Email Storage: Server vs. Workstation

Determining the location of email data—whether on a server or a workstation—is a pivotal first step for forensic investigators.

Email Storage Locations

1. Server-Based Storage:

• Business Environments: In corporate settings, the email server typically hosts the most recent email traffic, while workstations often store older messages or synchronize mailboxes.

• Challenges: Email archives may be found in unexpected locations on workstations due to varying IT policies or system administrator oversights.
  

2. Workstation-Based Storage:

• Local Storage: Workstations often hold offline or archived email data, particularly older messages that are no longer actively synchronized with the server.

• Access: Limited IT controls on workstations can result in email archives being stored outside of intended locations, complicating forensic analysis.

Way for Email Analysis:

• Advanced Indexing & Filtering: Narrow down the scope to relevant messages.

• Threading & Clustering: Facilitates focused investigation.

• Deleted Message Recovery: Retrieve soft-deleted messages within retention periods.

• Multi-Account Access: Access multiple user accounts for comprehensive review.

• Deduplication: Eliminate duplicate messages to streamline review. Recommended Tools:

• Forensic Suites: X-Ways, EnCase, FTK

• Dedicated Email Tools: SysTools Mail Examiner, Aid4Mail, Emailchemy, Logikcull

Example:

Microsoft Exchange:

• Market Leader: Predominantly used in corporate enterprises, often deployed on standalone or virtualized servers.
  

Storage Structure:

• Exchange 2007: Utilizes .EDB database files, often located in C:\Program Files\Microsoft\Exchange Server\Mailbox\First Storage Group\Mailbox Database.edb.

• Prior to Exchange 2007: Comprises .EDB and .STM files, both essential for forensic analysis.

• .log Files: Vital for data recovery, capturing transactions before committing to .EDB.

• eseutil Tool: Enables log replay and data import into .EDB files for recovery and analysis.

• Storage Groups: Newer Exchange databases can be segmented into multiple storage groups, each containing several database files.

Acquisition & Collaboration:

• Server Administrator Collaboration: Essential for comprehensive data acquisition.

• Mailbox Export: Mailboxes can be exported to .PST format as an alternative data source.
  

Conclusion

Understanding email storage nuances—be it server-based or workstation-based—is indispensable for forensic investigators. Collaboration with server administrators and leveraging specialized tools can significantly enhance the efficiency and thoroughness of email forensic investigations.

Akash Patel