14 KiB
Phising Documents
Microsoft Word performs file data validation prior to opening a file. Data validation is performed in the form of data structure identification, against the OfficeOpenXML standard. If any error occurs during the data structure identification, the file being analysed will not be opened.
Usually Word files containing macros uses the .docm extension. However, it's possible to rename the file changing the file extension and still keep their macro executing capabilities.
For example, an RTF file does not support macros, by design, but a DOCM file renamed to RTF will be handled by Microsoft Word and will be capable of macro execution.
The same internals and mechanisms apply to all software of the Microsoft Office Suite Excel, PowerPoint etc..
You can use the following command to check with extensions are going to be executed by some Office programs:
assoc | findstr /i "word excel powerp"
DOCX files referencing a remote template File –Options –Add-ins –Manage: Templates –Go that includes macros can “execute” macros as well.
Word with external image
Go to: Insert --> Quick Parts --> Field
Categories: Links and References, Filed names: includePicture, and Filename or URL: http://<ip>/whatever
Macros Code
Dim author As String
author = oWB.BuiltinDocumentProperties("Author")
With objWshell1.Exec("powershell.exe -nop -Windowsstyle hidden -Command-")
.StdIn.WriteLine author
.StdIn.WriteBlackLines 1
Autoload functions
The more common they are, the more probable the AV will detect it.
- AutoOpen()
- Document_Open()
Methodology
- Recon the victim
- Select the victim domain.
- Preform some basic web enumeration searching for login portals used by the victim and decide which one you will impersonate.
- Use some OSINT to find emails.
- Prepare the environment
- Buy the domain you are going to use for the phishing assessment
- Configure the email service related records
SPF, DMARC, DKIM, rDNS - Configure the VPS with gophish
- Prepare the templates
- Prepare the email template to redirect to the malicious web page
- Prepare the web page to steal the credentials
- Launch the attack!
Generate similar domain names
Domain Name Variation Techniques
- Keyword: The domain name contains an important keyword of the original domain
e.g., zelster.com-management.com. - hypened subdomain: Change the dot for a hyphen of a subdomain
e.g., www-zelster.com. - New TLD: Same domain using a new TLD
e.g., zelster.org - Homoglyph: It replaces a letter in the domain name with letters that look similar
e.g., zelfser.com. - Transposition: It swaps two letters within the domain name
e.g., zelster.com. - Singularization/Pluralization: Adds or removes “s” at the end of the domain name
e.g., zeltsers.com. - Omission: It removes one of the letters from the domain name
e.g., zelser.com. - Repetition: It repeats one of the letters in the domain name
e.g., zeltsser.com. - Replacement: Like homoglyph but less stealthy. It replaces one of the letters in the domain name, perhaps with a letter in proximity of the original letter on the keyboard
e.g, zektser.com. - Subdomained: Introduce a dot inside the domain name
e.g., ze.lster.com. - Insertion: It inserts a letter into the domain name
e.g., zerltser.com. - Bitsquatting: It anticipates a small portion of systems encountering hardware errors, resulting in the mutation of the resolved domain name by 1 bit.
e.g., xeltser.com. - Missing dot: Append the TLD to the domain name.
e.g., zelstercom.com
Automatic Tools
Websites
- https://dnstwist.it/
- https://dnstwister.report/
- https://www.internetmarketingninjas.com/tools/free-tools/domain-typo-generator/
GoPhish
Installation
You can download it from https://github.com/gophish/gophish/releases/tag/v0.11.0
Download and decompress it inside /opt/gophish and execute /opt/gophish/gophish
You will be given a password for the admin user in port 3333 in the output. Therefore, access that port and use those credentials to change the admin password. You may need to tunnel that port to local:
ssh -L 333:127.0.0.1:3333 <user>@<ip>
Configuration
TLS certificate configuration
Before this step you should have already bought the domain you are going to use and it must be pointing to the IP of the VPS where you are configuring gophish.
DOMAIN="<domain>"
wget https://dl.eff.org/certbot-auto
chmod +x certbot-auto
sudo apt install snapd
sudo snap install core
sudo snap refresh core
sudo apt-get remove certbot
sudo snap install --classic certbot
sudo ln -s /snap/bin/certbot /usr/bin/certbot
certbot certonly --standalone -d "$DOMAIN"
mkdir /opt/gophish/ssl_keys
cp "/etc/letsencrypt/live/$DOMAIN/privkey.pem" /opt/gophish/ssl_keys/key.pem
cp "/etc/letsencrypt/live/$DOMAIN/fullchain.pem" /opt/gophish/ssl_keys/key.crt
Mail configuration
Start installing: apt-get install postfix
Then add the domain to the following files:
- /etc/postfix/virtual_domains
- /etc/postfix/transport
- /etc/postfix/virtual_regexp
Change also the values of the following variables inside /etc/postfix/main.cf
myhostname = <domain> mydestination = $myhostname, <domain>, localhost.com, localhost
Finally modify the files /etc/hostname and /etc/mailname to your domain name and restart your VPS.
Now, create a DNS A record of mail.<domain> pointing to the ip address of the VPS and a DNS MX record pointing to mail.<domain>
Now lets test to send an email:
apt install mailutils
echo "This is the body of the email" | mail -s "This is the subject line" test@email.com
Gophish configuration
Stop the execution of gophish and lets configure it.
Modify /opt/gophish/config.json to the following note the use of https:
{
"admin_server": {
"listen_url": "127.0.0.1:3333",
"use_tls": true,
"cert_path": "gophish_admin.crt",
"key_path": "gophish_admin.key"
},
"phish_server": {
"listen_url": "0.0.0.0:443",
"use_tls": true,
"cert_path": "/opt/gophish/ssl_keys/key.crt",
"key_path": "/opt/gophish/ssl_keys/key.pem"
},
"db_name": "sqlite3",
"db_path": "gophish.db",
"migrations_prefix": "db/db_",
"contact_address": "",
"logging": {
"filename": "",
"level": ""
}
}
Configure gophish service
In order to create the gophish service so it can be started automatically and managed a service you can create the file /etc/init.d/gophish with the following content:
#!/bin/bash
# /etc/init.d/gophish
# initialization file for stop/start of gophish application server
#
# chkconfig: - 64 36
# description: stops/starts gophish application server
# processname:gophish
# config:/opt/gophish/config.json
# From https://github.com/gophish/gophish/issues/586
# define script variables
processName=Gophish
process=gophish
appDirectory=/opt/gophish
logfile=/var/log/gophish/gophish.log
errfile=/var/log/gophish/gophish.error
start() {
echo 'Starting '${processName}'...'
cd ${appDirectory}
nohup ./$process >>$logfile 2>>$errfile &
sleep 1
}
stop() {
echo 'Stopping '${processName}'...'
pid=$(/bin/pidof ${process})
kill ${pid}
sleep 1
}
status() {
pid=$(/bin/pidof ${process})
if [["$pid" != ""| "$pid" != "" ]]; then
echo ${processName}' is running...'
else
echo ${processName}' is not running...'
fi
}
case $1 in
start|stop|status) "$1" ;;
esac
Finish configuring the service and checking it doing:
mkdir /var/log/gophish
chmod +x /etc/init.d/gophish
update-rc.d gophish defaults
#Check the service
service gophish start
service gophish status
ss -l | grep "3333\|443"
service gophish stop
SPAM filters bypass
Wait
The older a domain is the less probable it's going to be caught as spam. Then you should wait as much time as possible at least 1week before the phishing assessment.
Note that even if you have to wait a week you can finish configuring everything now.
Configure Reverse DNS rDNS record
Set a rDNS PTR record that resolves the IP address of the VPS to the domain name.
Sender Policy Framework SPF Record
You must configure a SPF record for the new domain. If you don't know what is a SPF record read the following page:
{% page-ref page="../pentesting/pentesting-smtp/" %}
You can use https://www.spfwizard.net/ to generate your SPF policy use the IP of the VPS machine
This is the content that must be set inside a TXT record inside the domain:
v=spf1 mx a ip4:ip.ip.ip.ip ?all
Domain-based Message Authentication, Reporting & Conformance DMARC Record
You must configure a DMARC record for the new domain. If you don't know what is a DMARC record read the following page:
{% page-ref page="../pentesting/pentesting-smtp/" %}
You have to create a new DNS TXT record pointing the hostname _dmarc.<domain> with the following content:
v=DMARC1; p=none
DomainKeys Identified Mail DKIM
You must configure a DKIM for the new domain. If you don't know what is a DMARC record read the following page:
{% page-ref page="../pentesting/pentesting-smtp/" %}
This tutorial is based on: https://www.digitalocean.com/community/tutorials/how-to-install-and-configure-dkim-with-postfix-on-debian-wheezy
{% hint style="info" %} You need to concatenate both B64 values that the DKIM key generates:
v=DKIM1; h=sha256; k=rsa; p=MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEA0wPibdqPtzYk81njjQCrChIcHzxOp8a1wjbsoNtka2X9QXCZs+iXkvw++QsWDtdYu3q0Ofnr0Yd/TmG/Y2bBGoEgeE+YTUG2aEgw8Xx42NLJq2D1pB2lRQPW4IxefROnXu5HfKSm7dyzML1gZ1U0pR5X4IZCH0wOPhIq326QjxJZm79E1nTh3xj" "Y9N/Dt3+fVnIbMupzXE216TdFuifKM6Tl6O/axNsbswMS1TH812euno8xRpsdXJzFlB9q3VbMkVWig4P538mHolGzudEBg563vv66U8D7uuzGYxYT4WS8NVm3QBMg0QKPWZaKp+bADLkOSB9J2nUpk4Aj9KB5swIDAQAB
{% endhint %}
Test your email configuration score
You can do that using https://www.mail-tester.com/
Just access the page and send an email to the address they give you:
echo "This is the body of the email" | mail -s "This is the subject line" test-iimosa79z@srv1.mail-tester.com
You can also check your email configuration sending an email to check-auth@verifier.port25.com and reading the response for this you will need to **open** port **25** and see the response in the file _/var/mail/root_ if you send the email a as root.
Check that you pass all the tests:
==========================================================
Summary of Results
==========================================================
SPF check: pass
DomainKeys check: neutral
DKIM check: pass
Sender-ID check: pass
SpamAssassin check: ham
Alternatively, you can send a message to a Gmail address that you control, view the received email’s headers in your Gmail inbox, dkim=pass should be present in the Authentication-Results header field.
Authentication-Results: mx.google.com;
spf=pass (google.com: domain of contact@example.com designates --- as permitted sender) smtp.mail=contact@example.com;
dkim=pass header.i=@example.com;
Removing from Spamhouse Blacklist
The page www.mail-tester.com can indicate you if you your domain is being blocked by spamhouse. You can request your domain/IP to be removed at: https://www.spamhaus.org/lookup/
Removing from Microsoft Blacklist
You can request your domain/IP to be removed at https://sender.office.com/.
Detecting the detection
Obviously one of the best ways to know if you have been busted is to search your domain inside blacklists. If it appears listed, somehow your domain was detected as suspicions.
One easy way to check if you domain appears in any blacklist is to use https://malwareworld.com/
However, there are other ways to know if the victim is actively looking for suspicions phishing activity in the wild as explained in:
{% page-ref page="detecting-phising.md" %}
You can buy a domain with a very similar name to the victims domain and/or generate a certificate for a subdomain of a domain controlled by you containing the keyword of the victim's domain. If the victim perform any kind of DNS or HTTP interaction with them, you will now that he is actively looking for suspicious domains and you will need to very very stealth.