Collect organisation information
Employee information
Organisation’s background
Phone numbers
Locations
Advanced searches
Search engines can be used to gather information about the target organisation. Search results can include , and other information that could be useful.
Search engines crawl the world wide web day and night to index new web pages and files. Sometimes this can lead to indexing confidential information:
Information about employees
Intranet information
Login pages
Documents for internal company use
Confidential spreadsheets with usernames, email addresses, and even passwords
Files containing usernames
Sensitive directories
Service version number (some of which might be vulnerable and unpatched)
Error messages
Google dorking
Google dorking is a technique which involves using a set of search operators and building complex queries. The operators that are used in Google hacking are called dorks.
Email footprinting
Email footprinting involves collecting information from emails by monitoring the email delivery and inspecting the headers:
IP address of the recipient
Geolocation of the recipient
Delivery information
Visited links
Browser and OS information
Reading time
Email headers contain information about the sender, subject, and recipient. All this information is valuable to hackers when planning to attack their target.
Information contained in email headers include:
Sender’s name
IP/Email address of the sender
Mail server
Mail server authentication system
Send and delivery stamp
Unique number of the message
Email tracking tools have the capability of tracking emails and inspecting their headers to extract useful information. The sender is notified of the email being delivered and opened by the recipient.
Assets discovery
Assets discovery involves collecting all the company names owned by a main company and then all the assets of these companies:
Find the acquisitions of the main company, this will give the companies inside the scope.
Find the ASN (if any) of each company, this will give the IP ranges owned by each company.
Use reverse whois lookups to search for other entries (organisation names, domains…) related to the first one (recursively).
Shodan and SSL filters can be used to search for other assets (the SSL trick can be done recursively).
Visit job listing sites
Job advertisements can also tell a lot about an organisation. In addition to revealing names and email addresses, job posts for technical positions could give insight into the target’s systems and infrastructure. The popular job posts might vary from one country to another. Make sure to check job listing sites in the countries where the target would post their ads. And it is always worth checking their website for any job opening and seeing if this can leak any interesting information.