Summary
JHipster Kotlin using insecure source of randomness RandomStringUtils before v1.2.0
JHipster Kotlin is using an insecure source of randomness to generate all of its random values. JHipster Kotlin relies upon apache commons lang3 RandomStringUtils.
From the documentation:
Caveat: Instances of Random, upon which the implementation of this class relies, are not cryptographically secure.
- https://commons.apache.org/proper/commons-lang/javadocs/api-3.9/org/apache/commons/lang3/RandomStringUtils.html
Here are the examples of JHipster Kotlin's use of an insecure PRNG:
Proof Of Concepts Already Exist
There has been a POC of taking one RNG value generated RandomStringUtils and reversing it to generate all of the past/future RNG values public since March 3rd, 2018.
POC Repository: https://github.com/alex91ar/randomstringutils
Potential Impact Technical
All that is required is to get one password reset token from a JHipster Kotlin generated service and using the POC above, you can reverse what all future password reset tokens to be generated by this server. This allows an attacker to pick and choose what account they would like to takeover by sending account password reset requests for targeted accounts.
Potential Impact Scale
Not as large as for the original jhipster project as the kotlin blueprint is not that widely used.
Workarounds
Change the content of RandomUtil.kt like this:
import java.security.SecureRandom
import org.apache.commons.lang3.RandomStringUtils
private const val DEF_COUNT = 20
object RandomUtil {
private val secureRandom: SecureRandom = SecureRandom()
init {
secureRandom.nextBytes(byteArrayOf(64.toByte()))
}
private fun generateRandomAlphanumericString(): String {
return RandomStringUtils.random(DEF_COUNT, 0, 0, true, true, null, secureRandom)
}
/**
* Generate a password.
*
* @return the generated password.
*/
fun generatePassword(): String = generateRandomAlphanumericString()
}
Important is to exchange every call of RandomStringUtils.randomAlphaNumeric.
For more information
If you have any questions or comments about this advisory:
- Open an issue in JHipster Kotlin
Impact
CVE-2019-16303 has a CVSS score of 9.8 (Critical). The vector is network-reachable, no privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (1.2.0); upgrading removes the vulnerable code path.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
Already deployed Kodem?
See it in your environmentNew to Kodem? Get a demo →Remediation advice
Update your generated applications to > 1.2.0
Frequently Asked Questions
- What is CVE-2019-16303? CVE-2019-16303 is a critical-severity security vulnerability in generator-jhipster-kotlin (npm), affecting versions < 1.2.0. It is fixed in 1.2.0.
- How severe is CVE-2019-16303? CVE-2019-16303 has a CVSS score of 9.8 (Critical). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
- Which versions of generator-jhipster-kotlin are affected by CVE-2019-16303? generator-jhipster-kotlin (npm) versions < 1.2.0 is affected.
- Is there a fix for CVE-2019-16303? Yes. CVE-2019-16303 is fixed in 1.2.0. Upgrade to this version or later.
- Is CVE-2019-16303 exploitable, and should I be worried? Whether CVE-2019-16303 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether CVE-2019-16303 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
- How do I fix CVE-2019-16303? Upgrade
generator-jhipster-kotlinto 1.2.0 or later.