Java: QL Query Detector for JHipster Generated CVE-2019-16303

java/ql/src/Security/CWE/CWE-338/JHipsterGeneratedPRNG.qhelp

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+<!DOCTYPE qhelp PUBLIC
+  "-//Semmle//qhelp//EN"
+  "qhelp.dtd">
+<qhelp>
+<overview>
+<p>This query detects instances of <code>RandomUtil.java</code> that were generated by a <a href="https://www.jhipster.tech/">JHipster</a> version that is vulnerable to <a href="https://github.com/jhipster/jhipster-kotlin/security/advisories/GHSA-j3rh-8vwq-wh84">CVE-2019-16303</a>.</p>
+
+<p>If an app uses <code>RandomUtil.java</code> generated by a vulnerable version of JHipster, attackers can request a password reset token and use this to predict the value of future reset tokens generated by this server. 
+Using this information, they can create a reset link that allows them to take over any account.</p>
+
+<p>This vulnerability has a 
+<a href="https://nvd.nist.gov/vuln-metrics/cvss/v3-calculator?name=CVE-2019-16303&amp;vector=AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H&amp;version=3.1&amp;source=NIST">
+  CVSS v3.0 Base Score of 9.8/10
+</a>.</p>
+</overview>
+
+<example>
+
+<p>The example below shows the vulnerable <code>RandomUtil</code> class generated by <a href="https://www.jhipster.tech/2019/09/13/jhipster-release-6.3.0.html">JHipster prior to version 6.3.0</a>.</p>
+<sample src="JHipsterGeneratedPRNGVulnerable.java" />
+
+<p>Below is a fixed version of the <code>RandomUtil</code> class.</p>
+<sample src="JHipsterGeneratedPRNGFixed.java" />
+
+</example>
+
+<recommendation>
+
+<p>You should refactor the <code>RandomUtil</code> class and replace every call to <code>RandomStringUtils.randomAlphaNumeric</code>. You could regenerate the class using the latest version of JHipster, or use an automated refactoring. For example, using the <a href="https://github.com/moderneinc/jhipster-cwe-338">Patching JHipster CWE-338</a> for the <a href="https://github.com/openrewrite/rewrite">Rewrite project</a>.
+</p>
+</recommendation>
+
+<references>
+
+<li>
+  Cloudflare Blog: 
+  <a href="https://blog.cloudflare.com/why-randomness-matters/">
+    Why secure systems require random numbers
+  </a>
+</li>
+<li>
+  Hacker News: 
+  <a href="https://news.ycombinator.com/item?id=639976">
+    How I Hacked Hacker News (with arc security advisory)
+  </a>
+</li>
+<li>
+  Posts by Pucara Information Security Team:
+  <a href="https://blog.pucarasec.com/2020/05/09/the-java-soothsayer-a-practical-application-for-insecure-randomness-includes-free-0day/">
+    The Java Soothsayer: A practical application for insecure randomness. (Includes free 0day)
+  </a>
+</li>
+
+<!--  LocalWords: CWE random RNG PRNG CSPRNG SecureRandom JHipster -->
+
+</references>
+
+</qhelp>

java/ql/src/Security/CWE/CWE-338/JHipsterGeneratedPRNG.ql

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+/**
+ * @name Detect JHipster Generator Vulnerability CVE-2019-16303
+ * @description Using a vulnerable version of JHipster to generate random numbers makes it easier for attackers to take over accounts.
+ * @kind problem
+ * @problem.severity error
+ * @precision very-high
+ * @id java/jhipster-prng
+ * @tags security
+ *       external/cwe/cwe-338
+ */
+
+import java
+import semmle.code.java.frameworks.apache.Lang
+
+private class PredictableApacheRandomStringUtilsMethod extends Method {
+  PredictableApacheRandomStringUtilsMethod() {
+    this.getDeclaringType() instanceof TypeApacheRandomStringUtils and
+    // The one valid use of this type that uses SecureRandom as a source of data.
+    not this.getName() = "random"
+  }
+}
+
+private class PredictableApacheRandomStringUtilsMethodAccess extends MethodAccess {
+  PredictableApacheRandomStringUtilsMethodAccess() {
+    this.getMethod() instanceof PredictableApacheRandomStringUtilsMethod
+  }
+}
+
+private class VulnerableJHipsterRandomUtilClass extends Class {
+  VulnerableJHipsterRandomUtilClass() {
+    // The package name that JHipster generated the 'RandomUtil' class in was dynamic. Thus 'hasQualifiedName' can not be used here.
+    getName() = "RandomUtil"
+  }
+}
+
+private class VulnerableJHipsterRandomUtilMethod extends Method {
+  VulnerableJHipsterRandomUtilMethod() {
+    this.getDeclaringType() instanceof VulnerableJHipsterRandomUtilClass and
+    this.getName().matches("generate%") and
+    this.getReturnType() instanceof TypeString and
+    exists(ReturnStmt s |
+      s = this.getBody().(SingletonBlock).getStmt() and
+      s.getResult() instanceof PredictableApacheRandomStringUtilsMethodAccess
+    )
+  }
+}
+
+from VulnerableJHipsterRandomUtilMethod method
+select method,
+  "Weak random number generator used in security sensitive method (JHipster CVE-2019-16303)."

java/ql/src/Security/CWE/CWE-338/JHipsterGeneratedPRNGFixed.java

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+import org.apache.commons.lang3.RandomStringUtils;
+
+import java.security.SecureRandom;
+
+/**
+ * Utility class for generating random Strings.
+ */
+public final class RandomUtil {
+    private static final SecureRandom SECURE_RANDOM = new SecureRandom(); // GOOD: Using SecureRandom
+
+    private static final int DEF_COUNT = 20;
+
+    static {
+        SECURE_RANDOM.nextBytes(new byte[64]);
+    }
+
+    private RandomUtil() {
+    }
+
+    private static String generateRandomAlphanumericString() {
+        // GOOD: Passing Secure Random to RandomStringUtils::random
+        return RandomStringUtils.random(DEF_COUNT, 0, 0, true, true, null, SECURE_RANDOM);
+    }
+
+    /**
+     * Generate a password.
+     *
+     * @return the generated password.
+     */
+    public static String generatePassword() {
+        return generateRandomAlphanumericString();
+    }
+
+    /**
+     * Generate an activation key.
+     *
+     * @return the generated activation key.
+     */
+    public static String generateActivationKey() {
+        return generateRandomAlphanumericString();
+    }
+
+    /**
+     * Generate a reset key.
+     *
+     * @return the generated reset key.
+     */
+    public static String generateResetKey() {
+        return generateRandomAlphanumericString();
+    }
+
+    /**
+     * Generate a unique series to validate a persistent token, used in the
+     * authentication remember-me mechanism.
+     *
+     * @return the generated series data.
+     */
+    public static String generateSeriesData() {
+        return generateRandomAlphanumericString();
+    }
+
+    /**
+     * Generate a persistent token, used in the authentication remember-me mechanism.
+     *
+     * @return the generated token data.
+     */
+    public static String generateTokenData() {
+        return generateRandomAlphanumericString();
+    }
+}

java/ql/src/Security/CWE/CWE-338/JHipsterGeneratedPRNGVulnerable.java

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+import org.apache.commons.lang3.RandomStringUtils;
+
+/**
+ * Utility class for generating random Strings.
+ */
+public final class RandomUtil {
+
+    private static final int DEF_COUNT = 20;
+
+    private RandomUtil() {
+    }
+
+    /**
+     * Generate a password.
+     *
+     * @return the generated password.
+     */
+    public static String generatePassword() {
+        return RandomStringUtils.randomAlphanumeric(DEF_COUNT); // BAD: RandomStringUtils does not use SecureRandom
+    }
+
+    /**
+     * Generate an activation key.
+     *
+     * @return the generated activation key.
+     */
+    public static String generateActivationKey() {
+        return RandomStringUtils.randomNumeric(DEF_COUNT); // BAD: RandomStringUtils does not use SecureRandom
+    }
+
+    /**
+     * Generate a reset key.
+     *
+     * @return the generated reset key.
+     */
+    public static String generateResetKey() {
+        return RandomStringUtils.randomNumeric(DEF_COUNT); // BAD: RandomStringUtils does not use SecureRandom
+    }
+
+    /**
+     * Generate a unique series to validate a persistent token, used in the
+     * authentication remember-me mechanism.
+     *
+     * @return the generated series data.
+     */
+    public static String generateSeriesData() {
+        return RandomStringUtils.randomAlphanumeric(DEF_COUNT); // BAD: RandomStringUtils does not use SecureRandom
+    }
+
+    /**
+     * Generate a persistent token, used in the authentication remember-me mechanism.
+     *
+     * @return the generated token data.
+     */
+    public static String generateTokenData() {
+        return RandomStringUtils.randomAlphanumeric(DEF_COUNT); // BAD: RandomStringUtils does not use SecureRandom
+    }
+}

java/ql/src/semmle/code/java/frameworks/apache/Lang.qll

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+/** Definitions related to the Apache Commons Lang library. */
+
+import java
+
+/*--- Types ---*/
+/** The class `org.apache.commons.lang.RandomStringUtils` or `org.apache.commons.lang3.RandomStringUtils`. */
+class TypeApacheRandomStringUtils extends Class {
+  TypeApacheRandomStringUtils() {
+    hasQualifiedName("org.apache.commons.lang", "RandomStringUtils") or
+    hasQualifiedName("org.apache.commons.lang3", "RandomStringUtils")
+  }
+}

java/ql/test/query-tests/security/CWE-338/semmle/tests/JHipsterGeneratedPRNG.expected

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+| vulnerable/RandomUtil.java:20:26:20:41 | generatePassword | Weak random number generator used in security sensitive method (JHipster CVE-2019-16303). |
+| vulnerable/RandomUtil.java:29:26:29:46 | generateActivationKey | Weak random number generator used in security sensitive method (JHipster CVE-2019-16303). |
+| vulnerable/RandomUtil.java:38:26:38:41 | generateResetKey | Weak random number generator used in security sensitive method (JHipster CVE-2019-16303). |
+| vulnerable/RandomUtil.java:48:26:48:43 | generateSeriesData | Weak random number generator used in security sensitive method (JHipster CVE-2019-16303). |
+| vulnerable/RandomUtil.java:57:26:57:42 | generateTokenData | Weak random number generator used in security sensitive method (JHipster CVE-2019-16303). |

java/ql/test/query-tests/security/CWE-338/semmle/tests/JHipsterGeneratedPRNG.qlref

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+Security/CWE/CWE-338/JHipsterGeneratedPRNG.ql

java/ql/test/query-tests/security/CWE-338/semmle/tests/fixed/RandomUtil.java

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+package test.cwe338.cwe.examples.fixed;
+
+import org.apache.commons.lang3.RandomStringUtils;
+
+import java.security.SecureRandom;
+
+/**
+ * Utility class for generating random Strings.
+ */
+public final class RandomUtil {
+    private static final SecureRandom SECURE_RANDOM = new SecureRandom();
+
+    private static final int DEF_COUNT = 20;
+
+    static {
+        SECURE_RANDOM.nextBytes(new byte[64]);
+    }
+
+    private RandomUtil() {
+    }
+
+    private static String generateRandomAlphanumericString() {
+        return RandomStringUtils.random(DEF_COUNT, 0, 0, true, true, null, SECURE_RANDOM);
+    }
+
+    /**
+     * Generate a password.
+     *
+     * @return the generated password.
+     */
+    public static String generatePassword() {
+        return generateRandomAlphanumericString();
+    }
+
+    /**
+     * Generate an activation key.
+     *
+     * @return the generated activation key.
+     */
+    public static String generateActivationKey() {
+        return generateRandomAlphanumericString();
+    }
+
+    /**
+     * Generate a reset key.
+     *
+     * @return the generated reset key.
+     */
+    public static String generateResetKey() {
+        return generateRandomAlphanumericString();
+    }
+
+    /**
+     * Generate a unique series to validate a persistent token, used in the
+     * authentication remember-me mechanism.
+     *
+     * @return the generated series data.
+     */
+    public static String generateSeriesData() {
+        return generateRandomAlphanumericString();
+    }
+
+    /**
+     * Generate a persistent token, used in the authentication remember-me mechanism.
+     *
+     * @return the generated token data.
+     */
+    public static String generateTokenData() {
+        return generateRandomAlphanumericString();
+    }
+}

java/ql/test/query-tests/security/CWE-338/semmle/tests/options

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+//semmle-extractor-options: --javac-args -cp ${testdir}/../../../../../stubs/apache-commons-lang3-3.7

java/ql/test/query-tests/security/CWE-338/semmle/tests/vulnerable/RandomUtil.java

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+package test.cwe338.cwe.examples.vulnerable;
+
+import org.apache.commons.lang3.RandomStringUtils;
+
+/**
+ * Utility class for generating random Strings.
+ */
+public final class RandomUtil {
+
+    private static final int DEF_COUNT = 20;
+
+    private RandomUtil() {
+    }
+
+    /**
+     * Generate a password.
+     *
+     * @return the generated password.
+     */
+    public static String generatePassword() {
+        return RandomStringUtils.randomAlphanumeric(DEF_COUNT);
+    }
+
+    /**
+     * Generate an activation key.
+     *
+     * @return the generated activation key.
+     */
+    public static String generateActivationKey() {
+        return RandomStringUtils.randomNumeric(DEF_COUNT);
+    }
+
+    /**
+     * Generate a reset key.
+     *
+     * @return the generated reset key.
+     */
+    public static String generateResetKey() {
+        return RandomStringUtils.randomNumeric(DEF_COUNT);
+    }
+
+    /**
+     * Generate a unique series to validate a persistent token, used in the
+     * authentication remember-me mechanism.
+     *
+     * @return the generated series data.
+     */
+    public static String generateSeriesData() {
+        return RandomStringUtils.randomAlphanumeric(DEF_COUNT);
+    }
+
+    /**
+     * Generate a persistent token, used in the authentication remember-me mechanism.
+     *
+     * @return the generated token data.
+     */
+    public static String generateTokenData() {
+        return RandomStringUtils.randomAlphanumeric(DEF_COUNT);
+    }
+}