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Detecting Windows BITS abuse

 

Windows Background Intelligent Transfer Service (BITS) is a low-bandwidth, asynchronous file transfer mechanism exposed through Component Object Model (COM). BITS is commonly used by updaters, messengers, and other applications which prefer to operate in the background (using available idle bandwidth) without interrupting other networked applications. File transfer tasks are implemented as BITS jobs, which contain a queue of one or more file operations. The interface to create and manage BITS jobs is accessible through PowerShell and the BITSAdmin tool.

Attackers may abuse BITS to download, execute, and clean up after running malicious code. BITS tasks are self-contained in the BITS job database, without new files or registry modifications, and are often permitted by host firewalls. BITS-enabled execution may also enable persistence by creating long-standing jobs, since the default maximum lifetime is 90 days and extendable, or invoking an arbitrary program when a job completes or errors, including after system reboots.

These searches allow you to detect and investigate unusual activities that might indicate BITS abuse.

​Required data

How to use Splunk software for this use case

To deploy this use case, make sure that you have the Splunk ES Content Updates installed on your Splunk Enterprise Security deployment. This extensive content library empowers you to deploy out-of-the-box security detections and analytic stories to enhance your investigations and improve your security posture. If you do not have Splunk Enterprise Security, these detections will still give you an idea of what you can accomplish with SPL in the Splunk platform or with the free app, Splunk Security Essentials.

Some of the detections that can help you with this use case include:

Next steps

Splunk OnDemand Services: Use these credit-based services for direct access to Splunk technical consultants with a variety of technical services from a pre-defined catalog. Most customers have OnDemand Services per their license support plan. Engage the ODS team at OnDemand-Inquires@splunk.com if you require assistance.

In addition, these Splunk resources might help you understand and implement this use case: