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Merge pull request #13608 from egregius313/egregius313/weak-randomness
Java: Add Weak Randomness Query (CWE-330/338)
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‎java/ql/lib/ext/java.security.spec.model.yml

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@@ -3,6 +3,11 @@ extensions:
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pack: codeql/java-all
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extensible: sinkModel
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data:
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- ["java.security.spec", "DSAPrivateKeySpec", False, "DSAPrivateKeySpec", "", "", "Argument[0..3]", "credentials-key", "manual"]
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- ["java.security.spec", "ECPrivateKeySpec", False, "ECPrivateKeySpec", "", "", "Argument[0]", "credentials-key", "manual"]
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- ["java.security.spec", "EncodedKeySpec", False, "EncodedKeySpec", "(byte[])", "", "Argument[0]", "credentials-key", "hq-generated"]
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- ["java.security.spec", "PKCS8EncodedKeySpec", False, "PKCS8EncodedKeySpec", "(byte[])", "", "Argument[0]", "credentials-key", "hq-generated"]
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- ["java.security.spec", "RSAMultiPrimePrivateCrtKeySpec", False, "RSAMultiPrimePrivateCrtKeySpec", "", "", "Argument[2]", "credentials-key", "manual"]
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- ["java.security.spec", "RSAPrivateCrtKeySpec", False, "RSAPrivateCrtKeySpec", "", "", "Argument[2]", "credentials-key", "manual"]
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- ["java.security.spec", "RSAPrivateKeySpec", False, "RSAPrivateKeySpec", "", "", "Argument[1]", "credentials-key", "manual"]
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- ["java.security.spec", "X509EncodedKeySpec", False, "X509EncodedKeySpec", "(byte[])", "", "Argument[0]", "credentials-key", "hq-generated"]

‎java/ql/lib/ext/javax.crypto.spec.model.yml

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@@ -11,15 +11,18 @@ extensions:
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pack: codeql/java-all
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extensible: sinkModel
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data:
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- ["javax.crypto.spec", "PBEKeySpec", False, "PBEKeySpec", "(char[])", "", "Argument[0]", "credentials-password", "hq-generated"]
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- ["javax.crypto.spec", "PBEKeySpec", False, "PBEKeySpec", "(char[],byte[],int)", "", "Argument[0]", "credentials-password", "hq-generated"]
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- ["javax.crypto.spec", "PBEKeySpec", False, "PBEKeySpec", "(char[],byte[],int,int)", "", "Argument[0]", "credentials-password", "hq-generated"]
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- ["javax.crypto.spec", "DESKeySpec", False, "DESKeySpec", "(byte[])", "", "Argument[0]", "credentials-key", "hq-generated"]
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- ["javax.crypto.spec", "DESKeySpec", False, "DESKeySpec", "(byte[],int)", "", "Argument[0]", "credentials-key", "hq-generated"]
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- ["javax.crypto.spec", "DESKeySpec", False, "isParityAdjusted", "(byte[],int)", "", "Argument[0]", "credentials-key", "hq-generated"]
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- ["javax.crypto.spec", "DESKeySpec", False, "isWeak", "(byte[],int)", "", "Argument[0]", "credentials-key", "hq-generated"]
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- ["javax.crypto.spec", "DESedeKeySpec", False, "DESedeKeySpec", "(byte[])", "", "Argument[0]", "credentials-key", "hq-generated"]
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- ["javax.crypto.spec", "DESedeKeySpec", False, "DESedeKeySpec", "(byte[],int)", "", "Argument[0]", "credentials-key", "hq-generated"]
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- ["javax.crypto.spec", "DESedeKeySpec", False, "isParityAdjusted", "(byte[],int)", "", "Argument[0]", "credentials-key", "hq-generated"]
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- ["javax.crypto.spec", "DHPrivateKeySpec", False, "DHPrivateKeySpec", "", "", "Argument[0]", "credentials-key", "manual"]
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- ["javax.crypto.spec", "PBEKeySpec", False, "PBEKeySpec", "", "", "Argument[1]", "encryption-salt", "manual"]
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- ["javax.crypto.spec", "PBEKeySpec", False, "PBEKeySpec", "(char[])", "", "Argument[0]", "credentials-password", "hq-generated"]
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- ["javax.crypto.spec", "PBEKeySpec", False, "PBEKeySpec", "(char[],byte[],int)", "", "Argument[0]", "credentials-password", "hq-generated"]
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- ["javax.crypto.spec", "PBEKeySpec", False, "PBEKeySpec", "(char[],byte[],int,int)", "", "Argument[0]", "credentials-password", "hq-generated"]
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- ["javax.crypto.spec", "PBEParameterSpec", False, "PBEParameterSpec", "", "", "Argument[0]", "encryption-salt", "manual"]
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- ["javax.crypto.spec", "SecretKeySpec", False, "SecretKeySpec", "(byte[],String)", "", "Argument[0]", "credentials-key", "hq-generated"]
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- ["javax.crypto.spec", "SecretKeySpec", False, "SecretKeySpec", "(byte[],int,int,String)", "", "Argument[0]", "credentials-key", "hq-generated"]

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

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/** Provides classes and predicates for reasoning about insecure randomness. */
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import java
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private import semmle.code.java.frameworks.Servlets
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private import semmle.code.java.security.SensitiveActions
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private import semmle.code.java.security.SensitiveApi
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private import semmle.code.java.dataflow.TaintTracking
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private import semmle.code.java.dataflow.ExternalFlow
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private import semmle.code.java.security.RandomQuery
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/**
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* A node representing a source of insecure randomness.
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*
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* For example, use of `java.util.Random` or `java.lang.Math.random`.
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*/
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abstract class InsecureRandomnessSource extends DataFlow::Node { }
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private class RandomMethodSource extends InsecureRandomnessSource {
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RandomMethodSource() {
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exists(RandomDataSource s | this.asExpr() = s.getOutput() |
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not s.getQualifier().getType() instanceof SafeRandomImplementation
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)
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}
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}
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/**
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* A type which is an implementation of `java.util.Random` but considered to be safe.
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*
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* For example, `java.security.SecureRandom`.
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*/
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abstract private class SafeRandomImplementation extends RefType { }
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private class TypeSecureRandom extends SafeRandomImplementation instanceof SecureRandomNumberGenerator
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{ }
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private class TypeHadoopOsSecureRandom extends SafeRandomImplementation {
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TypeHadoopOsSecureRandom() {
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this.hasQualifiedName("org.apache.hadoop.crypto.random", "OsSecureRandom")
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}
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}
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/**
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* A node representing an operation which should not use a Insecurely random value.
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*/
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abstract class InsecureRandomnessSink extends DataFlow::Node { }
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/**
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* A node which sets the value of a cookie.
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*/
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private class CookieSink extends InsecureRandomnessSink {
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CookieSink() {
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exists(Call c |
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c.(ClassInstanceExpr).getConstructedType() instanceof TypeCookie and
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this.asExpr() = c.getArgument(1)
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or
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c.(MethodCall).getMethod().getDeclaringType() instanceof TypeCookie and
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c.(MethodCall).getMethod().hasName("setValue") and
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this.asExpr() = c.getArgument(0)
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)
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}
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}
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private class SensitiveActionSink extends InsecureRandomnessSink {
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SensitiveActionSink() { this.asExpr() instanceof SensitiveExpr }
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}
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private class CredentialsSink extends InsecureRandomnessSink instanceof CredentialsSinkNode { }
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/**
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* A taint-tracking configuration for Insecure randomness.
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*/
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module InsecureRandomnessConfig implements DataFlow::ConfigSig {
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predicate isSource(DataFlow::Node src) { src instanceof InsecureRandomnessSource }
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predicate isSink(DataFlow::Node sink) { sink instanceof InsecureRandomnessSink }
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predicate isBarrierIn(DataFlow::Node n) { isSource(n) }
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predicate isAdditionalFlowStep(DataFlow::Node n1, DataFlow::Node n2) {
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n1.asExpr() = n2.asExpr().(BinaryExpr).getAnOperand()
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or
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n1.asExpr() = n2.asExpr().(UnaryExpr).getExpr()
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or
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exists(MethodCall mc, string methodName |
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mc.getMethod().hasQualifiedName("org.owasp.esapi", "Encoder", methodName) and
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methodName.matches("encode%")
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|
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n1.asExpr() = mc.getArgument(0) and
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n2.asExpr() = mc
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)
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}
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}
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/**
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* Taint-tracking flow of a Insecurely random value into a sensitive sink.
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*/
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module InsecureRandomnessFlow = TaintTracking::Global<InsecureRandomnessConfig>;

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

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}
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}
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/**
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* A method access calling the `random` of `java.lang.Math`.
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*/
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class MathRandomSource extends RandomDataSource {
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MathRandomSource() { this.getMethod().hasQualifiedName("java.lang", "Math", "random") }
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override Expr getOutput() { result = this }
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}
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/**
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* A method access calling a method declared on `org.apache.commons.lang3.RandomUtils`
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* that returns random data or writes random data to an argument.
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override Expr getOutput() { result = this }
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}
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/**
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* A method access calling a method declared on `org.apache.commons.lang3.RandomStringUtils`
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*/
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class ApacheCommonsRandomStringSource extends RandomDataSource {
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ApacheCommonsRandomStringSource() {
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exists(Method m | m = this.getMethod() |
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m.getName().matches("random%") and
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m.getDeclaringType()
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.hasQualifiedName(["org.apache.commons.lang3", "org.apache.commons.lang"],
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"RandomStringUtils")
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)
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}
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override Expr getOutput() { result = this }
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}

‎java/ql/src/Security/CWE/CWE-330/InsecureRandomness.qhelp

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<!DOCTYPE qhelp PUBLIC
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"-//Semmle//qhelp//EN"
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"qhelp.dtd">
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<qhelp>
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<overview>
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<p>
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If you use a cryptographically weak pseudo-random number generator to generate security-sensitive values,
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such as passwords, attackers can more easily predict those values.
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</p>
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<p>
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Pseudo-random number generators generate a sequence of numbers that only approximates the properties
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of random numbers. The sequence is not truly random because it is completely determined by a
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relatively small set of initial values (the seed). If the random number generator is
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cryptographically weak, then this sequence may be easily predictable through outside observations.
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</p>
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</overview>
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<recommendation>
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<p>
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The <code>java.util.Random</code> random number generator is not cryptographically secure. Use a secure random number generator such as <code>java.security.SecureRandom</code> instead.
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</p>
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<p>
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Use a cryptographically secure pseudo-random number generator if the output is to be used in a
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security-sensitive context. As a general rule, a value should be considered "security-sensitive"
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if predicting it would allow the attacker to perform an action that they would otherwise be unable
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to perform. For example, if an attacker could predict the random password generated for a new user,
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they would be able to log in as that new user.
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</p>
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</recommendation>
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<example>
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<p>
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The following examples show different ways of generating a cookie with a random value.
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</p>
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<p>
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In the first (BAD) case, we generate a fresh cookie by appending a random integer to the end of a static
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string. The random number generator used (<code>Random</code>) is not cryptographically secure,
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so it may be possible for an attacker to predict the generated cookie.
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</p>
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<sample src="examples/InsecureRandomnessCookie.java" />
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<p>
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In the second (GOOD) case, we generate a fresh cookie by appending a random integer to the end of a static
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string. The random number generator used (<code>SecureRandom</code>) is cryptographically secure,
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so it is not possible for an attacker to predict the generated cookie.
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</p>
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<sample src="examples/SecureRandomnessCookie.java" />
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</example>
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<references>
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<li>Wikipedia: <a href="http://en.wikipedia.org/wiki/Pseudorandom_number_generator">Pseudo-random number generator</a>.</li>
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<li>
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Java Docs: <a href="http://docs.oracle.com/javase/8/docs/api/java/util/Random.html">Random</a>.
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</li>
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<li>
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Java Docs: <a href="http://docs.oracle.com/javase/8/docs/api/java/security/SecureRandom.html">SecureRandom</a>.
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</li>
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</references>
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</qhelp>

‎java/ql/src/Security/CWE/CWE-330/InsecureRandomness.ql

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/**
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* @name Insecure randomness
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* @description Using a cryptographically Insecure pseudo-random number generator to generate a
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* security-sensitive value may allow an attacker to predict what value will
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* be generated.
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* @kind path-problem
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* @problem.severity warning
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* @security-severity 7.8
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* @precision high
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* @id java/insecure-randomness
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* @tags security
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* external/cwe/cwe-330
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* external/cwe/cwe-338
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*/
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import java
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import semmle.code.java.security.InsecureRandomnessQuery
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import InsecureRandomnessFlow::PathGraph
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from InsecureRandomnessFlow::PathNode source, InsecureRandomnessFlow::PathNode sink
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where InsecureRandomnessFlow::flowPath(source, sink)
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select sink.getNode(), source, sink, "Potential Insecure randomness due to a $@.", source.getNode(),
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"Insecure randomness source."

‎java/ql/src/Security/CWE/CWE-330/examples/InsecureRandomnessCookie.java

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Random r = new Random();
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byte[] bytes = new byte[16];
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r.nextBytes(bytes);
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String cookieValue = encode(bytes);
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Cookie cookie = new Cookie("name", cookieValue);
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response.addCookie(cookie);

‎java/ql/src/Security/CWE/CWE-330/examples/SecureRandomnessCookie.java

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SecureRandom r = new SecureRandom();
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byte[] bytes = new byte[16];
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r.nextBytes(bytes);
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String cookieValue = encode(bytes);
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Cookie cookie = new Cookie("name", cookieValue);
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response.addCookie(cookie);

‎java/ql/src/change-notes/2023-11-08-weak-randomness-query.md

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---
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category: newQuery
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---
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* Added the `java/insecure-randomness` query to detect uses of weakly random values which an attacker may be able to predict. Also added the `crypto-parameter` sink kind for sinks which represent the parameters and keys of cryptographic operations.
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‎java/ql/test/query-tests/security/CWE-330/InsecureRandomnessTest.expected

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failures
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testFailures

‎java/ql/test/query-tests/security/CWE-330/InsecureRandomnessTest.ql

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import java
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import semmle.code.java.dataflow.DataFlow
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import semmle.code.java.security.InsecureRandomnessQuery
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import TestUtilities.InlineExpectationsTest
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module WeakRandomTest implements TestSig {
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string getARelevantTag() { result = "hasWeakRandomFlow" }
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predicate hasActualResult(Location location, string element, string tag, string value) {
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tag = "hasWeakRandomFlow" and
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exists(DataFlow::Node sink | InsecureRandomnessFlow::flowTo(sink) |
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sink.getLocation() = location and
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element = sink.toString() and
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value = ""
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)
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}
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}
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import MakeTest<WeakRandomTest>

‎java/ql/test/query-tests/security/CWE-330/WeakRandomCookies.java

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import java.io.IOException;
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import java.util.Random;
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import java.util.concurrent.ThreadLocalRandom;
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import java.security.SecureRandom;
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import javax.servlet.ServletException;
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import javax.servlet.http.HttpServlet;
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import javax.servlet.http.HttpServletRequest;
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import javax.servlet.http.HttpServletResponse;
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import javax.servlet.http.Cookie;
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import org.apache.commons.lang3.RandomStringUtils;
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import org.owasp.esapi.Encoder;
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public class WeakRandomCookies extends HttpServlet {
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HttpServletResponse response;
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public void doGet() {
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Random r = new Random();
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int c = r.nextInt();
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// BAD: The cookie value may be predictable.
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Cookie cookie = new Cookie("name", Integer.toString(c)); // $hasWeakRandomFlow
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Encoder enc = null;
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int c2 = r.nextInt();
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String value = enc.encodeForHTML(Integer.toString(c2));
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// BAD: The cookie value may be predictable.
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Cookie cookie2 = new Cookie("name", value); // $hasWeakRandomFlow
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byte[] bytes = new byte[16];
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r.nextBytes(bytes);
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// BAD: The cookie value may be predictable.
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Cookie cookie3 = new Cookie("name", new String(bytes)); // $hasWeakRandomFlow
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SecureRandom sr = new SecureRandom();
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byte[] bytes2 = new byte[16];
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sr.nextBytes(bytes2);
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// GOOD: The cookie value is unpredictable.
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Cookie cookie4 = new Cookie("name", new String(bytes2));
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ThreadLocalRandom tlr = ThreadLocalRandom.current();
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Cookie cookie5 = new Cookie("name", Integer.toString(tlr.nextInt())); // $hasWeakRandomFlow
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Cookie cookie6 = new Cookie("name", RandomStringUtils.random(10)); // $hasWeakRandomFlow
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Cookie cookie7 = new Cookie("name", RandomStringUtils.randomAscii(10)); // $hasWeakRandomFlow
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long c3 = r.nextLong();
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// BAD: The cookie value may be predictable.
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Cookie cookie8 = new Cookie("name", Long.toString(c3 * 5)); // $hasWeakRandomFlow
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double c4 = Math.random();
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// BAD: The cookie value may be predictable.
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Cookie cookie9 = new Cookie("name", Double.toString(c4)); // $hasWeakRandomFlow
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double c5 = Math.random();
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// BAD: The cookie value may be predictable.
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Cookie cookie10 = new Cookie("name", Double.toString(++c5)); // $hasWeakRandomFlow
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}
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}

‎java/ql/test/query-tests/security/CWE-330/options

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//semmle-extractor-options: --javac-args -cp ${testdir}/../../../stubs/servlet-api-2.4:${testdir}/../../../stubs/apache-commons-lang3-3.7:${testdir}/../../../stubs/esapi-2.0.1

‎java/ql/test/stubs/esapi-2.0.1/org/owasp/esapi/Encoder.java

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‎java/ql/test/stubs/esapi-2.0.1/org/owasp/esapi/reference/DefaultEncoder.java

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