Merge pull request #4512 from luchua-bc/sensitive-broadcast

Java: Sensitive broadcast
This commit is contained in:
Anders Schack-Mulligen
2020-11-04 10:47:48 +01:00
committed by GitHub
9 changed files with 474 additions and 6 deletions

View File

@@ -9,21 +9,21 @@
import java
import semmle.code.java.dataflow.TaintTracking
import semmle.code.java.security.SensitiveActions
import DataFlow
import PathGraph
/**
* Gets a regular expression for matching names of variables that indicate the value being held is a credential
* Gets a regular expression for matching names of variables that indicate the value being held may contain sensitive information
*/
private string getACredentialRegex() {
result = "(?i).*challenge|pass(wd|word|code|phrase)(?!.*question).*" or
result = "(?i)(.*username|.*secret|url).*"
}
private string getACredentialRegex() { result = "(?i)(.*username|url).*" }
/** Variable keeps sensitive information judging by its name * */
class CredentialExpr extends Expr {
CredentialExpr() {
exists(Variable v | this = v.getAnAccess() | v.getName().regexpMatch(getACredentialRegex()))
exists(Variable v | this = v.getAnAccess() |
v.getName().regexpMatch([getCommonSensitiveInfoRegex(), getACredentialRegex()])
)
}
}

View File

@@ -0,0 +1,30 @@
public void sendBroadcast1(Context context, String token, String refreshToken)
{
{
// BAD: broadcast sensitive information to all listeners
Intent intent = new Intent();
intent.setAction("com.example.custom_action");
intent.putExtra("token", token);
intent.putExtra("refreshToken", refreshToken);
context.sendBroadcast(intent);
}
{
// GOOD: broadcast sensitive information only to those with permission
Intent intent = new Intent();
intent.setAction("com.example.custom_action");
intent.putExtra("token", token);
intent.putExtra("refreshToken", refreshToken);
context.sendBroadcast(intent, "com.example.user_permission");
}
{
// GOOD: broadcast sensitive information to a specific application
Intent intent = new Intent();
intent.setAction("com.example.custom_action");
intent.setClassName("com.example2", "com.example2.UserInfoHandler");
intent.putExtra("token", token);
intent.putExtra("refreshToken", refreshToken);
context.sendBroadcast(intent);
}
}

View File

@@ -0,0 +1,50 @@
<!DOCTYPE qhelp PUBLIC "-//Semmle//qhelp//EN" "qhelp.dtd">
<qhelp>
<overview>
<p>Broadcast intents in an Android application are visible to all applications installed on the same mobile device, exposing all sensitive information they contain.</p>
<p>Broadcasts are vulnerable to passive eavesdropping or active denial of service attacks when an intent is broadcast without specifying any receiver permission or receiver application.</p>
</overview>
<recommendation>
<p>
Specify a receiver permission or application when broadcasting intents, or switch to
<code>LocalBroadcastManager</code>
or the latest
<code>LiveData</code>
library.
</p>
</recommendation>
<example>
<p>The following example shows two ways of broadcasting intents. In the 'BAD' case, no "receiver permission" is specified. In the 'GOOD' case, "receiver permission" or "receiver application" is specified.</p>
<sample src="SensitiveBroadcast.java" />
</example>
<references>
<li>
CWE:
<a href="https://cwe.mitre.org/data/definitions/927.html">CWE-927: Use of Implicit Intent for Sensitive Communication</a>
</li>
<li>
Android Developers:
<a href="https://developer.android.com/guide/components/broadcasts">Security considerations and best practices for sending and receiving broadcasts</a>
</li>
<li>
SonarSource:
<a href="https://rules.sonarsource.com/java/type/Security%20Hotspot/RSPEC-5320">Broadcasting intents is security-sensitive</a>
</li>
<li>
Android Developer Fundamentals:
<a href="https://google-developer-training.github.io/android-developer-fundamentals-course-concepts-v2/unit-3-working-in-the-background/lesson-7-background-tasks/7-3-c-broadcasts/7-3-c-broadcasts.html">Restricting broadcasts</a>
</li>
<li>
Carnegie Mellon University:
<a href="https://wiki.sei.cmu.edu/confluence/display/android/DRD03-J.+Do+not+broadcast+sensitive+information+using+an+implicit+intent">DRD03-J. Do not broadcast sensitive information using an implicit intent</a>
</li>
<li>
Android Developers:
<a href="https://developer.android.com/topic/libraries/architecture/livedata">Android LiveData Overview</a>
</li>
</references>
</qhelp>

View File

@@ -0,0 +1,171 @@
/**
* @name Broadcasting sensitive data to all Android applications
* @id java/sensitive-broadcast
* @description An Android application uses implicit intents to broadcast sensitive data to all applications without specifying any receiver permission.
* @kind path-problem
* @tags security
* external/cwe-927
*/
import java
import semmle.code.java.dataflow.DataFlow3
import semmle.code.java.dataflow.TaintTracking
import semmle.code.java.frameworks.android.Intent
import semmle.code.java.security.SensitiveActions
import DataFlow::PathGraph
/**
* Gets regular expression for matching names of Android variables that indicate the value being held contains sensitive information.
*/
private string getAndroidSensitiveInfoRegex() { result = "(?i).*(email|phone|ticket).*" }
/**
* Method call to pass information to the `Intent` object.
*/
class PutIntentExtraMethodAccess extends MethodAccess {
PutIntentExtraMethodAccess() {
(
getMethod().getName().matches("put%Extra") or
getMethod().hasName("putExtras")
) and
getMethod().getDeclaringType() instanceof TypeIntent
}
}
/**
* Method call to pass information to the intent extra bundle object.
*/
class PutBundleExtraMethodAccess extends MethodAccess {
PutBundleExtraMethodAccess() {
getMethod().getName().regexpMatch("put\\w+") and
getMethod().getDeclaringType().getASupertype*().hasQualifiedName("android.os", "BaseBundle")
}
}
/** Finds variables that hold sensitive information judging by their names. */
class SensitiveInfoExpr extends Expr {
SensitiveInfoExpr() {
exists(Variable v | this = v.getAnAccess() |
v.getName().regexpMatch([getCommonSensitiveInfoRegex(), getAndroidSensitiveInfoRegex()])
)
}
}
/**
* A method access of the `Context.sendBroadcast` family.
*/
class SendBroadcastMethodAccess extends MethodAccess {
SendBroadcastMethodAccess() {
this.getMethod().getDeclaringType() instanceof TypeContext and
this.getMethod().getName().matches("send%Broadcast%")
}
}
private class NullArgFlowConfig extends DataFlow2::Configuration {
NullArgFlowConfig() { this = "Flow configuration with a null argument" }
override predicate isSource(DataFlow::Node src) { src.asExpr() instanceof NullLiteral }
override predicate isSink(DataFlow::Node sink) {
exists(SendBroadcastMethodAccess ma | sink.asExpr() = ma.getAnArgument())
}
}
private class EmptyArrayArgFlowConfig extends DataFlow3::Configuration {
EmptyArrayArgFlowConfig() { this = "Flow configuration with an empty array argument" }
override predicate isSource(DataFlow::Node src) {
src.asExpr().(ArrayCreationExpr).getFirstDimensionSize() = 0
}
override predicate isSink(DataFlow::Node sink) {
exists(SendBroadcastMethodAccess ma | sink.asExpr() = ma.getAnArgument())
}
}
/**
* Holds if a `sendBroadcast` call doesn't specify receiver permission.
*/
predicate isSensitiveBroadcastSink(DataFlow::Node sink) {
exists(SendBroadcastMethodAccess ma |
sink.asExpr() = ma.getAnArgument() and
(
ma.getMethod().hasName("sendBroadcast") and
(
ma.getNumArgument() = 1 // sendBroadcast(Intent intent)
or
// sendBroadcast(Intent intent, String receiverPermission)
exists(NullArgFlowConfig conf | conf.hasFlow(_, DataFlow::exprNode(ma.getArgument(1))))
)
or
ma.getMethod().hasName("sendBroadcastAsUser") and
(
ma.getNumArgument() = 2 or // sendBroadcastAsUser(Intent intent, UserHandle user)
exists(NullArgFlowConfig conf | conf.hasFlow(_, DataFlow::exprNode(ma.getArgument(2)))) // sendBroadcastAsUser(Intent intent, UserHandle user, String receiverPermission)
)
or
ma.getMethod().hasName("sendBroadcastWithMultiplePermissions") and
exists(EmptyArrayArgFlowConfig config |
config.hasFlow(_, DataFlow::exprNode(ma.getArgument(1))) // sendBroadcastWithMultiplePermissions(Intent intent, String[] receiverPermissions)
)
or
// Method calls of `sendOrderedBroadcast` whose second argument is always `receiverPermission`
ma.getMethod().hasName("sendOrderedBroadcast") and
(
// sendOrderedBroadcast(Intent intent, String receiverPermission) or sendOrderedBroadcast(Intent intent, String receiverPermission, BroadcastReceiver resultReceiver, Handler scheduler, int initialCode, String initialData, Bundle initialExtras)
exists(NullArgFlowConfig conf | conf.hasFlow(_, DataFlow::exprNode(ma.getArgument(1)))) and
ma.getNumArgument() <= 7
or
// sendOrderedBroadcast(Intent intent, String receiverPermission, String receiverAppOp, BroadcastReceiver resultReceiver, Handler scheduler, int initialCode, String initialData, Bundle initialExtras)
exists(NullArgFlowConfig conf | conf.hasFlow(_, DataFlow::exprNode(ma.getArgument(1)))) and
exists(NullArgFlowConfig conf | conf.hasFlow(_, DataFlow::exprNode(ma.getArgument(2)))) and
ma.getNumArgument() = 8
)
or
// Method call of `sendOrderedBroadcastAsUser(Intent intent, UserHandle user, String receiverPermission, BroadcastReceiver resultReceiver, Handler scheduler, int initialCode, String initialData, Bundle initialExtras)`
ma.getMethod().hasName("sendOrderedBroadcastAsUser") and
exists(NullArgFlowConfig conf | conf.hasFlow(_, DataFlow::exprNode(ma.getArgument(2))))
)
)
}
/**
* Taint configuration tracking flow from variables containing sensitive information to broadcast intents.
*/
class SensitiveBroadcastConfig extends TaintTracking::Configuration {
SensitiveBroadcastConfig() { this = "Sensitive Broadcast Configuration" }
override predicate isSource(DataFlow::Node source) {
source.asExpr() instanceof SensitiveInfoExpr
}
override predicate isSink(DataFlow::Node sink) { isSensitiveBroadcastSink(sink) }
/**
* Holds if there is an additional flow step from `PutIntentExtraMethodAccess` or `PutBundleExtraMethodAccess` that taints the `Intent` or its extras `Bundle`.
*/
override predicate isAdditionalTaintStep(DataFlow::Node node1, DataFlow::Node node2) {
exists(PutIntentExtraMethodAccess pia |
node1.asExpr() = pia.getAnArgument() and node2.asExpr() = pia.getQualifier()
)
or
exists(PutBundleExtraMethodAccess pba |
node1.asExpr() = pba.getAnArgument() and node2.asExpr() = pba.getQualifier()
)
}
/**
* Holds if broadcast doesn't specify receiving package name of the 3rd party app
*/
override predicate isSanitizer(DataFlow::Node node) {
exists(MethodAccess setReceiverMa |
setReceiverMa.getMethod().hasName(["setPackage", "setClass", "setClassName", "setComponent"]) and
setReceiverMa.getQualifier().(VarAccess).getVariable().getAnAccess() = node.asExpr()
)
}
}
from SensitiveBroadcastConfig cfg, DataFlow::PathNode source, DataFlow::PathNode sink
where cfg.hasFlowPath(source, sink)
select sink.getNode(), source, sink, "Sending $@ to broadcast.", source.getNode(),
"sensitive information"

View File

@@ -27,6 +27,14 @@ private string nonSuspicious() {
result = "%crypt%"
}
/**
* Gets a regular expression for matching common names of variables that indicate the value being held contains sensitive information.
*/
string getCommonSensitiveInfoRegex() {
result = "(?i).*challenge|pass(wd|word|code|phrase)(?!.*question).*" or
result = "(?i).*(token|secret).*"
}
/** An expression that might contain sensitive data. */
abstract class SensitiveExpr extends Expr { }

View File

@@ -0,0 +1,34 @@
edges
| SensitiveBroadcast.java:12:34:12:38 | token : String | SensitiveBroadcast.java:14:31:14:36 | intent |
| SensitiveBroadcast.java:13:41:13:52 | refreshToken : String | SensitiveBroadcast.java:14:31:14:36 | intent |
| SensitiveBroadcast.java:25:32:25:39 | password : String | SensitiveBroadcast.java:26:31:26:36 | intent |
| SensitiveBroadcast.java:36:35:36:39 | email : String | SensitiveBroadcast.java:38:31:38:36 | intent |
| SensitiveBroadcast.java:50:22:50:29 | password : String | SensitiveBroadcast.java:52:31:52:36 | intent |
| SensitiveBroadcast.java:97:35:97:40 | ticket : String | SensitiveBroadcast.java:98:54:98:59 | intent |
| SensitiveBroadcast.java:109:32:109:39 | passcode : String | SensitiveBroadcast.java:111:54:111:59 | intent |
| SensitiveBroadcast.java:136:33:136:38 | passwd : String | SensitiveBroadcast.java:140:54:140:59 | intent |
nodes
| SensitiveBroadcast.java:12:34:12:38 | token : String | semmle.label | token : String |
| SensitiveBroadcast.java:13:41:13:52 | refreshToken : String | semmle.label | refreshToken : String |
| SensitiveBroadcast.java:14:31:14:36 | intent | semmle.label | intent |
| SensitiveBroadcast.java:25:32:25:39 | password : String | semmle.label | password : String |
| SensitiveBroadcast.java:26:31:26:36 | intent | semmle.label | intent |
| SensitiveBroadcast.java:36:35:36:39 | email : String | semmle.label | email : String |
| SensitiveBroadcast.java:38:31:38:36 | intent | semmle.label | intent |
| SensitiveBroadcast.java:50:22:50:29 | password : String | semmle.label | password : String |
| SensitiveBroadcast.java:52:31:52:36 | intent | semmle.label | intent |
| SensitiveBroadcast.java:97:35:97:40 | ticket : String | semmle.label | ticket : String |
| SensitiveBroadcast.java:98:54:98:59 | intent | semmle.label | intent |
| SensitiveBroadcast.java:109:32:109:39 | passcode : String | semmle.label | passcode : String |
| SensitiveBroadcast.java:111:54:111:59 | intent | semmle.label | intent |
| SensitiveBroadcast.java:136:33:136:38 | passwd : String | semmle.label | passwd : String |
| SensitiveBroadcast.java:140:54:140:59 | intent | semmle.label | intent |
#select
| SensitiveBroadcast.java:14:31:14:36 | intent | SensitiveBroadcast.java:12:34:12:38 | token : String | SensitiveBroadcast.java:14:31:14:36 | intent | Sending $@ to broadcast. | SensitiveBroadcast.java:12:34:12:38 | token | sensitive information |
| SensitiveBroadcast.java:14:31:14:36 | intent | SensitiveBroadcast.java:13:41:13:52 | refreshToken : String | SensitiveBroadcast.java:14:31:14:36 | intent | Sending $@ to broadcast. | SensitiveBroadcast.java:13:41:13:52 | refreshToken | sensitive information |
| SensitiveBroadcast.java:26:31:26:36 | intent | SensitiveBroadcast.java:25:32:25:39 | password : String | SensitiveBroadcast.java:26:31:26:36 | intent | Sending $@ to broadcast. | SensitiveBroadcast.java:25:32:25:39 | password | sensitive information |
| SensitiveBroadcast.java:38:31:38:36 | intent | SensitiveBroadcast.java:36:35:36:39 | email : String | SensitiveBroadcast.java:38:31:38:36 | intent | Sending $@ to broadcast. | SensitiveBroadcast.java:36:35:36:39 | email | sensitive information |
| SensitiveBroadcast.java:52:31:52:36 | intent | SensitiveBroadcast.java:50:22:50:29 | password : String | SensitiveBroadcast.java:52:31:52:36 | intent | Sending $@ to broadcast. | SensitiveBroadcast.java:50:22:50:29 | password | sensitive information |
| SensitiveBroadcast.java:98:54:98:59 | intent | SensitiveBroadcast.java:97:35:97:40 | ticket : String | SensitiveBroadcast.java:98:54:98:59 | intent | Sending $@ to broadcast. | SensitiveBroadcast.java:97:35:97:40 | ticket | sensitive information |
| SensitiveBroadcast.java:111:54:111:59 | intent | SensitiveBroadcast.java:109:32:109:39 | passcode : String | SensitiveBroadcast.java:111:54:111:59 | intent | Sending $@ to broadcast. | SensitiveBroadcast.java:109:32:109:39 | passcode | sensitive information |
| SensitiveBroadcast.java:140:54:140:59 | intent | SensitiveBroadcast.java:136:33:136:38 | passwd : String | SensitiveBroadcast.java:140:54:140:59 | intent | Sending $@ to broadcast. | SensitiveBroadcast.java:136:33:136:38 | passwd | sensitive information |

View File

@@ -0,0 +1,173 @@
import android.content.Context;
import android.content.Intent;
import android.os.Bundle;
import java.util.ArrayList;
class SensitiveBroadcast {
// BAD - Tests broadcast of access token with intent extra.
public void sendBroadcast1(Context context, String token, String refreshToken) {
Intent intent = new Intent();
intent.setAction("com.example.custom_action");
intent.putExtra("token", token);
intent.putExtra("refreshToken", refreshToken);
context.sendBroadcast(intent);
}
// BAD - Tests broadcast of sensitive user information with intent extra.
public void sendBroadcast2(Context context) {
String userName = "test123";
String password = "abc12345";
Intent intent = new Intent();
intent.setAction("com.example.custom_action");
intent.putExtra("name", userName);
intent.putExtra("pwd", password);
context.sendBroadcast(intent);
}
// BAD - Tests broadcast of email information with extra bundle.
public void sendBroadcast3(Context context) {
String email = "user123@example.com";
Intent intent = new Intent();
intent.setAction("com.example.custom_action");
Bundle bundle = new Bundle();
bundle.putString("email", email);
intent.putExtras(bundle);
context.sendBroadcast(intent);
}
// BAD - Tests broadcast of sensitive user information with null permission.
public void sendBroadcast4(Context context) {
String username = "test123";
String password = "abc12345";
Intent intent = new Intent();
intent.setAction("com.example.custom_action");
ArrayList<String> userinfo = new ArrayList<String>();
userinfo.add(username);
userinfo.add(password);
intent.putStringArrayListExtra("userinfo", userinfo);
context.sendBroadcast(intent, null);
}
// GOOD - Tests broadcast of sensitive user information with permission using string literal.
public void sendBroadcast5(Context context) {
String username = "test123";
String password = "abc12345";
Intent intent = new Intent();
intent.setAction("com.example.custom_action");
intent.putExtra("name", username);
intent.putExtra("pwd", password);
context.sendBroadcast(intent, "com.example.user_permission");
}
// GOOD - Tests broadcast of access ticket with permission using string object.
public void sendBroadcast6(Context context) {
String ticket = "Tk9UIFNlY3VyZSBUaWNrZXQ=";
Intent intent = new Intent();
intent.setAction("com.example.custom_action");
intent.putExtra("ticket", ticket);
String perm = "com.example.user_permission";
context.sendBroadcast(intent, perm);
}
// GOOD - Tests broadcast of sensitive user information to a specific application.
public void sendBroadcast7(Context context) {
String username = "test123";
String password = "abc12345";
Intent intent = new Intent();
intent.setAction("com.example.custom_action");
intent.setClassName("com.example2", "com.example2.UserInfoHandler");
intent.putExtra("name", username);
intent.putExtra("pwd", password);
context.sendBroadcast(intent);
}
// BAD - Tests broadcast of access ticket with multiple permissions using direct empty array initialization.
public void sendBroadcast8(Context context) {
String ticket = "Tk9UIFNlY3VyZSBUaWNrZXQ=";
Intent intent = new Intent();
intent.setAction("com.example.custom_action");
intent.putExtra("ticket", ticket);
context.sendBroadcastWithMultiplePermissions(intent, new String[]{});
}
// BAD - Tests broadcast of sensitive user information with multiple permissions using empty array initialization through a variable.
public void sendBroadcast9(Context context) {
String username = "test123";
String passcode = "abc12345";
Intent intent = new Intent();
intent.setAction("com.example.custom_action");
intent.putExtra("name", username);
intent.putExtra("pwd", passcode);
String[] perms = new String[0];
context.sendBroadcastWithMultiplePermissions(intent, perms);
}
// GOOD - Tests broadcast of sensitive user information with multiple permissions.
public void sendBroadcast10(Context context) {
String username = "test123";
String password = "abc12345";
Intent intent = new Intent();
intent.setAction("com.example.custom_action");
intent.putExtra("name", username);
intent.putExtra("pwd", password);
String[] perms = new String[]{"com.example.custom_action", "com.example.custom_action2"};
context.sendBroadcastWithMultiplePermissions(intent, perms);
}
// BAD - Tests broadcast of sensitive user information with multiple permissions using empty array initialization through two variables and `intent.putExtras(bundle)`.
public void sendBroadcast11(Context context) {
String username = "test123";
String passwd = "abc12345";
Intent intent = new Intent();
intent.setAction("com.example.custom_action");
Bundle bundle = new Bundle();
bundle.putString("name", username);
bundle.putString("pwd", passwd);
intent.putExtras(bundle);
String[] perms = new String[0];
String[] perms2 = perms;
context.sendBroadcastWithMultiplePermissions(intent, perms2);
}
/**
* BAD - Tests broadcast of sensitive user information with multiple permissions using empty array initialization through two variables and `intent.getExtras().putString()`.
* Note this case of `getExtras().putString(...)` is not yet detected thus is beyond what the query is capable of.
*/
public void sendBroadcast12(Context context) {
String username = "test123";
String password = "abc12345";
Intent intent = new Intent();
intent.setAction("com.example.custom_action");
Bundle bundle = new Bundle();
intent.putExtras(bundle);
intent.getExtras().putString("name", username);
intent.getExtras().putString("pwd", password);
String[] perms = new String[0];
String[] perms2 = perms;
context.sendBroadcastWithMultiplePermissions(intent, perms2);
}
// GOOD - Tests broadcast of sensitive user information with ordered broadcast.
public void sendBroadcast13(Context context) {
String username = "test123";
String password = "abc12345";
Intent intent = new Intent();
intent.setAction("com.example.custom_action");
intent.putExtra("name", username);
intent.putExtra("pwd", password);
context.sendOrderedBroadcast(intent, "com.example.USER_PERM");
}
}

View File

@@ -0,0 +1 @@
experimental/Security/CWE/CWE-927/SensitiveBroadcast.ql

View File

@@ -0,0 +1 @@
// semmle-extractor-options: --javac-args -cp ${testdir}/../../../../stubs/google-android-9.0.0