PEAS

PEAS is a Python 2 library and command line application for running commands on an ActiveSync server e.g. Microsoft Exchange. It is based on research into Exchange ActiveSync protocol by Adam Rutherford and David Chismon of MWR.

Prerequisites

• python is Python 2, otherwise use python2
• Python Requests library

Significant source files

Path	Functionality
peas/__main__.py	The command line application.
peas/peas.py	The PEAS client class that exclusively defines the interface to PEAS.
peas/py_activesync_helper.py	The helper functions that control the interface to pyActiveSync.
peas/pyActiveSync/client	The pyActiveSync EAS command builders and parsers.

Optional installation

python setup.py install

PEAS application

PEAS can be run without installation from the parent peas directory (containing this readme). PEAS can also be run with the command peas after installation.

Running PEAS

python -m peas [options] <server>

Example usage

Check server

python -m peas 10.207.7.100

Check credentials

python -m peas --check -u luke2 -p ChangeMe123 10.207.7.100

Get emails

python -m peas --emails -u luke2 -p ChangeMe123 10.207.7.100

Save emails to directory

python -m peas --emails -O emails -u luke2 -p ChangeMe123 10.207.7.100

List file shares

python -m peas --list-unc='\\fictitious-dc' -u luke2 -p ChangeMe123 10.207.7.100

python -m peas --list-unc='\\fictitious-dc\guestshare' -u luke2 -p ChangeMe123 10.207.7.100

Note: Using an IP address or FQDN instead of a hostname in the UNC path may fail.

View file on file share

python -m peas --dl-unc='\\fictitious-dc\guestshare\fileonguestshare.txt' -u luke2 -p ChangeMe123 10.207.7.100

Save file from file share

python -m peas --dl-unc='\\fictitious-dc\guestshare\fileonguestshare.txt' -o file.txt -u luke2 -p ChangeMe123 10.207.7.100

Command line arguments

Run python -m peas --help for the latest options.

Options:
  -h, --help            show this help message and exit
  -u USER               username
  -p PASSWORD           password
  --smb-user=USER       username to use for SMB operations
  --smb-pass=PASSWORD   password to use for SMB operations
  --verify-ssl          verify SSL certificates (important)
  -o FILENAME           output to file
  -O PATH               output directory (for specific commands only, not
                        combined with -o)
  -F repr,hex,b64,stdout,stderr,file
                        output formatting and encoding options
  --check               check if account can be accessed with given password
  --emails              retrieve emails
  --list-unc=UNC_PATH   list the files at a given UNC path
  --dl-unc=UNC_PATH     download the file at a given UNC path

PEAS library

PEAS can be imported as a library.

Example code

import peas

# Create an instance of the PEAS client.
client = peas.Peas()

# Display the documentation for the PEAS client.
help(client)

# Disable certificate verification so self-signed certificates don't cause errors.
client.disable_certificate_verification()

# Set the credentials and server to connect to.
client.set_creds({
    'server': '10.207.7.100',
    'user': 'luke2',
    'password': 'ChangeMe123',
})

# Check the credentials are accepted.
print("Auth result:", client.check_auth())

# Retrieve a file share directory listing.
listing = client.get_unc_listing(r'\\fictitious-dc\guestshare')
print(listing)

# Retrieve emails.
emails = client.extract_emails()
print(emails)

Extending

To extend the functionality of PEAS, there is a four step process:

1. Create a builder and parser for the EAS command if it has not been implemented in pyActiveSync/client. Copying an existing source file for another command and then editing it has proved effective. The Microsoft EAS documentation describes the structure of the XML that must be created and parsed from the response.

2. Create a helper function in py_activesync_helper.py that connects to the EAS server over HTTPS, builds and runs the command to achieve the desired functionality. Again, copying an existing function such as get_unc_listing can be effective.

3. Create a method in the Peas class that calls the helper function to achieve the desired functionality. This is where PEAS would decide which backend helper function to call if py-eas-client was also an option.

4. Add command line support for the feature to the PEAS application by editing peas/__main__.py. A new option should be added that when set, calls the method created in the previous step.

Limitations

PEAS has been tested on Kali 2.0 against Microsoft Exchange Server 2013 and 2016. The domain controller was Windows 2012 and the Exchange server was running on the same machine. Results with other configurations may vary.

py-eas-client support is limited to retrieving emails and causes a dependency on Twisted. It was included when the library was being evaluated but it makes sense to remove it from PEAS now, as all functionality can be provided by pyActiveSync.

The licence may be restrictive due to the inclusion of pyActiveSync, which uses the GPLv2.

The requirement to know the hostname of the target machine for file share access may impede enumeration.