initial query

powershell/ql/src/experimental/InjectionHunter/UserInputToDangerousMethod.qhelp

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+<!DOCTYPE qhelp PUBLIC
+  "-//Semmle//qhelp//EN"
+  "qhelp.dtd">
+<qhelp>
+<overview>
+<p>Code that passes user input directly to
+<code>Invoke-Expression</code>, <code>&</code>, or some other library
+routine that executes a command, allows the user to execute malicious
+code.</p>
+
+</overview>
+<recommendation>
+
+<p>Possible script injection risk via the Invoke-Expression cmdlet. Untrusted input can cause arbitrary PowerShell expressions to be run. 
+Variables may be used directly for dynamic parameter arguments, splatting can be used for dynamic parameter names, 
+and the invocation operator can be used for dynamic command names. If content escaping is truly needed, PowerShell has several valid quote characters, 
+so  [System.Management.Automation.Language.CodeGeneration]::Escape* should be used.</p>
+
+</recommendation>
+<example>
+
+<p>The following example shows code that takes a shell script that can be changed
+maliciously by a user, and passes it straight to <code>Invoke-Expression</code>
+without examining it first.</p>
+
+<sample src="examples/command_injection.ps1" />
+
+</example>
+<references>
+
+<li>
+OWASP:
+<a href="https://www.owasp.org/index.php/Command_Injection">Command Injection</a>.
+</li>
+
+<!--  LocalWords:  CWE untrusted unsanitized Runtime
+ -->
+
+</references>
+</qhelp>

powershell/ql/src/experimental/InjectionHunter/UserInputToDangerousMethod.ql

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+/**
+ * @name User Input to Invoke-Expression 
+ * @description Finding cases where the user input is passed an Invoke-Expression command
+ * @kind path-problem
+ * @problem.severity error
+ * @security-severity 9.8
+ * @precision high
+ * @id powershell/microsoft/public/user-input-to-invoke-expression
+ * @tags security
+ *       external/cwe/cwe-078
+ *       external/cwe/cwe-088
+ */
+
+import powershell
+import semmle.code.powershell.dataflow.TaintTracking
+import semmle.code.powershell.dataflow.DataFlow
+import semmle.code.powershell.ApiGraphs
+
+private module TestConfig implements DataFlow::ConfigSig {
+    predicate isSource(DataFlow::Node source) { 
+        exists(CmdCall c | 
+            c.getName() = "Read-Host" and
+            source.asExpr().getExpr() = c) }
+  
+    predicate isSink(DataFlow::Node sink) { sink instanceof Sink }
+    predicate isBarrier(DataFlow::Node node) {node instanceof Sanitizer}
+}
+
+abstract class Source extends DataFlow::Node {}
+
+class ReadHostSource extends Source {
+    ReadHostSource() { 
+        exists(CmdCall c | 
+            this.asExpr().getExpr() = c and
+            c.getName() = "Read-Host" )
+    }   
+}
+
+class GetContentSource extends Source {
+    GetContentSource() { 
+        exists(CmdCall c | 
+            this.asExpr().getExpr() = c and
+            c.getName() = "Get-Content" )
+    }   
+}
+
+class ValueFromPipelineSource extends Source {
+    ValueFromPipelineSource() { 
+        exists(Parameter p |  
+            p.getAnAttribute().toString() = "ValueFromPipeline" and 
+            this.asExpr().getExpr() = p.getAnAccess()   
+        )
+    }   
+}
+
+abstract class Sink extends DataFlow::Node {}
+
+class InvokeExpressionCall extends Sink {
+    InvokeExpressionCall() { 
+        exists(CmdCall c | 
+            this.asExpr().getExpr() = c.getAnArgument() and
+            c.getName() = ["Invoke-Expression", "iex", "Add-Type" ] )
+    }   
+}
+
+class InvokeScriptSink extends Sink {
+    InvokeScriptSink() { 
+        exists(InvokeMemberExpr ie | 
+            this.asExpr().getExpr() = ie.getAnArgument() and
+            ie.getName() = "InvokeScript" and
+            ie.getQualifier().toString() = "InvokeCommand" and
+            ie.getQualifier().getAChild().toString() = "executioncontext"
+        )
+    }
+}
+
+class CreateNestedPipelineSink extends Sink {
+    CreateNestedPipelineSink() { 
+        exists(InvokeMemberExpr ie | 
+            this.asExpr().getExpr() = ie.getAnArgument() and
+            ie.getName() = "CreateNestedPipeline" and
+            ie.getQualifier().toString() = "InvokeCommand" and
+            ie.getQualifier().getAChild().toString() = "executioncontext")
+    }
+}
+
+class AddScriptInvokeSink extends Sink {
+    AddScriptInvokeSink() { 
+        exists(InvokeMemberExpr ie | 
+            this.asExpr().getExpr() = ie.getAnArgument() and
+            ie.getName() = "AddScript" and
+            ie.getQualifier().(InvokeMemberExpr).getName() = "Create" and
+            ie.getQualifier().getAChild().toString() = "PowerShell" and
+            ie.getParent().(InvokeMemberExpr).getName() = "Invoke"
+        )
+    }
+}
+
+abstract class Sanitizer extends DataFlow::Node {}
+
+// class TypedParameterSanitizer extends Sanitizer{
+//     TypedParameterSanitizer() { 
+//         exists(Function f, CmdCall c, Parameter p, Argument a | 
+//             p = f.getAParameter() and
+//             a = c.getAnArgument() and 
+//             p.getName().toLowerCase() = a.getName() and 
+//             p.getStaticType() != "Object" and
+//             c.getName() = f.getName() and 
+            
+//             this.asExpr().getExpr() = a
+//         )
+//     }
+// }
+
+class SingleQuoteSanitizer extends Sanitizer {
+    SingleQuoteSanitizer() { 
+        exists(Expr e, VarReadAccess v | 
+            e = this.asExpr().getExpr().getParent() and
+            e.toString().matches("%'$" + v.getVariable().getName() + "'%")
+        )
+    }
+}
+
+module TestFlow = TaintTracking::Global<TestConfig>;
+import TestFlow::PathGraph
+
+// from TestFlow::PathNode source, TestFlow::PathNode sink
+// where
+//     TestFlow::flowPath(source, sink) and 
+//     sink.getNode().asExpr().getExpr().getLocation().getFile().getBaseName() = "sanitizers.ps1" 
+// select sink.getNode(), source, sink, "Flow from user input to Invoke-Expression"
+
+// from Function f, CmdCall c 
+// where f.getLocation().getFile().getBaseName() = "sanitizers.ps1" 
+// select f, f.getAParameter().getStaticType(), f.getAParameter().getName()
+
+
+//TBD, waiting on mathias on how to connect f and c
+// from Function f, CmdCall c, Parameter p, Argument a
+// where 
+// p = f.getAParameter() and
+// a = c.getAnArgument() and 
+// p.getName().toLowerCase() = a.getName() and 
+// p.getStaticType() != "Object" and
+// c.getName() = f.getName()
+// select a, "argument has a specified static type"
+
+// from Argument a, VarReadAccess v
+// where a.getAChild() = v and 
+// v.getVariable().getName() = "UserInput"
+// select a, v
+
+// from Argument e 
+// where e.getLocation().getFile().getBaseName() = "sanitizers.ps1" 
+// and e.getLocation().getStartLine() = 14
+// select e, e.getAChild(), e.getParent(), e.toString()
+
+
+from Parameter p 
+where p.getLocation().getFile().getBaseName() = "userinput.ps1" 
+// p.getAnAttribute().toString() = "ValueFromPipeline" and 
+
+select p, p.getName()
+
+// from Expr e 
+// where e.getLocation().getFile().getBaseName() = "userinput.ps1"
+// select e, e.getAQlClass()
+
+// from InvokeMemberExpr ie
+// where
+// ie.getLocation().getStartLine() = 28 and ie.getName() = "AddScript"
+// select ie, ie.getName(), ie.getQualifier().toString(), ie.getQualifier().getAChild().toString(), ie.getParent().(InvokeMemberExpr).getName()