Java: Promote Server-side template injection from experimental

java/ql/lib/semmle/code/java/dataflow/ExternalFlow.qll

@@ -117,6 +117,7 @@ private module Frameworks {
   private import semmle.code.java.frameworks.Retrofit
   private import semmle.code.java.frameworks.Stream
   private import semmle.code.java.frameworks.Strings
+  private import semmle.code.java.frameworks.Thymeleaf
   private import semmle.code.java.frameworks.ratpack.Ratpack
   private import semmle.code.java.frameworks.ratpack.RatpackExec
   private import semmle.code.java.frameworks.spring.SpringCache
@@ -141,6 +142,7 @@ private module Frameworks {
   private import semmle.code.java.security.LdapInjection
   private import semmle.code.java.security.MvelInjection
   private import semmle.code.java.security.OgnlInjection
+  private import semmle.code.java.security.TemplateInjection
   private import semmle.code.java.security.XPath
   private import semmle.code.java.security.XsltInjection
   private import semmle.code.java.frameworks.Jdbc
@@ -625,7 +627,7 @@ module CsvValidation {
           "open-url", "jndi-injection", "ldap", "sql", "jdbc-url", "logging", "mvel", "xpath",
           "groovy", "xss", "ognl-injection", "intent-start", "pending-intent-sent",
           "url-open-stream", "url-redirect", "create-file", "write-file", "set-hostname-verifier",
-          "header-splitting", "information-leak", "xslt", "jexl", "bean-validation"
+          "header-splitting", "information-leak", "xslt", "jexl", "bean-validation", "ssti"
         ] and
       not kind.matches("regex-use%") and
       not kind.matches("qltest%") and

java/ql/lib/semmle/code/java/frameworks/Thymeleaf.qll

@@ -0,0 +1,16 @@
+/**
+ * Provides classes and predicates for working with the Thymeleaf template engine.
+ */
+
+import java
+private import semmle.code.java.dataflow.ExternalFlow
+
+private class ThymeleafSummaryModels extends SummaryModelCsv {
+  override predicate row(string row) {
+    row =
+      [
+        "org.thymeleaf;TemplateSpec;false;TemplateSpec;;;Argument[0];Argument[-1];taint;manual",
+        "org.thymeleaf;TemplateSpec;false;getTemplate;;;Argument[-1];ReturnValue;taint;manual",
+      ]
+  }
+}

java/ql/lib/semmle/code/java/security/TemplateInjection.qll

@@ -0,0 +1,108 @@
+/** Definitions related to the server-side template injection (SST) query. */
+
+import java
+private import semmle.code.java.dataflow.FlowSources
+private import semmle.code.java.dataflow.ExternalFlow
+private import semmle.code.java.dataflow.TaintTracking
+
+/**
+ * A source for server-side template injection (SST) vulnerabilities.
+ */
+abstract class TemplateInjectionSource extends DataFlow::Node {
+  /** Holds if this source has the specified `state`. */
+  predicate hasState(DataFlow::FlowState state) { state instanceof DataFlow::FlowStateEmpty }
+}
+
+/**
+ * A sink for server-side template injection (SST) vulnerabilities.
+ */
+abstract class TemplateInjectionSink extends DataFlow::Node {
+  /** Holds if this sink has the specified `state`. */
+  predicate hasState(DataFlow::FlowState state) { state instanceof DataFlow::FlowStateEmpty }
+}
+
+/**
+ * A unit class for adding additional taint steps.
+ *
+ * Extend this class to add additional taint steps that should apply to flows related to
+ * server-side template injection (SST) vulnerabilities.
+ */
+class TemplateInjectionAdditionalTaintStep extends Unit {
+  /**
+   * Holds if the step from `node1` to `node2` should be considered a taint
+   * step for flows related to server-side template injection (SST) vulnerabilities.
+   */
+  predicate isAdditionalTaintStep(DataFlow::Node node1, DataFlow::Node node2) { none() }
+
+  /**
+   * Holds if the step from `node1` to `node2` should be considered a taint
+   * step for flows related toserver-side template injection (SST) vulnerabilities.
+   * This step is only applicable in `state1` and updates the flow state to `state2`.
+   */
+  predicate isAdditionalTaintStep(
+    DataFlow::Node node1, DataFlow::FlowState state1, DataFlow::Node node2,
+    DataFlow::FlowState state2
+  ) {
+    none()
+  }
+}
+
+/**
+ * A sanitizer for server-side template injection (SST) vulnerabilities.
+ */
+abstract class TemplateInjectionSanitizer extends DataFlow::Node { }
+
+/**
+ * A sanitizer for server-side template injection (SST) vulnerabilities.
+ * This sanitizer is only applicable when `TemplateInjectionSanitizerWithState::hasState`
+ * holds for the flow state.
+ */
+abstract class TemplateInjectionSanitizerWithState extends DataFlow::Node {
+  /** Holds if this sanitizer has the specified `state`. */
+  abstract predicate hasState(DataFlow::FlowState state);
+}
+
+private class DefaultTemplateInjectionSource extends TemplateInjectionSource instanceof RemoteFlowSource {
+}
+
+private class DefaultTemplateInjectionSink extends TemplateInjectionSink {
+  DefaultTemplateInjectionSink() { sinkNode(this, "ssti") }
+}
+
+private class DefaultTemplateInjectionSanitizer extends TemplateInjectionSanitizer {
+  DefaultTemplateInjectionSanitizer() {
+    this.getType() instanceof PrimitiveType or
+    this.getType() instanceof BoxedType or
+    this.getType() instanceof NumericType
+  }
+}
+
+private class TemplateInjectionSinkModels extends SinkModelCsv {
+  override predicate row(string row) {
+    row =
+      [
+        "freemarker.template;Template;true;Template;(String,Reader);;Argument[1];ssti;manual",
+        "freemarker.template;Template;true;Template;(String,Reader,Configuration);;Argument[1];ssti;manual",
+        "freemarker.template;Template;true;Template;(String,Reader,Configuration,String);;Argument[1];ssti;manual",
+        "freemarker.template;Template;true;Template;(String,String,Reader,Configuration);;Argument[2];ssti;manual",
+        "freemarker.template;Template;true;Template;(String,String,Reader,Configuration,String);;Argument[2];ssti;manual",
+        "freemarker.template;Template;true;Template;(String,String,Reader,Configuration,ParserConfiguration,String);;Argument[2];ssti;manual",
+        "freemarker.template;Template;true;Template;(String,String,Configuration);;Argument[1];ssti;manual",
+        "freemarker.cache;StringTemplateLoader;true;putTemplate;;;Argument[1];ssti;manual",
+        "com.mitchellbosecke.pebble;PebbleEngine;true;getTemplate;;;Argument[0];ssti;manual",
+        "com.mitchellbosecke.pebble;PebbleEngine;true;getLiteralTemplate;;;Argument[0];ssti;manual",
+        "com.hubspot.jinjava;Jinjava;true;renderForResult;;;Argument[0];ssti;manual",
+        "com.hubspot.jinjava;Jinjava;true;render;;;Argument[0];ssti;manual",
+        "org.thymeleaf;ITemplateEngine;true;process;;;Argument[0];ssti;manual",
+        "org.thymeleaf;ITemplateEngine;true;processThrottled;;;Argument[0];ssti;manual",
+        "org.apache.velocity.app;Velocity;true;evaluate;;;Argument[3];ssti;manual",
+        "org.apache.velocity.app;Velocity;true;mergeTemplate;;;Argument[2];ssti;manual",
+        "org.apache.velocity.app;VelocityEngine;true;evaluate;;;Argument[3];ssti;manual",
+        "org.apache.velocity.app;VelocityEngine;true;mergeTemplate;;;Argument[2];ssti;manual",
+        "org.apache.velocity.runtime.resource.util;StringResourceRepository;true;putStringResource;;;Argument[1];ssti;manual",
+        "org.apache.velocity.runtime;RuntimeServices;true;evaluate;;;Argument[3];ssti;manual",
+        "org.apache.velocity.runtime;RuntimeServices;true;parse;;;Argument[0];ssti;manual",
+        "org.apache.velocity.runtime;RuntimeSingleton;true;parse;;;Argument[0];ssti;manual"
+      ]
+  }
+}

java/ql/lib/semmle/code/java/security/TemplateInjectionQuery.qll

@@ -0,0 +1,38 @@
+/** Provides a taint tracking configuration for server-side template injection (SST) vulnerabilities */
+
+import java
+import semmle.code.java.dataflow.TaintTracking
+import semmle.code.java.dataflow.FlowSources
+import semmle.code.java.security.TemplateInjection
+
+/** A taint tracking configuration to reason about server-side template injection (SST) vulnerabilities */
+class TemplateInjectionFlowConfig extends TaintTracking::Configuration {
+  TemplateInjectionFlowConfig() { this = "TemplateInjectionFlowConfig" }
+
+  override predicate isSource(DataFlow::Node source, DataFlow::FlowState state) {
+    source.(TemplateInjectionSource).hasState(state)
+  }
+
+  override predicate isSink(DataFlow::Node sink, DataFlow::FlowState state) {
+    sink.(TemplateInjectionSink).hasState(state)
+  }
+
+  override predicate isSanitizer(DataFlow::Node sanitizer) {
+    sanitizer instanceof TemplateInjectionSanitizer
+  }
+
+  override predicate isSanitizer(DataFlow::Node sanitizer, DataFlow::FlowState state) {
+    sanitizer.(TemplateInjectionSanitizerWithState).hasState(state)
+  }
+
+  override predicate isAdditionalTaintStep(DataFlow::Node node1, DataFlow::Node node2) {
+    any(TemplateInjectionAdditionalTaintStep a).isAdditionalTaintStep(node1, node2)
+  }
+
+  override predicate isAdditionalTaintStep(
+    DataFlow::Node node1, DataFlow::FlowState state1, DataFlow::Node node2,
+    DataFlow::FlowState state2
+  ) {
+    any(TemplateInjectionAdditionalTaintStep a).isAdditionalTaintStep(node1, state1, node2, state2)
+  }
+}

java/ql/src/Security/CWE/CWE-094/TemplateInjection.qhelp

@@ -0,0 +1,32 @@
+<!DOCTYPE qhelp PUBLIC "-//Semmle//qhelp//EN" "qhelp.dtd">
+<qhelp>
+<overview>
+<p>
+Template injection occurs when user input is embedded in a template's code in an unsafe manner.
+An attacker can use native template syntax to inject a malicious payload into a template, which is then executed server-side.
+This permits the attacker to run arbitrary code in the server's context.
+</p>
+</overview>
+<recommendation>
+<p>
+To fix this, ensure that untrusted input is not used as part of a template's code. If the application requirements do not allow this,
+use a sandboxed environment where access to unsafe attributes and methods is prohibited.
+</p>
+</recommendation>
+<example>
+<p>
+In the example given below, an untrusted HTTP parameter <code>code</code> is used as a Velocity template string. 
+This can lead to remote code execution.
+</p>
+<sample src="SSTIBad.java" />
+
+<p>
+In the next example, the problem is avoided by using a fixed template string <code>s</code>.
+Since the template's code is not attacker-controlled in this case, this solution prevents the execution of untrusted code.
+</p>
+<sample src="SSTIGood.java" />
+</example>
+<references>
+<li>Portswigger: <a href="https://portswigger.net/web-security/server-side-template-injection">Server Side Template Injection</a>.</li>
+</references>
+</qhelp>

java/ql/src/experimental/Security/CWE/CWE-094/TemplateInjection.ql → java/ql/src/Security/CWE/CWE-094/TemplateInjection.ql

@@ -1,16 +1,18 @@
 /**
- * @name Server Side Template Injection
- * @description Untrusted input used as a template parameter can lead to remote code execution.
+ * @name Server-side template injection
+ * @description Untrusted input interpreted as a template can lead to remote code execution.
  * @kind path-problem
  * @problem.severity error
+ * @security-severity 9.3
  * @precision high
  * @id java/server-side-template-injection
  * @tags security
+ *       external/cwe/cwe-1336
  *       external/cwe/cwe-094
  */
 
 import java
-import TemplateInjection
+import semmle.code.java.security.TemplateInjectionQuery
 import DataFlow::PathGraph
 
 from TemplateInjectionFlowConfig config, DataFlow::PathNode source, DataFlow::PathNode sink

java/ql/src/change-notes/2022-09-08-server-side-template-injection-query.md

@@ -0,0 +1,4 @@
+---
+category: newQuery
+---
+* The query "Server-side template injection" (`java/server-side-template-injection`) has been promoted from experimental to the main query pack. This query was originally [submitted as an experimental query by @porcupineyhairs](https://github.com/github/codeql/pull/5935).