refactored to be more reliable (e.g. charset detection)

pull/4/head
Sascha Rommelfangen 2017-05-31 14:52:47 +02:00
parent 9f1b54377e
commit 9a326acde8
2 changed files with 57 additions and 34 deletions

View File

@ -15,10 +15,9 @@ from email.generator import Generator
import tempfile
import socket
import syslog
import ftfy
syslog.openlog(logoption=syslog.LOG_PID, facility=syslog.LOG_USER)
def is_valid_ipv4_address(address):
try:
socket.inet_pton(socket.AF_INET, address)
@ -47,32 +46,47 @@ email_subject = config.email_subject_prefix
try:
if not sys.stdin.isatty():
email_data = b''
mailcontent = "".join(sys.stdin)
mailcontent = sys.stdin.buffer.read().decode("utf-8", "ignore")
syslog.syslog(mailcontent)
msg = email.message_from_string(mailcontent)
mail_subject = msg.get('Subject').encode()
mail_subject = msg.get('Subject').encode("utf-8", "ignore")
for part in msg.walk():
if part.get_content_charset() is None:
# This could probably be detected
charset = 'utf-8'
else:
charset = part.get_content_charset()
if part.get_content_maintype() == 'multipart':
continue
if part.get_content_maintype() == 'text':
part.set_charset(charset)
email_data += part.get_payload(decode=True)
email_subject += mail_subject
stdin_used = True
except Exception as e:
print(e)
syslog.syslog("EXCEPTION")
syslog.syslog(str(e))
pass
try:
if not stdin_used:
email_data = sys.argv[1].encode()
email_subject = sys.argv[2].encode()
email_data = sys.argv[1]
email_subject = sys.argv[2]
except:
if debug:
syslog.syslog("FATAL ERROR: Not all required input received")
sys.exit(1)
if debug:
syslog.syslog("Encoding of subject: {0}".format(ftfy.guess_bytes(email_subject)[1]))
syslog.syslog("Encoding of body: {0}".format(ftfy.guess_bytes(email_data)[1]))
email_data = ftfy.fix_text(email_data.decode("utf-8", "ignore"))
email_subject = ftfy.fix_text(email_subject.decode("utf-8", "ignore"))
if debug:
syslog.syslog(str(email_subject))
syslog.syslog(str(email_data))
syslog.syslog(email_subject)
syslog.syslog(email_data)
misp_url = config.misp_url
misp_key = config.misp_key
@ -94,13 +108,15 @@ stopword = config.stopword
hash_only_tags = config.hash_only_tags
forward_identifiers = config.forward_identifiers
original_email_data = email_data
# Ignore lines in body of message
for ignoreline in ignorelist:
email_data = re.sub(ignoreline, b"", email_data)
email_data = re.sub(ignoreline, "", email_data)
# Remove words from subject
for removeword in removelist:
email_subject = re.sub(removeword, b"", email_subject)
email_subject = re.sub(removeword, "", email_subject)
def init(url, key):
return PyMISP(url, key, misp_verifycert, 'json')
@ -110,14 +126,16 @@ tlp_tag = tlptag_default
tlptags = config.tlptags
for tag in tlptags:
for alternativetag in tlptags[tag]:
if alternativetag.encode() in email_data.lower():
if alternativetag in email_data.lower():
tlp_tag = tag
# Create the MISP event
misp = init(misp_url, misp_key)
new_event = misp.new_event(info=email_subject.decode('utf-8', 'ignore'), distribution=0, threat_level_id=3, analysis=1)
new_event = misp.new_event(info=email_subject, distribution=0, threat_level_id=3, analysis=1)
misp.add_tag(new_event, tlp_tag)
#if original_email_data:
# misp.add_named_attribute(new_event, 'email-body', original_email_data.decode('utf-8', 'ignore'), to_ids=False)
# Add additional tags depending on others
for tag in dependingtags:
if tag in tlp_tag:
@ -142,7 +160,7 @@ for identifier in forward_identifiers:
email_data = t_email_data
# Refang email data
email_data = refang(email_data.decode('utf-8', 'ignore'))
email_data = refang(email_data)
## Extract various IOCs
@ -158,7 +176,7 @@ f = Faup()
# Add tags according to configuration
for malware in malwaretags:
if malware.encode() in email_subject.lower():
if malware in email_subject.lower():
for tag in malwaretags[malware]:
misp.add_tag(new_event, tag)
@ -182,10 +200,10 @@ if (len(hashlist_md5) > 0) or (len(hashlist_sha1) > 0) or (len(hashlist_sha256)
for entry in urllist:
ids_flag = True
f.decode(entry)
domainname = f.get_domain()
hostname = f.get_host()
domainname = f.get_domain().decode('utf-8', 'ignore')
hostname = f.get_host().decode('utf-8', 'ignore')
if debug:
syslog.syslog(domainname.decode("utf-8", "ignore"))
syslog.syslog(domainname)
if domainname not in excludelist:
if domainname in internallist:
misp.add_named_attribute(new_event, 'link', entry, category='Internal reference', to_ids=False, distribution=0)
@ -202,24 +220,23 @@ for entry in urllist:
else:
misp.add_url(new_event, entry, category='Network activity', to_ids=ids_flag)
if debug:
syslog.syslog(hostname.decode("utf-8", "ignore"))
syslog.syslog(hostname)
port = f.get_port()
comment = ""
if port:
comment = "on port: " + str(port)
if is_valid_ipv4_address(hostname.decode('utf-8', 'ignore')):
misp.add_ipdst(new_event, hostname.decode('utf-8', 'ignore'), comment=comment, category='Network activity', to_ids=False)
if is_valid_ipv4_address(hostname):
misp.add_ipdst(new_event, hostname, comment=comment, category='Network activity', to_ids=False)
else:
misp.add_hostname(new_event, hostname.decode('utf-8', 'ignore'), comment=comment, category='Network activity', to_ids=ids_flag)
misp.add_hostname(new_event, hostname, comment=comment, category='Network activity', to_ids=ids_flag)
try:
for rdata in dns.resolver.query(hostname.decode('utf-8', 'ignore'), 'A'):
for rdata in dns.resolver.query(hostname, 'A'):
if debug:
syslog.syslog(str(rdata))
misp.add_ipdst(new_event, rdata.to_text(), category='Network activity', to_ids=False, comment=hostname.decode('utf-8', 'ignore'))
misp.add_ipdst(new_event, rdata.to_text(), category='Network activity', to_ids=False, comment=hostname)
except Exception as e:
print (e)
if debug:
syslog.syslog("DNS unsuccessful")
syslog.syslog("DNS unsuccessful for: {0}".format(str(rdata)))
# Try to add attachments
if stdin_used:
@ -233,3 +250,5 @@ if stdin_used:
output.write(part.get_payload(decode=True))
misp.upload_sample(filename, output_path, new_event, distribution=None, to_ids=True, category=None, comment=None, info='My Info', analysis=None, threat_level_id=None)
output.close()
syslog.syslog("Job finished.")

View File

@ -9,21 +9,25 @@ debug = False
nameservers = ['149.13.33.69']
email_subject_prefix = b'M2M - '
excludelist = (b'google.com', b'microsoft.com')
externallist = (b'virustotal.com', b'malwr.com', b'hybrid-analysis.com', b'emergingthreats.net')
internallist = (b'internal.system.local')
noidsflaglist = (b'myexternalip.com', b'ipinfo.io', b'icanhazip.com', b'wtfismyip.com', b'ipecho.net', b'api.ipify.org', b'checkip.amazonaws.com', b'whatismyipaddress.com', b'google.com', b'dropbox.com')
excludelist = ('google.com', 'microsoft.com')
externallist = ('virustotal.com', 'malwr.com', 'hybrid-analysis.com', 'emergingthreats.net')
internallist = ('internal.system.local')
noidsflaglist = ( 'myexternalip.com', 'ipinfo.io', 'icanhazip.com', 'wtfismyip.com', 'ipecho.net',
'api.ipify.org', 'checkip.amazonaws.com', 'whatismyipaddress.com', 'google.com',
'dropbox.com'
)
# Stop parsing when this term is found
stopword = b'Whois & IP Information'
# Ignore lines in body of message containing:
ignorelist = (b".*From: .*\n?", b".*Sender: .*\n?", b".*Received: .*\n?", b".*Sender IP: .*\n?",
b".*Reply-To: .*\n?", b".*Registrar WHOIS Server: .*\n?", b".*Registrar: .*\n?",
b".*Domain Status: .*\n?", b".*Registrant Email: .*\n?", b".*IP Location: .*\n?")
ignorelist = ( ".*From: .*\n?", ".*Sender: .*\n?", ".*Received: .*\n?", ".*Sender IP: .*\n?",
".*Reply-To: .*\n?", ".*Registrar WHOIS Server: .*\n?", ".*Registrar: .*\n?",
".*Domain Status: .*\n?", ".*Registrant Email: .*\n?", ".*IP Location: .*\n?"
)
# Remove "[tags]", "Re: ", "Fwd: " from subject
removelist = (b"[\(\[].*?[\)\]]", b"Re: ", b"Fwd: ")
removelist = ("[\(\[].*?[\)\]]", "Re: ", "Fwd: ")
# TLP tag setup
# Tuples contain different variations of spelling