Description
Adversaries may abuse specific file formats to subvert Mark-of-the-Web (MOTW) controls. In Windows, when files are downloaded from the Internet, they are tagged with a hidden NTFS Alternate Data Stream (ADS) named Zone.Identifier with a specific value known as the MOTW.(Citation: Microsoft Zone.Identifier 2020) Files that are tagged with MOTW are protected and cannot perform certain actions. For example, starting in MS Office 10, if a MS Office file has the MOTW, it will open in Protected View. Executables tagged with the MOTW will be processed by Windows Defender SmartScreen that compares files with an allowlist of well-known executables. If the file is not known/trusted, SmartScreen will prevent the execution and warn the user not to run it.(Citation: Beek Use of VHD Dec 2020)(Citation: Outflank MotW 2020)(Citation: Intezer Russian APT Dec 2020)
Adversaries may abuse container files such as compressed/archive (.arj, .gzip) and/or disk image (.iso, .vhd) file formats to deliver malicious payloads that may not be tagged with MOTW. Container files downloaded from the Internet will be marked with MOTW but the files within may not inherit the MOTW after the container files are extracted and/or mounted. MOTW is a NTFS feature and many container files do not support NTFS alternative data streams. After a container file is extracted and/or mounted, the files contained within them may be treated as local files on disk and run without protections.(Citation: Beek Use of VHD Dec 2020)(Citation: Outflank MotW 2020)
Platforms
Mitigations (2)
Disable or Remove Feature or ProgramM1042
Consider disabling auto-mounting of disk image files (i.e., .iso, .img, .vhd, and .vhdx). This can be achieved by modifying the Registry values related to the Windows Explorer file associations in order to disable the automatic Explorer "Mount and Burn" dialog for these file extensions. Note: this will not deactivate the mount functionality itself.(Citation: GitHub MOTW)
Execution PreventionM1038
Consider blocking container file types at web and/or email gateways. Consider unregistering container file extensions in Windows File Explorer.(Citation: Dormann Dangers of VHD 2019)
Threat Groups (3)
| ID | Group | Context |
|---|---|---|
| G0092 | TA505 | [TA505](https://attack.mitre.org/groups/G0092) has used .iso files to deploy malicious .lnk files.(Citation: TrendMicro TA505 Aug 2019) |
| G0082 | APT38 | [APT38](https://attack.mitre.org/groups/G0082) has used ISO and VHD files to deploy malware and to bypass Mark-of-the-Web (MOTW) security measures.(Ci... |
| G0016 | APT29 | [APT29](https://attack.mitre.org/groups/G0016) has embedded ISO images and VHDX files in HTML to evade Mark-of-the-Web.(Citation: ESET T3 Threat Repor... |
Associated Software (2)
| ID | Name | Type | Context |
|---|---|---|---|
| S1025 | Amadey | Malware | [Amadey](https://attack.mitre.org/software/S1025) has modified the `:Zone.Identifier` in the ADS area to zero.(Citation: Korean FSI TA505 2020) |
| S0650 | QakBot | Malware | [QakBot](https://attack.mitre.org/software/S0650) has been packaged in ISO files in order to bypass Mark of the Web (MOTW) security measures.(Citation... |
References
- Beek, C. (2020, December 3). Investigating the Use of VHD Files By Cybercriminals. Retrieved November 17, 2024.
- Hegt, S. (2020, March 30). Mark-of-the-Web from a red team’s perspective. Retrieved February 22, 2021.
- Kennedy, J. (2020, December 9). A Zebra in Gopher's Clothing: Russian APT Uses COVID-19 Lures to Deliver Zebrocy. Retrieved February 22, 2021.
- Microsoft. (2020, August 31). Zone.Identifier Stream Name. Retrieved February 22, 2021.
Frequently Asked Questions
What is T1553.005 (Mark-of-the-Web Bypass)?
T1553.005 is a MITRE ATT&CK technique named 'Mark-of-the-Web Bypass'. It belongs to the Defense Impairment tactic(s). Adversaries may abuse specific file formats to subvert Mark-of-the-Web (MOTW) controls. In Windows, when files are downloaded from the Internet, they are tagged with a hidden NTFS Alternate Data Strea...
How can T1553.005 be detected?
Detection of T1553.005 (Mark-of-the-Web Bypass) typically involves monitoring system logs, network traffic, and endpoint telemetry. Use SIEM rules, EDR solutions, and behavioral analytics to identify suspicious activity associated with this technique.
What mitigations exist for T1553.005?
There are 2 documented mitigations for T1553.005. Key mitigations include: Disable or Remove Feature or Program, Execution Prevention.
Which threat groups use T1553.005?
Known threat groups using T1553.005 include: TA505, APT38, APT29.