mirror of
https://github.com/github/codeql.git
synced 2025-12-22 11:46:32 +01:00
Java: Untrusted data used in external APIs
This commit adds two queries for identifying external APIs which are used with untrusted data. These queries are intended to facilitate a security review of the application, and will report any external API which is called with untrusted data. The purpose of this is to: - review how untrusted data flows through this application - identify opportunities to improve taint modeling of sinks and taint steps. As a result this is not suitable for integration into a developer workflow, as it will likely have high false positive rate, but it may help identify false negatives for other queries.
This commit is contained in:
lcartey@github.com
@@ -0,0 +1,8 @@
|
||||
public class XSS extends HttpServlet {
|
||||
protected void doGet(HttpServletRequest request, HttpServletResponse response)
|
||||
throws ServletException, IOException {
|
||||
// BAD: a request parameter is written directly to an error response page
|
||||
response.sendError(HttpServletResponse.SC_NOT_FOUND,
|
||||
"The page \"" + request.getParameter("page") + "\" was not found.");
|
||||
}
|
||||
}
|
||||
@@ -0,0 +1,12 @@
|
||||
public class SQLInjection extends HttpServlet {
|
||||
protected void doGet(HttpServletRequest request, HttpServletResponse response)
|
||||
throws ServletException, IOException {
|
||||
|
||||
StringBuilder sqlQueryBuilder = new StringBuilder();
|
||||
sqlQueryBuilder.append("SELECT * FROM user WHERE user_id='");
|
||||
sqlQueryBuilder.append(request.getParameter("user_id"));
|
||||
sqlQueryBuilder.append("'");
|
||||
|
||||
// ...
|
||||
}
|
||||
}
|
||||
@@ -0,0 +1,48 @@
|
||||
<!DOCTYPE qhelp PUBLIC
|
||||
"-//Semmle//qhelp//EN"
|
||||
"qhelp.dtd">
|
||||
<qhelp>
|
||||
<overview>
|
||||
<p>Using unsanitized untrusted data in an external API can cause a variety of security issues. This query reports
|
||||
all external APIs which are used with untrusted data, along with how frequently the API is used, and how many
|
||||
unique sources of untrusted data flow this API. This query is designed primarily to help identify which APIs
|
||||
may be relevant for security analysis of this application</p>
|
||||
|
||||
<p>An external API is defined as a method call to a method which is not defined in the source code, not overridden
|
||||
in the source code, and is not modeled as a taint step in the default taint library. External APIs may be from the
|
||||
Java standard library, third party dependencies or from internal dependencies. The query will report the method
|
||||
signature with a fully qualified name, along with either <code>[param x]</code>, where <code>x</code> indicates the
|
||||
position of the parameter receiving the untrusted data or <code>[qualifier]</code> indicating the untrusted data is
|
||||
used as the qualifier to the method call.</p>
|
||||
|
||||
</overview>
|
||||
<recommendation>
|
||||
|
||||
<p>For each result:</p>
|
||||
|
||||
<ul>
|
||||
<li>If the result highlights a known sink, no action is required.</li>
|
||||
<li>If the result highlights an unknown sink for a problem, then add modeling for the sink to the relevant query.</li>
|
||||
<li>If the result represents a call to an external API which transfers taint, add the appropriate modeling, and
|
||||
re-run the query to determine what new results have appeared due to this additional modeling.</li>
|
||||
</ul>
|
||||
|
||||
<p>Otherwise, the result is likely uninteresting. Custom versions of this query can extend the <code>SafeExternalAPIMethod</code>
|
||||
class to exclude known safe external APIs from future analysis.
|
||||
|
||||
</recommendation>
|
||||
<example>
|
||||
|
||||
<p>If the query were to return the API <code>javax.servlet.http.HttpServletResponse.sendError(int sc, java.lang.String msg) [param 1]</code>
|
||||
then we should first consider whether this a security relevant sink. In this case, this is writing to a HTTP response, so we should
|
||||
consider whether this is an XSS sink. If it is, we should confirm that it is handled by the XSS query.</p>
|
||||
|
||||
<p>If the query were to return the API <code>java.lang.StringBuilder.append(java.lang.String str) [param 0]</code>, then this should be
|
||||
reviewed as a possible taint step, because tainted data would flow from the 0th argument to the qualifier of the call.</p>
|
||||
|
||||
<p>Note that both examples are correctly handled with the standard taint tracking library and XSS query.</p>
|
||||
</example>
|
||||
<references>
|
||||
|
||||
</references>
|
||||
</qhelp>
|
||||
@@ -0,0 +1,17 @@
|
||||
/**
|
||||
* @name Frequency counts for external APIs which are used with untrusted data
|
||||
* @description This reports the external APIs which are used with untrusted data, along with how
|
||||
* frequently the API is called, and how many unique sources of untrusted data flow
|
||||
* to it.
|
||||
* @id java/count-untrusted-data-external-api
|
||||
* @kind table
|
||||
*/
|
||||
|
||||
import java
|
||||
import semmle.code.java.security.ExternalAPIs::ExternalAPIs
|
||||
import semmle.code.java.dataflow.DataFlow
|
||||
|
||||
from ExternalAPIUsedWithUntrustedData externalAPI
|
||||
select externalAPI, count(externalAPI.getUntrustedDataNode()) as numberOfUses,
|
||||
externalAPI.getNumberOfUntrustedSources() as numberOfUntrustedSources order by
|
||||
numberOfUntrustedSources desc
|
||||
@@ -0,0 +1,59 @@
|
||||
<!DOCTYPE qhelp PUBLIC
|
||||
"-//Semmle//qhelp//EN"
|
||||
"qhelp.dtd">
|
||||
<qhelp>
|
||||
<overview>
|
||||
<p>Using unsanitized untrusted data in an external API can cause a variety of security issues. This query reports
|
||||
all uses of external APIs with untrusted data for review. This query has a deliberately low true positive rate,
|
||||
and is designed to help security reviews for the application, as well as helping identify external APIs that
|
||||
should be modeled as either taint steps, or sinks for specific problems.</p>
|
||||
|
||||
<p>An external API is defined as a method call to a method which is not defined in the source code, not overridden
|
||||
in the source code, and is not modeled as a taint step in the default taint library. External APIs may be from the
|
||||
Java standard library, third party dependencies or from internal dependencies. The query will report uses of
|
||||
untrusted data in either the qualifier or as one of the arguments of external APIs.</p>
|
||||
|
||||
</overview>
|
||||
<recommendation>
|
||||
|
||||
<p>For each result:</p>
|
||||
|
||||
<ul>
|
||||
<li>If the result highlights a known sink, confirm that the result is reported by the relevant query, or
|
||||
that the result is a false positive due to sanitization.</li>
|
||||
<li>If the result highlights an unknown sink for a problem, then add modeling for the sink to the relevant query,
|
||||
and confirm that the result is either found, or is safe due to appropriate sanitization.</li>
|
||||
<li>If the result represents a call to an external API which transfers taint, add the appropriate modeling, and
|
||||
re-run the query to determine what new results have appeared due to this additional modeling.</li>
|
||||
</ul>
|
||||
|
||||
<p>Otherwise, the result is likely uninteresting. Custom versions of this query can extend the <code>SafeExternalAPIMethod</code>
|
||||
class to exclude known safe external APIs from future analysis.
|
||||
|
||||
</recommendation>
|
||||
<example>
|
||||
|
||||
<p>In this first example, a request parameter is read from <code>HttpServletRequest</code> and then ultimately used in a call to the
|
||||
<code>HttpServletResponse.sendError</code> external API:
|
||||
|
||||
<sample src="ExternalAPISinkExample.java" />
|
||||
|
||||
<p>This is an XSS sink. The XSS query should therefore be reviewed to confirm that this sink is appropriately modeled,
|
||||
and if it is, to confirm that the query reports this particular result, or that the result is false positive due to
|
||||
some existing sanitization.</p>
|
||||
|
||||
<p>In this second example, again a request parameter is read from <code>HttpServletRequest</code>.</p>
|
||||
|
||||
<sample src="ExternalAPITaintStepExample.java" />
|
||||
|
||||
<p>If the query reported the call to <code>StringBuilder.append</code> on Line 7, this would suggest that this external API is
|
||||
not currently modeled as a taint step in the taint tracking library. The next step would be to model this as taint step, then
|
||||
re-run the query to determine what additional results might be found. In this example, it seems likely that the result of the
|
||||
<code>StringBuilder</code> will be executed as an SQL query, potentially leading to an SQL injection vulnerability.</p>
|
||||
|
||||
<p>Note that both examples are correctly handled with the standard taint tracking library and XSS query.</p>
|
||||
</example>
|
||||
<references>
|
||||
|
||||
</references>
|
||||
</qhelp>
|
||||
@@ -0,0 +1,21 @@
|
||||
/**
|
||||
* @name Untrusted data passed to external API
|
||||
* @description Data provided remotely is used in this external API.
|
||||
* @id java/untrusted-data-to-external-api
|
||||
* @kind path-problem
|
||||
* @precision very-low
|
||||
* @problem.severity error
|
||||
* @tags security external/cwe/cwe-20
|
||||
*/
|
||||
|
||||
import java
|
||||
import semmle.code.java.dataflow.FlowSources
|
||||
import semmle.code.java.dataflow.TaintTracking
|
||||
import semmle.code.java.security.ExternalAPIs::ExternalAPIs
|
||||
import DataFlow::PathGraph
|
||||
|
||||
from UntrustedDataToExternalAPIConfig config, DataFlow::PathNode source, DataFlow::PathNode sink
|
||||
where config.hasFlowPath(source, sink)
|
||||
select sink, source, sink,
|
||||
"Call to " + sink.getNode().(ExternalAPIDataNode).getMethodDescription() +
|
||||
" with untrusted data from $@.", source, source.toString()
|
||||
146
java/ql/src/semmle/code/java/security/ExternalAPIs.qll
Normal file
146
java/ql/src/semmle/code/java/security/ExternalAPIs.qll
Normal file
@@ -0,0 +1,146 @@
|
||||
/**
|
||||
* Definitions for reasoning about untrusted data used in APIs defined outside the
|
||||
* database.
|
||||
*/
|
||||
|
||||
import java
|
||||
import semmle.code.java.dataflow.FlowSources
|
||||
import semmle.code.java.dataflow.TaintTracking
|
||||
|
||||
module ExternalAPIs {
|
||||
/**
|
||||
* A `Method` which is considered a "safe" external API from a security perspective.
|
||||
*/
|
||||
abstract class SafeExternalAPIMethod extends Method { }
|
||||
|
||||
/** The default set of "safe" external APIs. */
|
||||
class DefaultSafeExternalAPIMethod extends SafeExternalAPIMethod {
|
||||
DefaultSafeExternalAPIMethod() {
|
||||
this instanceof EqualsMethod
|
||||
or
|
||||
getName().regexpMatch("size|length|compareTo|getClass|lastIndexOf")
|
||||
or
|
||||
this.getDeclaringType().hasQualifiedName("org.apache.commons.lang3", "Validate")
|
||||
or
|
||||
getQualifiedName() = "Objects.equals"
|
||||
or
|
||||
getDeclaringType().getQualifiedName() = "java.lang.String" and getName() = "equals"
|
||||
or
|
||||
getDeclaringType().hasQualifiedName("com.google.common.base", "Preconditions")
|
||||
or
|
||||
getDeclaringType().getPackage().getName().matches("org.junit%")
|
||||
or
|
||||
getDeclaringType().hasQualifiedName("com.google.common.base", "Strings") and
|
||||
getName() = "isNullOrEmpty"
|
||||
or
|
||||
getDeclaringType().hasQualifiedName("org.apache.commons.lang3", "StringUtils") and
|
||||
getName() = "isNotEmpty"
|
||||
or
|
||||
getDeclaringType().hasQualifiedName("java.lang", "Character") and
|
||||
getName() = "isDigit"
|
||||
or
|
||||
getDeclaringType().hasQualifiedName("java.lang", "String") and
|
||||
getName().regexpMatch("equalsIgnoreCase|regionMatches")
|
||||
or
|
||||
getDeclaringType().hasQualifiedName("java.lang", "Boolean") and
|
||||
getName() = "parseBoolean"
|
||||
or
|
||||
getDeclaringType().hasQualifiedName("org.apache.commons.io", "IOUtils") and
|
||||
getName() = "closeQuietly"
|
||||
or
|
||||
getDeclaringType().hasQualifiedName("org.springframework.util", "StringUtils") and
|
||||
getName().regexpMatch("hasText|isEmpty")
|
||||
}
|
||||
}
|
||||
|
||||
/** A node representing data being passed to an external API. */
|
||||
class ExternalAPIDataNode extends DataFlow::Node {
|
||||
Call call;
|
||||
int i;
|
||||
|
||||
ExternalAPIDataNode() {
|
||||
(
|
||||
// Argument to call to a method
|
||||
this.asExpr() = call.getArgument(i)
|
||||
or
|
||||
// Qualifier to call to a method which returns non trivial value
|
||||
this.asExpr() = call.getQualifier() and
|
||||
i = -1 and
|
||||
not call.getCallee().getReturnType() instanceof VoidType and
|
||||
not call.getCallee().getReturnType() instanceof BooleanType
|
||||
) and
|
||||
// Defined outside the source archive
|
||||
not call.getCallee().fromSource() and
|
||||
// Not a call to an method which is overridden in source
|
||||
not exists(Method m |
|
||||
m.getASourceOverriddenMethod() = call.getCallee().getSourceDeclaration() and
|
||||
m.fromSource()
|
||||
) and
|
||||
// Not already modelled as a taint step
|
||||
not exists(DataFlow::Node next | TaintTracking::localTaintStep(this, next)) and
|
||||
// Not a call to a known safe external API
|
||||
not call.getCallee() instanceof SafeExternalAPIMethod
|
||||
}
|
||||
|
||||
/** Gets the called API `Method`. */
|
||||
Method getMethod() { result = call.getCallee() }
|
||||
|
||||
/** Gets the index which is passed untrusted data (where -1 indicates the qualifier). */
|
||||
int getIndex() { result = i }
|
||||
|
||||
/** Gets the description of the method being called. */
|
||||
string getMethodDescription() {
|
||||
result =
|
||||
getMethod().getDeclaringType().getPackage() + "." + getMethod().getQualifiedName()
|
||||
}
|
||||
}
|
||||
|
||||
class UntrustedDataToExternalAPIConfig extends TaintTracking::Configuration {
|
||||
UntrustedDataToExternalAPIConfig() { this = "UntrustedDataToExternalAPIConfig" }
|
||||
|
||||
override predicate isSource(DataFlow::Node source) { source instanceof RemoteFlowSource }
|
||||
|
||||
override predicate isSink(DataFlow::Node sink) { sink instanceof ExternalAPIDataNode }
|
||||
}
|
||||
|
||||
/** A node representing untrusted data being passed to an external API. */
|
||||
class UntrustedExternalAPIDataNode extends ExternalAPIDataNode {
|
||||
UntrustedExternalAPIDataNode() { any(UntrustedDataToExternalAPIConfig c).hasFlow(_, this) }
|
||||
|
||||
/** Gets a source of untrusted data which is passed to this external API data node. */
|
||||
DataFlow::Node getAnUntrustedSource() {
|
||||
any(UntrustedDataToExternalAPIConfig c).hasFlow(result, this)
|
||||
}
|
||||
}
|
||||
|
||||
private newtype TExternalAPI =
|
||||
TExternalAPIParameter(Method m, int index) {
|
||||
exists(UntrustedExternalAPIDataNode n |
|
||||
m = n.getMethod() and
|
||||
index = n.getIndex()
|
||||
)
|
||||
}
|
||||
|
||||
/** An external API which is used with untrusted data. */
|
||||
class ExternalAPIUsedWithUntrustedData extends TExternalAPI {
|
||||
/** Gets a possibly untrusted use of this external API. */
|
||||
UntrustedExternalAPIDataNode getUntrustedDataNode() {
|
||||
this = TExternalAPIParameter(result.getMethod(), result.getIndex())
|
||||
}
|
||||
|
||||
/** Gets the number of untrusted sources used with this external API. */
|
||||
int getNumberOfUntrustedSources() {
|
||||
result = count(getUntrustedDataNode().getAnUntrustedSource())
|
||||
}
|
||||
|
||||
string toString() {
|
||||
exists(Method m, int index, string indexString |
|
||||
if index = -1 then indexString = "qualifier" else indexString = "param " + index
|
||||
|
|
||||
this = TExternalAPIParameter(m, index) and
|
||||
result =
|
||||
m.getDeclaringType().(RefType).getQualifiedName() + "." + m.getSignature() + " [" + indexString + "]"
|
||||
)
|
||||
}
|
||||
}
|
||||
}
|
||||
Reference in New Issue
Block a user