use the `library_path` config value to allow arbitrary python code to be executed via macros. For many users who use SQLFluff in the context of an environment where all users already have fairly escalated privileges, this may not be an issue - however in larger user bases, or where SQLFluff is bundled into another tool where developers still wish to give users access to supply their on rule configuration, this may be an issue. The 2.1.2 release offers the ability for the `library_path` argument to be overwritten on the command line by using the `--library-path` option. This overrides any values provided in the config files and effectively prevents this route of attack for users which have access to the config file, but not to the scripts which call the SQLFluff CLI directly. A similar option is provided for the Python API, where users also have a greater ability to further customise or override configuration as necessary. Unless `library_path` is explicitly required, SQLFluff maintainers recommend using the option `--library-path none` when invoking SQLFluff which will disable the `library-path` option entirely regardless of the options set in the configuration file or via inline config directives. As a workaround, limiting access to - or otherwise validating configuration files before they are ingested by SQLFluff will provides a similar effect and does not require upgrade.
Vulnerable Configurations
Common Weakness Enumeration (CWE)
Common Attack Pattern Enumeration and Classification (CAPEC)
- Buffer Overflow via Environment Variables This attack pattern involves causing a buffer overflow through manipulation of environment variables. Once the attacker finds that they can modify an environment variable, they may try to overflow associated buffers. This attack leverages implicit trust often placed in environment variables.
- Server Side Include (SSI) Injection An attacker can use Server Side Include (SSI) Injection to send code to a web application that then gets executed by the web server. Doing so enables the attacker to achieve similar results to Cross Site Scripting, viz., arbitrary code execution and information disclosure, albeit on a more limited scale, since the SSI directives are nowhere near as powerful as a full-fledged scripting language. Nonetheless, the attacker can conveniently gain access to sensitive files, such as password files, and execute shell commands.
- Cross Site Scripting through Log Files An attacker may leverage a system weakness where logs are susceptible to log injection to insert scripts into the system's logs. If these logs are later viewed by an administrator through a thin administrative interface and the log data is not properly HTML encoded before being written to the page, the attackers' scripts stored in the log will be executed in the administrative interface with potentially serious consequences. This attack pattern is really a combination of two other attack patterns: log injection and stored cross site scripting.
- Command Line Execution through SQL Injection 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.
- Subverting Environment Variable Values The attacker directly or indirectly modifies environment variables used by or controlling the target software. The attacker's goal is to cause the target software to deviate from its expected operation in a manner that benefits the attacker.