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Find command injection vulnerabilities

Recipe IDorg.openrewrite.analysis.java.security.FindCommandInjection
Artifactio.moderne.recipe:rewrite-program-analysis

Detects when user-controlled input flows into system command execution methods like Runtime.exec() or ProcessBuilder, which could allow attackers to execute arbitrary commands.

Single recipeOpenRewriteModerne Proprietary License
Try in PlatformTry this recipe in the Moderne platform. Not a user yet? You’ll get a no-setup demo environment, with nothing to install or configure.

Examples​

java
Before
import javax.servlet.http.HttpServletRequest;

class Test {
    void method(HttpServletRequest request) throws Exception {
        String[] commands = new String[10];
        commands[0] = request.getParameter("cmd");
        Runtime.getRuntime().exec(commands[0]);
    }
}
After
import javax.servlet.http.HttpServletRequest;

class Test {
    void method(HttpServletRequest request) throws Exception {
        String[] commands = new String[10];
        commands[0] = request.getParameter("cmd");
        /*~~(COMMAND_INJECTION use)~~>*/Runtime.getRuntime().exec(commands[0]);
    }
}
java
Before
class CommandExecutor {
    void execute() throws Exception {
        String cmd = System.getProperty("user.command");
        Runtime.getRuntime().exec(cmd);
    }
}
After
class CommandExecutor {
    void execute() throws Exception {
        String cmd = System.getProperty("user.command");
        /*~~(Command injection risk)~~>*/Runtime.getRuntime().exec(cmd);
    }
}
Example 3
Unchanged
import javax.servlet.http.HttpServletRequest;

public class ContextExample {
    private String command;

    // Safe context - called with hardcoded value
    public void initSafe() {
        setCommand("ls -la");
    }

    // Unsafe context - called with user input
    public void initUnsafe(HttpServletRequest request) {
        String userCmd = request.getParameter("cmd");
        setCommand(userCmd);
    }

    // Helper method that sets the field
    private void setCommand(String cmd) {
        this.command = cmd;
    }

    // Uses the field - should only be flagged if initUnsafe was called
    public void execute() throws Exception {
        Runtime.getRuntime().exec(this.command);
    }
}
java
Before
import javax.servlet.http.HttpServletRequest;

class CommandExecutor {
    void execute(HttpServletRequest request) throws Exception {
        String cmd = request.getParameter("command");
        Runtime.getRuntime().exec(cmd);
    }
}
After
import javax.servlet.http.HttpServletRequest;

class CommandExecutor {
    void execute(HttpServletRequest request) throws Exception {
        String cmd = request.getParameter("command");
        /*~~(COMMAND_INJECTION use)~~>*/Runtime.getRuntime().exec(cmd);
    }
}
java
Before
import javax.servlet.http.HttpServletRequest;
import java.util.function.Consumer;

class CommandProcessor {
    void process(HttpServletRequest request) throws Exception {
        String cmd = request.getParameter("command");
        Consumer<String> executor = Runtime.getRuntime()::exec;
        executor.accept(cmd);
    }
}
After
import javax.servlet.http.HttpServletRequest;
import java.util.function.Consumer;

class CommandProcessor {
    void process(HttpServletRequest request) throws Exception {
        String cmd = request.getParameter("command");
        Consumer<String> executor = Runtime.getRuntime()::exec;
        /*~~>*/executor.accept(cmd);
    }
}
java
Before
import javax.servlet.http.HttpServletRequest;
import java.util.Arrays;
import java.util.List;

class Test {
    void method(HttpServletRequest request) {
        List<String> commands = Arrays.asList(
            request.getParameter("cmd1"),
            request.getParameter("cmd2")
        );
        commands.forEach(this::executeCommand);
    }

    void executeCommand(String cmd) {
        try {
            Runtime.getRuntime().exec(cmd);
        } catch (Exception e) {
            // ignore
        }
    }
}
After
import javax.servlet.http.HttpServletRequest;
import java.util.Arrays;
import java.util.List;

class Test {
    void method(HttpServletRequest request) {
        List<String> commands = Arrays.asList(
            request.getParameter("cmd1"),
            request.getParameter("cmd2")
        );
        commands.forEach(this::executeCommand);
    }

    void executeCommand(String cmd) {
        try {
            /*~~(COMMAND_INJECTION use)~~>*/Runtime.getRuntime().exec(cmd);
        } catch (Exception e) {
            // ignore
        }
    }
}
java
Before
import javax.servlet.http.HttpServletRequest;

public class StepByStep {
    public void handleRequest(HttpServletRequest request) throws Exception {
        // Step 1: Get tainted value
        String tainted = request.getParameter("cmd");

        // Step 2: Pass through transform
        String transformed = transform(tainted);

        // Step 3: Use in sink
        Runtime.getRuntime().exec(transformed);
    }

    private String transform(String input) {
        return "cmd " + input;
    }
}
After
import javax.servlet.http.HttpServletRequest;

public class StepByStep {
    public void handleRequest(HttpServletRequest request) throws Exception {
        // Step 1: Get tainted value
        String tainted = request.getParameter("cmd");

        // Step 2: Pass through transform
        String transformed = transform(tainted);

        // Step 3: Use in sink
        /*~~(COMMAND_INJECTION use)~~>*/Runtime.getRuntime().exec(transformed);
    }

    private String transform(String input) {
        return "cmd " + input;
    }
}
java
Before
import javax.servlet.http.HttpServletRequest;

public class ChainedCalls {
    public void handleRequest(HttpServletRequest request) throws Exception {
        // Taint should flow through the chain
        String cmd = request.getParameter("cmd")
            .trim()
            .toUpperCase()
            .replace("BAD", "GOOD");
        Runtime.getRuntime().exec(cmd);
    }
}
After
import javax.servlet.http.HttpServletRequest;

public class ChainedCalls {
    public void handleRequest(HttpServletRequest request) throws Exception {
        // Taint should flow through the chain
        String cmd = request.getParameter("cmd")
            .trim()
            .toUpperCase()
            .replace("BAD", "GOOD");
        /*~~>*/Runtime.getRuntime().exec(cmd);
    }
}

Usage​

Run this recipe

This recipe has no required configuration options. Users of Moderne can run it via the Moderne CLI.

You will need to have configured the Moderne CLI on your machine before you can run the following command.

shell
mod run . --recipe FindCommandInjection

If the recipe is not available locally, then you can install it using:

mod config recipes jar install io.moderne.recipe:rewrite-program-analysis:0.13.1

Data tables​

Taint flow
org.openrewrite.analysis.java.taint.table.TaintFlowTable

Records taint flows from sources to sinks with their taint types.

ColumnDescription
Source fileThe source file that the method call occurred in.
Source lineThe line number where the taint source is located.
SourceThe source code where taint originates.
Sink lineThe line number where the taint sink is located.
SinkThe sink code where taint flows to.
Taint typeThe taint type that matched at the sink.
Source files that had results
org.openrewrite.table.SourcesFileResults

Source files that were modified by the recipe run.

ColumnDescription
Source path before the runThe source path of the file before the run. null when a source file was created during the run.
Source path after the runA recipe may modify the source path. This is the path after the run. null when a source file was deleted during the run.
Parent of the recipe that made changesIn a hierarchical recipe, the parent of the recipe that made a change. Empty if this is the root of a hierarchy or if the recipe is not hierarchical at all.
Recipe that made changesThe specific recipe that made a change.
Estimated time savingAn estimated effort that a developer to fix manually instead of using this recipe, in unit of seconds.
CycleThe recipe cycle in which the change was made.
Source files that had search results
org.openrewrite.table.SearchResults

Search results that were found during the recipe run.

ColumnDescription
Source path of search result before the runThe source path of the file with the search result markers present.
Source path of search result after run the runA recipe may modify the source path. This is the path after the run. null when a source file was deleted during the run.
ResultThe trimmed printed tree of the LST element that the marker is attached to.
DescriptionThe content of the description of the marker.
Recipe that added the search markerThe specific recipe that added the Search marker.
Source files that errored on a recipe
org.openrewrite.table.SourcesFileErrors

The details of all errors produced by a recipe run.

ColumnDescription
Source pathThe file that failed to parse.
Recipe that made changesThe specific recipe that made a change.
Stack traceThe stack trace of the failure.
Recipe performance
org.openrewrite.table.RecipeRunStats

Statistics used in analyzing the performance of recipes.

ColumnDescription
The recipeThe recipe whose stats are being measured both individually and cumulatively.
Source file countThe number of source files the recipe ran over.
Source file changed countThe number of source files which were changed in the recipe run. Includes files created, deleted, and edited.
Cumulative scanning time (ns)The total time spent across the scanning phase of this recipe.
Max scanning time (ns)The max time scanning any one source file.
Cumulative edit time (ns)The total time spent across the editing phase of this recipe.
Max edit time (ns)The max time editing any one source file.