1. Computer Forensics Principles and Practices by Volonino, Anzaldua, and Godwin Chapter 8: E-Mail and Webmail Forensics

2. © Pearson Education Computer Forensics: Principles and Practices 2 In Practice: E-Mail in Senate Investigations of Finance Companies Financial institutions helped Enron manipulate its numbers and mislead investors E-mail proved that banks such as JPMorgan Chase knew very well how Enron was hiding its debt

3. © Pearson Education Computer Forensics: Principles and Practices 3 Importance of E-Mail as Evidence E-mail can be pivotal evidence in a case Due to its informal nature, it does not always represent corporate policy Many cases provide examples of the use of e-mail as evidence  Knox v. State of Indiana  Harley v. McCoach  Nardinelli et al. v. Chevron  Adelyn Lee v. Oracle Corporation

4. © Pearson Education Computer Forensics: Principles and Practices 4 Working with E-Mail E-mail evidence typically used to corroborate or refute other testimony or evidence Can be used by prosecutors or defense parties Two standard methods to send and receive e-mail:  Client/server applications  Webmail

5. © Pearson Education Computer Forensics: Principles and Practices 5 Working with E-Mail (Cont.) E-mail data flow  User has a client program such as Outlook or Eudora  Client program is configured to work with one or more servers  E-mails sent by client reside on PC  A larger machine runs the server program that communicates with the Internet, where it exchanges data with other e-mail servers

6. © Pearson Education Computer Forensics: Principles and Practices 6 Working with E-Mail (Cont.) Sending E-Mail User creates e-mail on her client User issues send command Client moves e-mail to Outbox Server acknowledges client and authenticates e-mail account Client sends e-mail to the server Server sends e-mail to destination e-mail server If the client cannot connect with the server, it keeps trying

7. © Pearson Education Computer Forensics: Principles and Practices 7 Working with E-Mail (Cont.) Receiving E-Mail User opens client and logs on User issues receive command Client contacts server Server acknowledges, authenticates, and contacts mail box for the account Mail downloaded to local computer Messages placed in Inbox to be read POP deletes messages from server; IMAP retains copy on server

8. © Pearson Education Computer Forensics: Principles and Practices 8 Working with E-Mail (Cont.) Working with resident e-mail files  Users are able to work offline with e-mail  E-mail is stored locally, a great benefit for forensic analysts because the e-mail is readily available when the computer is seized  Begin by identifying e-mail clients on system  You can also search by file extensions of common e-mail clients

9. © Pearson Education Computer Forensics: Principles and Practices 9 Working with E-Mail (Cont.) E-Mail ClientExtensionType of File AOL.abi.aim.arl.bag AOL6 organizer file Instant Message launch Organizer file Instant Messenger file Outlook Express.dbx.dgr.email.eml OE mail database OE fax page OE mail message OE electronic mail Outlook.pab.pst.wab Personal address book Personal folder Windows address book (Continued)

10. © Pearson Education Computer Forensics: Principles and Practices 10 Working with E-Mail (Cont.) E-Mail ClientExtensionType of File Lotus Notes.box.ncf.nsf Notes mailbox Notes internal clipboard Notes database Novell Groupwise.mlmSaved e-mail (using WP5.1 format) Eudora.mbxEudora message base

11. © Pearson Education Computer Forensics: Principles and Practices 11 Working with E-Mail (Cont.) Popular e-mail clients:  America Online (AOL)—users have a month to download or save before AOL deletes messages  Outlook Express—installed by default with Windows  Outlook—bundled with Microsoft Office  Eudora—popular free client  Lotus Notes—integrated client option for Lotus Domino server

12. © Pearson Education Computer Forensics: Principles and Practices 12 Working with Webmail Webmail data flow  User opens a browser, logs in to the webmail interface  Webmail server has already placed mail in Inbox  User uses the compose function followed by the send function to create and send mail  Web client communicates behind the scenes to the webmail server to send the message  No e-mails are stored on the local PC; the webmail provider houses all e-mail

13. © Pearson Education Computer Forensics: Principles and Practices 13 Working with Webmail (Cont.) Working with webmail files  Entails a bit more effort to locate files  Temporary files is a good place to start  Useful keywords for webmail programs include: Yahoo! mail: ShowLetter, ShowFolder Compose, “Yahoo! Mail” Hotmail: HoTMail, hmhome, getmsg, doattach, compose Gmail: mail[#]

14. © Pearson Education Computer Forensics: Principles and Practices 14 Working with Webmail (Cont.) Type of E-Mail ProtocolPOP3IMAPWebmail E-mail accessible from anywhere NoYes Remains stored on server No (unless included in a backup of server) YesYes, unless POP3 was used too Dependence on Internet ModerateVery strongStrong Special software required Yes No

15. © Pearson Education Computer Forensics: Principles and Practices 15 Examining E-Mails for Evidence Understanding e-mail headers  The header records information about the sender, receiver, and servers it passes along the way  Most e-mail clients show the header in a short form that does not reveal IP addresses  Most programs have an option to show a long form that reveals complete details

16. © Pearson Education Computer Forensics: Principles and Practices 16 Examining E-Mails for Evidence (Cont.) Most common parts of the e-mail header are logical addresses of senders and receivers Logical address is composed of two parts  The mailbox, which comes before the @ sign  The domain or hostname that comes after the @ sign The mailbox is generally the userid used to log in to the e-mail server The domain is the Internet location of the server that transmits the e-mail

17. © Pearson Education Computer Forensics: Principles and Practices 17 Examining E-Mails for Evidence (Cont.) Reviewing e-mail headers can offer clues to true origins of the mail and the program used to send it Common e-mail header fields include:  Bcc  Cc  Content-Type  Date  From  Message-ID  Received  Subject  To  X-Priority

18. © Pearson Education Computer Forensics: Principles and Practices 18 Examining E-Mails for Evidence (Cont.) IP address registries:  African Network Information  Asia Pacific Network Information  American Registry for Internet Number  Latin American and Caribbean Internet Addresses Registry  Réseaux IP Européens Network Coordination Centre

19. © Pearson Education Computer Forensics: Principles and Practices 19 Examining E-Mails for Evidence (Cont.) Understanding e-mail attachments  MIME standard allows for HTML and multimedia images in e-mail  Searching for base64 can find attachments in unallocated or slack space Anonymous remailers  Allow users to remove identifying IP data to maintain privacy  Stems from users citing the First Amendment and freedom of speech

20. © Pearson Education Computer Forensics: Principles and Practices 20 In Practice: Attempted Attack by Chinese Hackers In December 2005, e-mails sent to the British embassy represented attempt to take control of embassy computers Filtering software logged addresses and identified origin of e-mails in China A Trojan was hidden in attachments to e-mails

21. © Pearson Education Computer Forensics: Principles and Practices 21 Working with Instant Messaging Most widely used IM applications include:  Windows Messenger  Google Talk  AIM (AOL Instant Messenger)  ICQ (“I Seek You”) Instant Messenger Newer versions of IM clients and servers allow the logging of activity Can be more incriminating than e-mail

22. © Pearson Education Computer Forensics: Principles and Practices 22 FYI: Vermont Supreme Court Affirms Conviction Based on IM Evidence Forensic investigator recovered IM conversations relating to photo shoot Expert noted that because IMs are not usually saved, storing them required a special effort