Hide Artifacts: NTFS File Attributes
Other sub-techniques of Hide Artifacts (7)
| ID | Name |
|---|---|
| T1564.001 | Hidden Files and Directories |
| T1564.002 | Hidden Users |
| T1564.003 | Hidden Window |
| T1564.004 | NTFS File Attributes |
| T1564.005 | Hidden File System |
| T1564.006 | Run Virtual Instance |
| T1564.007 | VBA Stomping |
Adversaries may use NTFS file attributes to hide their malicious data in order to evade detection. Every New Technology File System (NTFS) formatted partition contains a Master File Table (MFT) that maintains a record for every file/directory on the partition. [1] Within MFT entries are file attributes, [2] such as Extended Attributes (EA) and Data [known as Alternate Data Streams (ADSs) when more than one Data attribute is present], that can be used to store arbitrary data (and even complete files). [1] [3] [4] [5]
Adversaries may store malicious data or binaries in file attribute metadata instead of directly in files. This may be done to evade some defenses, such as static indicator scanning tools and anti-virus. [6] [4]
Procedure Examples
| Name | Description |
|---|---|
| Anchor | |
| APT32 |
APT32 used NTFS alternate data streams to hide their payloads.[8] |
| esentutl |
esentutl can be used to read and write alternate data streams.[9] |
| Expand |
Expand can be used to download or copy a file into an alternate data stream.[10] |
| Gazer |
Gazer stores configuration items in alternate data streams (ADSs) if the Registry is not accessible.[11] |
| LoJax |
LoJax has loaded an embedded NTFS DXE driver to be able to access and write to NTFS partitions.[12] |
| PowerDuke |
PowerDuke hides many of its backdoor payloads in an alternate data stream (ADS).[13] |
| POWERSOURCE |
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 |
| Regin |
The Regin malware platform uses Extended Attributes to store encrypted executables.[15] |
| Valak |
Valak has the ability save and execute files as alternate data streams (ADS).[16][17][18] |
| Zeroaccess |
Some variants of the Zeroaccess Trojan have been known to store data in Extended Attributes.[19] |
Mitigations
| Mitigation | Description |
|---|---|
| Restrict File and Directory Permissions |
Consider adjusting read and write permissions for NTFS EA, though this should be tested to ensure routine OS operations are not impeded. [20] |
Detection
Forensic techniques exist to identify information stored in NTFS EA. [6] Monitor calls to the ZwSetEaFile and ZwQueryEaFile Windows API functions as well as binaries used to interact with EA, [21] [22] and consider regularly scanning for the presence of modified information. [1]
There are many ways to create and interact with ADSs using Windows utilities. Monitor for operations (execution, copies, etc.) with file names that contain colons. This syntax (ex: file.ext:ads[.ext]) is commonly associated with ADSs. [5] [21] [22] For a more exhaustive list of utilities that can be used to execute and create ADSs, see https://gist.github.com/api0cradle/cdd2d0d0ec9abb686f0e89306e277b8f.
The Streams tool of Sysinternals can be used to uncover files with ADSs. The dir /r command can also be used to display ADSs. [23] Many PowerShell commands (such as Get-Item, Set-Item, Remove-Item, and Get-ChildItem) can also accept a -stream parameter to interact with ADSs. [4] [5]
References
- Atkinson, J. (2017, July 18). Host-based Threat Modeling & Indicator Design. Retrieved March 21, 2018.
- Hughes, J. (2010, August 25). NTFS File Attributes. Retrieved March 21, 2018.
- Microsoft. (n.d.). File Streams. Retrieved December 2, 2014.
- Arntz, P. (2015, July 22). Introduction to Alternate Data Streams. Retrieved March 21, 2018.
- Marlin, J. (2013, March 24). Alternate Data Streams in NTFS. Retrieved March 21, 2018.
- Harrell, C. (2012, December 11). Extracting ZeroAccess from NTFS Extended Attributes. Retrieved June 3, 2016.
- Dahan, A. et al. (2019, December 11). DROPPING ANCHOR: FROM A TRICKBOT INFECTION TO THE DISCOVERY OF THE ANCHOR MALWARE. Retrieved September 10, 2020.
- Dahan, A. (2017). Operation Cobalt Kitty. Retrieved December 27, 2018.
- LOLBAS. (n.d.). Esentutl.exe. Retrieved September 3, 2019.
- LOLBAS. (n.d.). Expand.exe. Retrieved February 19, 2019.
- ESET. (2017, August). Gazing at Gazer: Turla’s new second stage backdoor. Retrieved September 14, 2017.
- ESET. (2018, September). LOJAX First UEFI rootkit found in the wild, courtesy of the Sednit group. Retrieved July 2, 2019.
- Adair, S.. (2016, November 9). PowerDuke: Widespread Post-Election Spear Phishing Campaigns Targeting Think Tanks and NGOs. Retrieved January 11, 2017.
- Brumaghin, E. and Grady, C.. (2017, March 2). Covert Channels and Poor Decisions: The Tale of DNSMessenger. Retrieved March 8, 2017.
- Kaspersky Lab's Global Research and Analysis Team. (2014, November 24). THE REGIN PLATFORM NATION-STATE OWNAGE OF GSM NETWORKS. Retrieved December 1, 2014.
- Salem, E. et al. (2020, May 28). VALAK: MORE THAN MEETS THE EYE . Retrieved June 19, 2020.
- Duncan, B. (2020, July 24). Evolution of Valak, from Its Beginnings to Mass Distribution. Retrieved August 31, 2020.
- Reaves, J. and Platt, J. (2020, June). Valak Malware and the Connection to Gozi Loader ConfCrew. Retrieved August 31, 2020.
- Ciubotariu, M. (2014, January 23). Trojan.Zeroaccess.C Hidden in NTFS EA. Retrieved December 2, 2014.
- Sander, J. (2017, October 12). Attack Step 3: Persistence with NTFS Extended Attributes – File System Attacks. Retrieved March 21, 2018.
- Moe, O. (2018, January 14). Putting Data in Alternate Data Streams and How to Execute It. Retrieved June 30, 2018.
- Moe, O. (2018, April 11). Putting Data in Alternate Data Streams and How to Execute It - Part 2. Retrieved June 30, 2018.
- Pravs. (2009, May 25). What you need to know about alternate data streams in windows? Is your Data secure? Can you restore that?. Retrieved March 21, 2018.