Monitor calls to the ZwSetEaFile and ZwQueryEaFile Windows API functions as well as binaries used to interact with EA, and consider regularly scanning for the presence of modified information. This may be done to evade some defenses, such as static indicator scanning tools and anti-virus. For a more exhaustive list of utilities that can be used to execute and create ADSs, see. Adversaries may store malicious data or binaries in file attribute metadata instead of directly in files. This syntax (ex: file.ext:ads) is commonly associated with ADSs. Monitor for operations (execution, copies, etc.) with file names that contain colons. There are many ways to create and interact with ADSs using Windows utilities. Forensic techniques exist to identify information stored in NTFS EA. Monitor for contextual data about a file, which may include information such as name, the content (ex: signature, headers, or data/media), user/ower, permissions, may use NTFS file attributes to hide their malicious data in order to evade detection. Many PowerShell commands (such as Get-Item, Set-Item, Remove-Item, and Get-ChildItem) can also accept a -stream parameter to interact with ADSs. The dir /r command can also be used to display ADSs. The Streams tool of Sysinternals can be used to uncover files with ADSs. Ĭonsider adjusting read and write permissions for NTFS EA, though this should be tested to ensure routine OS operations are not impeded. Some variants of the Zeroaccess Trojan have been known to store data in Extended Attributes. WastedLocker has the ability to save and execute files as an alternate data stream (ADS). Valak has the ability save and execute files as alternate data streams (ADS). The Regin malware platform uses Extended Attributes to store encrypted executables. If the victim is using PowerShell 3.0 or later, POWERSOURCE writes its decoded payload to an alternate data stream (ADS) named kernel32.dll that is saved in %PROGRAMDATA%\Windows\. PowerDuke hides many of its backdoor payloads in an alternate data stream (ADS). LoJax has loaded an embedded NTFS DXE driver to be able to access and write to NTFS partitions. Gazer stores configuration items in alternate data streams (ADSs) if the Registry is not accessible. Įxpand can be used to download or copy a file into an alternate data stream. Įsentutl can be used to read and write alternate data streams. The DEADEYE.EMBED variant of DEADEYE can embed its payload in an alternate data stream of a local file. īitPaymer has copied itself to the :bin alternate data stream of a newly created file. Īstaroth can abuse alternate data streams (ADS) to store content for malicious payloads. APT32 used NTFS alternate data streams to hide their payloads.
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