Hiding Breadcrumbs – Antiforensics on SAP BusinessObjects

At Troopers 14, JP and I gave a talk called “Anti-Forensics on SAP Systems”. The talk focused on the methods attackers could use to hide their tracks on an SAP system. This blog post highlights one of the attacks we discussed.

SAP BusinessObjects has long supported Auditing and it has been enabled within the product by default for a number of years. By design all Audit events are written to the Auditing Data Store (ADS) on a schedule. However, as BO is designed to be a distributed platform, there is a delay between the moment when an event occurs and the time that event reaches the ADS. As discussed in the Administrator Guide, the steps before an event reaches the ADS are as follows:

  1. After an event occurs (e.g. Logon, Report Generation) the Auditee writes the event to a temporary file.
  2. The Auditor polls all auditees for new events on a set schedule. In BO4, the polling interval is dependent on the utilization of the Auditor. Higher utilization means that the Auditees are polled less often. In one of the lab system’s the delay is typically 3 minutes with 1% utilization.
  3. If an auditee has new events, it takes them from the temporary file and sends them to the auditor in a batch.
  4. The auditee waits to receive confirmation from the auditor that the events have been received.
  5. After confirmation, the auditee deletes the events from the temporary file.

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