def test_msgconvert(self):
"""
Tested mail from VirusTotal: md5 b89bf096c9e3717f2d218b3307c69bd0
The email used for unittest were found randomly on VirusTotal and
then already publicly available so can not be considered
as privacy violation
"""
f, _ = msgconvert(mail_outlook_1)
self.assertTrue(os.path.exists(f))
m = mailparser.parse_from_file(f)
self.assertEqual(m.from_[0][1], "*****@*****.**")
def __convert_outlook_msg_format(filepath: str) -> BytesIO:
try:
converted_file, stdout = msgconvert(filepath)
except mailparser.exceptions.MailParserOSError as e:
logger.critical(e)
raise MISPMailObjectOutlookException('In order to process parse emails in Outlook format (.msg) you need the package "libemail-outlook-message-perl" and "libemail-address-perl" (on a debian system)')
with open(converted_file, "rb") as f:
pseudofile = BytesIO(f.read())
os.remove(converted_file) # delete temporary file
if pseudofile.getbuffer().nbytes == 0:
logger.critical('msgconvert created an empty file.')
if stdout:
# Probably empty, but in case it's not, let's show it
logger.critical(stdout)
raise MISPMailObjectOutlookException('You probably miss the package libemail-address-perl (on a debian system)')
return pseudofile
def execute(self, request):
parser = eml_parser.eml_parser.EmlParser(include_raw_body=True,
include_attachment_data=True)
content_str = request.file_contents
# Attempt conversion of potential Outlook file -> eml
if request.file_type == "document/office/email":
try:
content_str = msg2eml(request.file_path).as_bytes()
except Exception:
# Try using mailparser to convert
converted_path, _ = msgconvert(request.file_path)
content_str = open(converted_path, "rb").read()
header_agg = {
"From": set(),
"To": set(),
"Cc": set(),
"Sent": set(),
"Reply-To": set(),
"Date": set()
}
# Assume this is an email saved in HTML format
if request.file_type == "code/html":
parsed_html = BeautifulSoup(content_str, "lxml")
valid_headers = [
"To:", "Cc:", "Sent:", "From:", "Subject:", "Reply-To:"
]
if not parsed_html.body or not any(header in parsed_html.body.text
for header in valid_headers):
# We can assume this is just an HTML doc (or lacking body), one of which we can't process
request.result = Result()
return
# Can't trust 'Date' to determine the difference between HTML docs vs HTML emails
valid_headers.append("Date:")
html_email = email.message_from_bytes(content_str)
generator_metadata_content = ""
for meta in parsed_html.find_all("meta"):
if meta.attrs.get("name", None) == "Generator":
generator_metadata_content = meta.attrs.get("content", "")
break
# Process HTML emails generated from Outlook
if generator_metadata_content == "Microsoft Word 15":
paragraphs = parsed_html.body.find_all("p")
# Likely an email that was exported with original email headers
if any(header in paragraphs[0] for header in valid_headers):
for p in paragraphs:
if any(valid_header in p.text
for valid_header in valid_headers):
h_key, h_value = p.text.replace(
"\xa0", "").replace("\r\n", " ").split(":", 1)
html_email[h_key] = h_value
# Subject line indicates the end of the email header, beginning of body
if "Subject" in p.text:
break
# Process HTML emails from MS Exchange Server or missing top-level headers (aggregate headers)
elif (generator_metadata_content
== "Microsoft Word 15 (filtered medium)"
or generator_metadata_content == "Microsoft Exchange Server"
or generator_metadata_content == ""):
subject = None
for div in parsed_html.find_all("div"):
# Header information within divs
if any(header in div.text for header in valid_headers
) and "WordSection1" not in div.attrs.get(
"class", []):
# Usually expect headers to be \n separated in text output but check first
if "\n" in div.text:
for h in div.text.split("\n"):
if any(header in h
for header in valid_headers):
h_key, h_value = h.split(":", 1)
# Implying some malformed message got mixed with the headers of another message
if h_key not in valid_headers:
for header in valid_headers:
if header in h:
h_key = header[:-1]
# Use the latest message's subject (this maintains FW, RE, etc.)
if h_key == "Subject" and not subject:
subject = h_value
elif h_key != "Subject":
header_agg[h_key].add(h_value)
# Document was probably not well formatted, so we'll use the headers as delimiters
else:
header_offset_map = {}
# Determine the position of each header
for header in list(
header_agg.keys()) + ["Subject"]:
if header in div.text:
header_offset_map[div.text.index(
header)] = header
# Use the positions and length of header name to determine an offset
for i in range(len(header_offset_map)):
sorted_keys = sorted(header_offset_map.keys())
header_name = header_offset_map[sorted_keys[i]]
offset = len(
f"{header_name}: ") + sorted_keys[i]
value = (div.text[offset:sorted_keys[i + 1]]
if i < len(header_offset_map) - 1 else
div.text[offset:])
if header_name == "Subject":
subject = value
else:
header_agg[header_name].add(value)
# Assign aggregated info to email object
html_email["Subject"] = subject
for key, value in header_agg.items():
html_email[key] = "; ".join(value)
content_str = html_email.as_bytes()
parsed_eml = parser.decode_email_bytes(content_str)
result = Result()
header = parsed_eml["header"]
if "from" in header or "to" in header:
all_uri = set()
body_words = set(extract_passwords(header["subject"]))
for body_counter, body in enumerate(parsed_eml["body"]):
body_text = BeautifulSoup(body["content"]).text
body_words.update(extract_passwords(body_text))
if request.get_param("extract_body_text"):
fd, path = mkstemp()
with open(path, "w") as f:
f.write(body["content"])
os.close(fd)
request.add_extracted(path, "body_" + str(body_counter),
"Body text")
if "uri" in body:
for uri in body["uri"]:
all_uri.add(uri)
# Words in the email body, used by extract to guess passwords
request.temp_submission_data["email_body"] = list(body_words)
kv_section = ResultSection("Email Headers",
body_format=BODY_FORMAT.KEY_VALUE,
parent=result)
# Basic tags
from_addr = header["from"].strip() if header.get("from",
None) else None
if from_addr and re.match(EMAIL_REGEX, from_addr):
kv_section.add_tag("network.email.address", from_addr)
[
kv_section.add_tag("network.email.address", to.strip())
for to in header["to"] if re.match(EMAIL_REGEX, to.strip())
]
kv_section.add_tag("network.email.date",
str(header["date"]).strip())
subject = header["subject"].strip() if header.get("subject",
None) else None
if subject:
kv_section.add_tag("network.email.subject", subject)
# Add CCs to body and tags
if "cc" in header:
[
kv_section.add_tag("network.email.address", cc.strip())
for cc in header["cc"] if re.match(EMAIL_REGEX, cc.strip())
]
# Add Message ID to body and tags
if "message-id" in header["header"]:
kv_section.add_tag("network.email.msg_id",
header["header"]["message-id"][0].strip())
# Add Tags for received IPs
if "received_ip" in header:
for ip in header["received_ip"]:
ip = ip.strip()
try:
if isinstance(ip_address(ip), IPv4Address):
kv_section.add_tag("network.static.ip", ip)
except ValueError:
pass
# Add Tags for received Domains
if "received_domain" in header:
for dom in header["received_domain"]:
kv_section.add_tag("network.static.domain", dom.strip())
# If we've found URIs, add them to a section
if len(all_uri) > 0:
uri_section = ResultSection("URIs Found:", parent=result)
for uri in all_uri:
uri_section.add_line(uri)
uri_section.add_tag("network.static.uri", uri.strip())
parsed_url = urlparse(uri)
if parsed_url.hostname and re.match(
IP_ONLY_REGEX, parsed_url.hostname):
uri_section.add_tag("network.static.ip",
parsed_url.hostname)
else:
uri_section.add_tag("network.static.domain",
parsed_url.hostname)
# Bring all headers together...
extra_header = header.pop("header", {})
header.pop("received", None)
header.update(extra_header)
# Convert to common format
header["date"] = [self.json_serial(header["date"])]
# Replace with aggregated date(s) if any available
if header_agg["Date"]:
# Replace
if any(
default_date in header["date"] for default_date in
["1970-01-01T00:00:00", "Thu, 01 Jan 1970 00:00:00 +0000"
]):
header["date"] = list(header_agg["Date"])
# Append
else:
header["date"] += list(header_agg["Date"])
(kv_section.add_tag("network.email.date",
str(date).strip())
for date in header_agg["Date"])
# Filter out useless headers from results
self.log.debug(header.keys())
[header.pop(h) for h in self.header_filter if h in header.keys()]
kv_section.set_body(json.dumps(header, default=self.json_serial))
attachments_added = []
if "attachment" in parsed_eml:
attachments = parsed_eml["attachment"]
for attachment in attachments:
fd, path = mkstemp()
with open(path, "wb") as f:
f.write(base64.b64decode(attachment["raw"]))
os.close(fd)
try:
if request.add_extracted(
path,
attachment["filename"],
"Attachment ",
safelist_interface=self.api_interface):
attachments_added.append(attachment["filename"])
except MaxExtractedExceeded:
self.log.warning(
f"Extract limit reached on attachments: "
f"{len(attachment) - len(attachments_added)} not added"
)
break
ResultSection("Extracted Attachments:",
body="\n".join([x for x in attachments_added]),
parent=result)
if request.get_param("save_emlparser_output"):
fd, temp_path = tempfile.mkstemp(dir=self.working_directory)
attachments = parsed_eml.get("attachment", [])
# Remove raw attachments, all attachments up to MaxExtractedExceeded already extracted
for attachment in attachments:
_ = attachment.pop("raw", None)
with os.fdopen(fd, "w") as myfile:
myfile.write(
json.dumps(parsed_eml, default=self.json_serial))
request.add_supplementary(
temp_path, "parsing.json",
"These are the raw results of running GOVCERT-LU's eml_parser"
)
else:
self.log.warning(
"emlParser could not parse EML; no useful information in result's headers"
)
request.result = result
