SANS ISC: Sysmon and Alternate Data Streams

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SANS ISC InfoSec Forums

Sysmon version 11.10, released a couple of days ago, adds support for capturing content of Alternate Data Streams.

When the content of an ADS is text and less than 1 Kb, the content will be logged in the event log.

Here is an example with a download of a file using Microsoft Edge: an ADS named Zone.Identifier will be created for the downloaded file.

With modern browsers, the Zone.Identifier ADS also contains the referrer (ReferrerUrl) and URL for the download (HostUrl), which can be useful for forensics.

I used the following config file for my tests:

<Sysmon schemaversion="4.32">
  <HashAlgorithms>md5,sha256</HashAlgorithms>
  <DnsLookup>False</DnsLookup>
  <ArchiveDirectory>sysmonarchive</ArchiveDirectory>

  <EventFiltering>
    <FileCreateStreamHash onmatch="exclude"/>

    <CreateRemoteThread onmatch="include"/>
    <DnsQuery onmatch="include"/>
    <DriverLoad onmatch="include"/>
    <FileCreate onmatch="include"/>
    <FileCreateTime onmatch="include"/>
    <FileDelete onmatch="include"/>
    <ImageLoad onmatch="include"/>
    <NetworkConnect onmatch="include"/>
    <PipeEvent onmatch="include"/>
    <ProcessAccess onmatch="include"/>
    <ProcessCreate onmatch="include"/>
    <ProcessTerminate onmatch="include"/>
    <RawAccessRead onmatch="include"/>
    <RegistryEvent onmatch="include"/>
    <WmiEvent onmatch="include"/>
  </EventFiltering>
</Sysmon>

 

Didier Stevens
Senior handler
Microsoft MVP
blog.DidierStevens.com DidierStevensLabs.com